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Essay on Obesity
List of essays on obesity, essay on obesity – short essay (essay 1 – 150 words), essay on obesity (essay 2 – 250 words), essay on obesity – written in english (essay 3 – 300 words), essay on obesity – for school students (class 5, 6, 7, 8, 9, 10, 11 and 12 standard) (essay 4 – 400 words), essay on obesity – for college students (essay 5 – 500 words), essay on obesity – with causes and treatment (essay 6 – 600 words), essay on obesity – for science students (essay 7 – 750 words), essay on obesity – long essay for medical students (essay 8 – 1000 words).
Obesity is a chronic health condition in which the body fat reaches abnormal level. Obesity occurs when we consume much more amount of food than our body really needs on a daily basis. In other words, when the intake of calories is greater than the calories we burn out, it gives rise to obesity.
Audience: The below given essays are exclusively written for school students (Class 5, 6, 7, 8, 9, 10, 11 and 12 Standard), college, science and medical students.
Obesity means being excessively fat. A person would be said to be obese if his or her body mass index is beyond 30. Such a person has a body fat rate that is disproportionate to his body mass.
Obesity and the Body Mass Index:
The body mass index is calculated considering the weight and height of a person. Thus, it is a scientific way of determining the appropriate weight of any person. When the body mass index of a person indicates that he or she is obese, it exposes the person to make health risk.
There are two major ways to get the body mass index of a person to a moderate rate. The first is to maintain a strict diet. The second is to engage in regular physical exercise. These two approaches are aimed at reducing the amount of fat in the body.
Obesity can lead to sudden death, heart attack, diabetes and may unwanted illnesses. Stop it by making healthy choices.
Obesity has become a big concern for the youth of today’s generation. Obesity is defined as a medical condition in which an individual gains excessive body fat. When the Body Mass Index (BMI) of a person is over 30, he/ she is termed as obese.
Obesity can be a genetic problem or a disorder that is caused due to unhealthy lifestyle habits of a person. Physical inactivity and the environment in which an individual lives, are also the factors that leads to obesity. It is also seen that when some individuals are in stress or depression, they start cultivating unhealthy eating habits which eventually leads to obesity. Medications like steroids is yet another reason for obesity.
Obesity has several serious health issues associated with it. Some of the impacts of obesity are diabetes, increase of cholesterol level, high blood pressure, etc. Social impacts of obesity includes loss of confidence in an individual, lowering of self-esteem, etc.
The risks of obesity needs to be prevented. This can be done by adopting healthy eating habits, doing some physical exercise regularly, avoiding stress, etc. Individuals should work on weight reduction in order to avoid obesity.
Obesity is indeed a health concern and needs to be prioritized. The management of obesity revolves around healthy eating habits and physical activity. Obesity, if not controlled in its initial stage can cause many severe health issues. So it is wiser to exercise daily and maintain a healthy lifestyle rather than being the victim of obesity.
Obesity can be defined as the clinical condition where accumulation of excessive fat takes place in the adipose tissue leading to worsening of health condition. Usually, the fat is deposited around the trunk and also the waist of the body or even around the periphery.
Obesity is actually a disease that has been spreading far and wide. It is preventable and certain measures are to be taken to curb it to a greater extend. Both in the developing and developed countries, obesity has been growing far and wide affecting the young and the old equally.
The alarming increase in obesity has resulted in stimulated death rate and health issues among the people. There are several methods adopted to lose weight and they include different diet types, physical activity and certain changes in the current lifestyle. Many of the companies are into minting money with the concept of inviting people to fight obesity.
In patients associated with increased risk factor related to obesity, there are certain drug therapies and other procedures adopted to lose weight. There are certain cost effective ways introduced by several companies to enable clinic-based weight loss programs.
Obesity can lead to premature death and even cause Type 2 Diabetes Mellitus. Cardiovascular diseases have also become the part and parcel of obese people. It includes stroke, hypertension, gall bladder disease, coronary heart disease and even cancers like breast cancer, prostate cancer, endometrial cancer and colon cancer. Other less severe arising due to obesity includes osteoarthritis, gastro-esophageal reflux disease and even infertility.
Hence, serious measures are to be taken to fight against this dreadful phenomenon that is spreading its wings far and wide. Giving proper education on benefits of staying fit and mindful eating is as important as curbing this issue. Utmost importance must be given to healthy eating habits right from the small age so that they follow the same until the end of their life.
Obesity is majorly a lifestyle disease attributed to the extra accumulation of fat in the body leading to negative health effects on a person. Ironically, although prevalent at a large scale in many countries, including India, it is one of the most neglect health problems. It is more often ignored even if told by the doctor that the person is obese. Only when people start acquiring other health issues such as heart disease, blood pressure or diabetes, they start taking the problem of obesity seriously.
Obesity Statistics in India:
As per a report, India happens to figure as the third country in the world with the most obese people. This should be a troubling fact for India. However, we are yet to see concrete measures being adopted by the people to remain fit.
Causes of Obesity:
Sedentary lifestyle, alcohol, junk food, medications and some diseases such as hypothyroidism are considered as the factors which lead to obesity. Even children seem to be glued to televisions, laptops and video games which have taken away the urge for physical activities from them. Adding to this, the consumption of junk food has further aggravated the growing problem of obesity in children.
In the case of adults, most of the professions of today make use of computers which again makes people sit for long hours in one place. Also, the hectic lifestyle of today makes it difficult for people to spare time for physical activities and people usually remain stressed most of the times. All this has contributed significantly to the rise of obesity in India.
Obesity and BMI:
Body Mass Index (BMI) is the measure which allows a person to calculate how to fit he or she is. In other words, the BMI tells you if you are obese or not. BMI is calculated by dividing the weight of a person in kg with the square of his / her height in metres. The number thus obtained is called the BMI. A BMI of less than 25 is considered optimal. However, if a person has a BMI over 30 he/she is termed as obese.
What is a matter of concern is that with growing urbanisation there has been a rapid increase of obese people in India? It is of utmost importance to consider this health issue a serious threat to the future of our country as a healthy body is important for a healthy soul. We should all be mindful of what we eat and what effect it has on our body. It is our utmost duty to educate not just ourselves but others as well about this serious health hazard.
Obesity can be defined as a condition (medical) that is the accumulation of body fat to an extent that the excess fat begins to have a lot of negative effects on the health of the individual. Obesity is determined by examining the body mass index (BMI) of the person. The BMI is gotten by dividing the weight of the person in kilogram by the height of the person squared.
When the BMI of a person is more than 30, the person is classified as being obese, when the BMI falls between 25 and 30, the person is said to be overweight. In a few countries in East Asia, lower values for the BMI are used. Obesity has been proven to influence the likelihood and risk of many conditions and disease, most especially diabetes of type 2, cardiovascular diseases, sleeplessness that is obstructive, depression, osteoarthritis and some cancer types.
In most cases, obesity is caused through a combination of genetic susceptibility, a lack of or inadequate physical activity, excessive intake of food. Some cases of obesity are primarily caused by mental disorder, medications, endocrine disorders or genes. There is no medical data to support the fact that people suffering from obesity eat very little but gain a lot of weight because of slower metabolism. It has been discovered that an obese person usually expends much more energy than other people as a result of the required energy that is needed to maintain a body mass that is increased.
It is very possible to prevent obesity with a combination of personal choices and social changes. The major treatments are exercising and a change in diet. We can improve the quality of our diet by reducing our consumption of foods that are energy-dense like those that are high in sugars or fat and by trying to increase our dietary fibre intake.
We can also accompany the appropriate diet with the use of medications to help in reducing appetite and decreasing the absorption of fat. If medication, exercise and diet are not yielding any positive results, surgery or gastric balloon can also be carried out to decrease the volume of the stomach and also reduce the intestines’ length which leads to the feel of the person get full early or a reduction in the ability to get and absorb different nutrients from a food.
Obesity is the leading cause of ill-health and death all over the world that is preventable. The rate of obesity in children and adults has drastically increased. In 2015, a whopping 12 percent of adults which is about 600 million and about 100 million children all around the world were found to be obese.
It has also been discovered that women are more obese than men. A lot of government and private institutions and bodies have stated that obesity is top of the list of the most difficult and serious problems of public health that we have in the world today. In the world we live today, there is a lot of stigmatisation of obese people.
We all know how troubling the problem of obesity truly is. It is mainly a form of a medical condition wherein the body tends to accumulate excessive fat which in turn has negative repercussions on the health of an individual.
Given the current lifestyle and dietary style, it has become more common than ever. More and more people are being diagnosed with obesity. Such is its prevalence that it has been termed as an epidemic in the USA. Those who suffer from obesity are at a much higher risk of diabetes, heart diseases and even cancer.
In order to gain a deeper understanding of obesity, it is important to learn what the key causes of obesity are. In a layman term, if your calorie consumption exceeds what you burn because of daily activities and exercises, it is likely to lead to obesity. It is caused over a prolonged period of time when your calorie intake keeps exceeding the calories burned.
Here are some of the key causes which are known to be the driving factors for obesity.
If your diet tends to be rich in fat and contains massive calorie intake, you are all set to suffer from obesity.
With most people sticking to their desk jobs and living a sedentary lifestyle, the body tends to get obese easily.
Of course, the genetic framework has a lot to do with obesity. If your parents are obese, the chance of you being obese is quite high.
The weight which women gain during their pregnancy can be very hard to shed and this is often one of the top causes of obesity.
If you are not getting an adequate amount of sleep, it can have an impact on the hormones which might trigger hunger signals. Overall, these linked events tend to make you obese.
There are several hormonal changes which are known to be direct causes of obesity. The imbalance of the thyroid stimulating hormone, for instance, is one of the key factors when it comes to obesity.
Now that we know the key causes, let us look at the possible ways by which you can handle it.
Treatment for Obesity:
As strange as it may sound, the treatment for obesity is really simple. All you need to do is follow the right diet and back it with an adequate amount of exercise. If you can succeed in doing so, it will give you the perfect head-start into your journey of getting in shape and bidding goodbye to obesity.
There are a lot of different kinds and styles of diet plans for obesity which are available. You can choose the one which you deem fit. We recommend not opting for crash dieting as it is known to have several repercussions and can make your body terribly weak.
The key here is to stick to a balanced diet which can help you retain the essential nutrients, minerals, and, vitamins and shed the unwanted fat and carbs.
Just like the diet, there are several workout plans for obesity which are available. It is upon you to find out which of the workout plan seems to be apt for you. Choose cardio exercises and dance routines like Zumba to shed the unwanted body weight. Yoga is yet another method to get rid of obesity.
So, follow a blend of these and you will be able to deal with the trouble of obesity in no time. We believe that following these tips will help you get rid of obesity and stay in shape.
Obesity and overweight is a top health concern in the world due to the impact it has on the lives of individuals. Obesity is defined as a condition in which an individual has excessive body fat and is measured using the body mass index (BMI) such that, when an individual’s BMI is above 30, he or she is termed obese. The BMI is calculated using body weight and height and it is different for all individuals.
Obesity has been determined as a risk factor for many diseases. It results from dietary habits, genetics, and lifestyle habits including physical inactivity. Obesity can be prevented so that individuals do not end up having serious complications and health problems. Chronic illnesses like diabetes, heart diseases and relate to obesity in terms of causes and complications.
Factors Influencing Obesity:
Obesity is not only as a result of lifestyle habits as most people put it. There are other important factors that influence obesity. Genetics is one of those factors. A person could be born with genes that predispose them to obesity and they will also have difficulty in losing weight because it is an inborn factor.
The environment also influences obesity because the diet is similar in certain environs. In certain environments, like school, the food available is fast foods and the chances of getting healthy foods is very low, leading to obesity. Also, physical inactivity is an environmental factor for obesity because some places have no fields or tracks where people can jog or maybe the place is very unsafe and people rarely go out to exercise.
Mental health affects the eating habits of individuals. There is a habit of stress eating when a person is depressed and it could result in overweight or obesity if the person remains unhealthy for long period of time.
The overall health of individuals also matter. If a person is unwell and is prescribed with steroids, they may end up being obese. Steroidal medications enable weight gain as a side effect.
Complications of Obesity:
Obesity is a health concern because its complications are severe. Significant social and health problems are experienced by obese people. Socially, they will be bullied and their self-esteem will be low as they will perceive themselves as unworthy.
Chronic illnesses like diabetes results from obesity. Diabetes type 2 has been directly linked to obesity. This condition involves the increased blood sugars in the body and body cells are not responding to insulin as they should. The insulin in the body could also be inadequate due to decreased production. High blood sugar concentrations result in symptoms like frequent hunger, thirst and urination. The symptoms of complicated stages of diabetes type 2 include loss of vision, renal failure and heart failure and eventually death. The importance of having a normal BMI is the ability of the body to control blood sugars.
Another complication is the heightened blood pressures. Obesity has been defined as excessive body fat. The body fat accumulates in blood vessels making them narrow. Narrow blood vessels cause the blood pressures to rise. Increased blood pressure causes the heart to start failing in its physiological functions. Heart failure is the end result in this condition of increased blood pressures.
There is a significant increase in cholesterol in blood of people who are obese. High blood cholesterol levels causes the deposition of fats in various parts of the body and organs. Deposition of fats in the heart and blood vessels result in heart diseases. There are other conditions that result from hypercholesterolemia.
Other chronic illnesses like cancer can also arise from obesity because inflammation of body cells and tissues occurs in order to store fats in obese people. This could result in abnormal growths and alteration of cell morphology. The abnormal growths could be cancerous.
Management of Obesity:
For the people at risk of developing obesity, prevention methods can be implemented. Prevention included a healthy diet and physical activity. The diet and physical activity patterns should be regular and realizable to avoid strains that could result in complications.
Some risk factors for obesity are non-modifiable for example genetics. When a person in genetically predisposed, the lifestyle modifications may be have help.
For the individuals who are already obese, they can work on weight reduction through healthy diets and physical exercises.
In conclusion, obesity is indeed a major health concern because the health complications are very serious. Factors influencing obesity are both modifiable and non-modifiable. The management of obesity revolves around diet and physical activity and so it is important to remain fit.
In olden days, obesity used to affect only adults. However, in the present time, obesity has become a worldwide problem that hits the kids as well. Let’s find out the most prevalent causes of obesity.
Factors Causing Obesity:
Obesity can be due to genetic factors. If a person’s family has a history of obesity, chances are high that he/ she would also be affected by obesity, sooner or later in life.
The second reason is having a poor lifestyle. Now, there are a variety of factors that fall under the category of poor lifestyle. An excessive diet, i.e., eating more than you need is a definite way to attain the stage of obesity. Needless to say, the extra calories are changed into fat and cause obesity.
Junk foods, fried foods, refined foods with high fats and sugar are also responsible for causing obesity in both adults and kids. Lack of physical activity prevents the burning of extra calories, again, leading us all to the path of obesity.
But sometimes, there may also be some indirect causes of obesity. The secondary reasons could be related to our mental and psychological health. Depression, anxiety, stress, and emotional troubles are well-known factors of obesity.
Physical ailments such as hypothyroidism, ovarian cysts, and diabetes often complicate the physical condition and play a massive role in abnormal weight gain.
Moreover, certain medications, such as steroids, antidepressants, and contraceptive pills, have been seen interfering with the metabolic activities of the body. As a result, the long-term use of such drugs can cause obesity. Adding to that, regular consumption of alcohol and smoking are also connected to the condition of obesity.
Harmful Effects of Obesity:
On the surface, obesity may look like a single problem. But, in reality, it is the mother of several major health issues. Obesity simply means excessive fat depositing into our body including the arteries. The drastic consequence of such high cholesterol levels shows up in the form of heart attacks and other life-threatening cardiac troubles.
The fat deposition also hampers the elasticity of the arteries. That means obesity can cause havoc in our body by altering the blood pressure to an abnormal range. And this is just the tip of the iceberg. Obesity is known to create an endless list of problems.
In extreme cases, this disorder gives birth to acute diseases like diabetes and cancer. The weight gain due to obesity puts a lot of pressure on the bones of the body, especially of the legs. This, in turn, makes our bones weak and disturbs their smooth movement. A person suffering from obesity also has higher chances of developing infertility issues and sleep troubles.
Many obese people are seen to be struggling with breathing problems too. In the chronic form, the condition can grow into asthma. The psychological effects of obesity are another serious topic. You can say that obesity and depression form a loop. The more a person is obese, the worse is his/ her depression stage.
How to Control and Treat Obesity:
The simplest and most effective way, to begin with, is changing our diet. There are two factors to consider in the diet plan. First is what and what not to eat. Second is how much to eat.
If you really want to get rid of obesity, include more and more green vegetables in your diet. Spinach, beans, kale, broccoli, cauliflower, asparagus, etc., have enough vitamins and minerals and quite low calories. Other healthier options are mushrooms, pumpkin, beetroots, and sweet potatoes, etc.
Opt for fresh fruits, especially citrus fruits, and berries. Oranges, grapes, pomegranate, pineapple, cherries, strawberries, lime, and cranberries are good for the body. They have low sugar content and are also helpful in strengthening our immune system. Eating the whole fruits is a more preferable way in comparison to gulping the fruit juices. Fruits, when eaten whole, have more fibers and less sugar.
Consuming a big bowl of salad is also great for dealing with the obesity problem. A salad that includes fibrous foods such as carrots, radish, lettuce, tomatoes, works better at satiating the hunger pangs without the risk of weight gain.
A high protein diet of eggs, fish, lean meats, etc., is an excellent choice to get rid of obesity. Take enough of omega fatty acids. Remember to drink plenty of water. Keeping yourself hydrated is a smart way to avoid overeating. Water also helps in removing the toxins and excess fat from the body.
As much as possible, avoid fats, sugars, refined flours, and oily foods to keep the weight in control. Control your portion size. Replace the three heavy meals with small and frequent meals during the day. Snacking on sugarless smoothies, dry fruits, etc., is much recommended.
Regular exercise plays an indispensable role in tackling the obesity problem. Whenever possible, walk to the market, take stairs instead of a lift. Physical activity can be in any other form. It could be a favorite hobby like swimming, cycling, lawn tennis, or light jogging.
Meditation and yoga are quite powerful practices to drive away the stress, depression and thus, obesity. But in more serious cases, meeting a physician is the most appropriate strategy. Sometimes, the right medicines and surgical procedures are necessary to control the health condition.
Obesity is spreading like an epidemic, haunting both the adults and the kids. Although genetic factors and other physical ailments play a role, the problem is mostly caused by a reckless lifestyle.
By changing our way of living, we can surely take control of our health. In other words, it would be possible to eliminate the condition of obesity from our lives completely by leading a healthy lifestyle.
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- The science of obesity...
The science of obesity: what do we really know about what makes us fat? An essay by Gary Taubes
- Related content
- Peer review
- Gary Taubes , co-founder
- 1 Nutrition Science Initiative, San Diego, California , USA
The history of obesity research is a history of two competing hypotheses. Gary Taubes argues that the wrong hypothesis won out and that it is this hypothesis, along with substandard science, that has exacerbated the obesity crisis and the related chronic diseases. If we are to make any progress, he says, we have to look again at what really makes us fat
Since the 1950s, the conventional wisdom on obesity has been simple: it is fundamentally caused by or results from a net positive energy balance—another way of saying that we get fat because we overeat. We consume more energy than we expend. The conventional wisdom has also held, however, that efforts to cure the problem by inducing undereating or a negative energy balance—either by counselling patients to eat less or exercise more—are remarkably ineffective.
Put these two notions together and the result should be a palpable sense of cognitive dissonance. Take, for instance, The Handbook of Obesity , published in 1998 and edited by three of the most influential authorities in the field. “Dietary therapy,” it says, “remains the cornerstone of treatment and the reduction of energy intake continues to be the basis of successful weight reduction programs.” And yet it simultaneously describes the results of such dietary therapy as “poor and not long-lasting.” 1
Rather than resolve this dissonance by questioning our beliefs about the cause of obesity, the tendency is to blame the public (and obese patients implicitly) for not faithfully following our advice. And we embrace the relatively new assumption that obesity must be a multifactorial and complex disorder. This makes our failures to either treat the disorder or rein in the burgeoning epidemics of obesity worldwide somehow understandable, acceptable.
Another possibility, though, is that our fundamental understanding of the aetiology of the disorder is indeed incorrect, and this is the reason for the lack of progress. If this is true, and it certainly could be, then rectifying this aetiological misconception is absolutely critical to future progress.
Energy balance hypothesis
Despite its treatment as a gospel truth, as preordained by physical law, the energy balance or overeating hypothesis of obesity is only that, a hypothesis. It’s largely the product of the influential thinking of two physicians—the German diabetes specialist Carl von Noorden at the beginning of the 20th century, and the American internist and clinical investigator Louis Newburgh, a quarter century later. Its acceptance as dogma came about largely because its competing hypothesis—that obesity is a hormonal, regulatory disorder—was a German and Austrian hypothesis that was lost with the anti-German sentiment after the second world war and the subsequent embracing of English, rather than German, as the lingua franca of science.
Medicine today is often taught untethered from its history—unlike physics, for instance—which explains why the provenance of the energy balance hypothesis is little known, even by those physicians and researchers who are its diehard proponents. Nor is it widely known that a competing hypothesis ever existed, and that this hypothesis may have done a better job of explaining the data and the observations. Knowing this history is crucial to understanding how we got into the current situation and, indeed, how we might solve it.
The applicability of the laws of thermodynamics to living organisms dates from the 1880s and the research of the German physiologist Max Rubner. By the end of the 19th century, the American scientists Wilbur Atwater and Francis Benedict had confirmed that these laws held for humans as well: that the calories we consumed would be burned as fuel, stored, or excreted. 2 This revelation then led von Noorden to propose that “the ingestion of a quantity of food greater than that required by the body, leads to an accumulation of fat, and to obesity, should the disproportion be continued over a considerable period.” 3
By the late 1920s, Newburgh had taken up the energy balance banner at the University of Michigan and was promoting it based on what he believed to be a fundamental truth: “All obese persons are alike in one fundamental respect—they literally overeat.” As such, he blamed obesity on either a “perverted appetite” (excessive energy consumption) or a “lessened outflow of energy” (insufficient expenditure). 4 If the obese person’s metabolism was normal, he argued, and they still refused to rein in their intake, that was sufficient evidence to assume that they were guilty of “various human weaknesses such as overindulgence and ignorance.” 5
By 1939, Newburgh’s biography at the University of Michigan was crediting him with the discovery that “the whole problem of weight lies in regulation of the inflow and outflow of calories” and for having “undermined conclusively the generally held theory that obesity is the result of some fundamental fault.” 6
As sceptics pointed out at the time, though, the energy balance notion has an obvious flaw: it is tautological. If we get fatter (more massive), we have to take in more calories than we expend—that’s what the laws of thermodynamics dictate—and so we must be overeating during this fattening process. But this tells us nothing about cause. Here’s the circular logic:
Why do we get fat? Because we overeat.
How do we know we’re overeating? Because we’re getting fatter.
And why are we getting fatter? Because we’re overeating.
And so it goes, round and round.
“The statement that primary increase of appetite may be a cause of obesity does not lead us very far,” wrote the Northwestern University School of Medicine endocrinologist Hugo Rony in 1940 in Obesity and Leanness , “unless it is supplemented with some information concerning the origin of the primarily increased appetite. What is wrong with the mechanism that normally adjusts appetite to caloric output? What part of this mechanism is primarily disturbed?” Any regulatory defect that drove people to gain weight, Rony noted, would induce them to take in more calories than they expend. “Positive caloric balance would be, then, a result rather than a cause of the condition.” 7
The alternative hypothesis that Newburgh’s work had allegedly undermined was the idea that some “intrinsic abnormality”—Rony’s words—was at the root of the disorder. This was an endocrinological hypothesis. It took the laws of physics as a given; it rejected aberrant behaviour or ignorance as causal. It existed at the time as two distinct hypotheses.
One was the brainchild of Wilhelm Falta, a student of von Noorden and a pioneer of the science of endocrinology. Falta believed that the hormone insulin must be driving obesity on the basis, as he noted as early as 1923, that “a functionally intact pancreas is necessary for fattening.” 8 Once insulin was discovered, Falta considered it the prime suspect in obesity. “We can conceive,” he wrote, “that the origin of obesity may receive an impetus through a primarily strengthened function of the insular apparatus, in that the assimilation of larger amounts of food goes on abnormally easily, and hence there does not occur the setting free of the reactions that in normal individuals work against an ingestion of food which for a long time supersedes the need.” 9
The other version of the hypothesis was bound up in a concept known as lipophilia. It was initially proposed in 1908 by Gustav Von Bergmann, a German authority on internal medicine, and then taken up by Julius Bauer, who did pioneering work on endocrinology, genetics, and chronic disease at the University of Vienna.
Von Bergmann initially evoked the term lipophilia (“love of fat”) to explain why fat deposition was not uniform throughout the body. Just as we grow hair in some places and not others, according to this thinking, we fatten in some areas and not others and biological factors must regulate this. People who are constitutionally predisposed to fatten, Von Bergmann proposed, had adipose tissue that was more lipophilic than that of constitutionally lean individuals. And if fat cells were accumulating excessive calories as fat, this would deprive other organs and cells of the energy they needed to thrive, leading to hunger or lethargy. These would be compensatory effects of the fattening process, not causes.
“Like a malignant tumor or like the fetus, the uterus or the breasts of a pregnant woman,” explained Bauer, “the abnormal lipophilic tissue seizes on foodstuffs, even in the case of undernutrition. It maintains its stock, and may increase it independent of the requirements of the organism. A sort of anarchy exists; the adipose tissue lives for itself and does not fit into the precisely regulated management of the whole organism.” 10
Erich Grafe, director of the Clinic of Medicine and Neurology at the University of Würtzberg, discussed these competing hypotheses in his seminal textbook Metabolic Diseases and Their Treatment, which was published in an English translation in 1933. Grafe said he favoured the energy balance model of obesity, but acknowledged that this model failed to explain key observations—why fat accumulates in certain regions of the body. “The energy conception certainly cannot be applied to this realm,” Grafe wrote. The lipophilia hypothesis could.
Grafe described lipophilia as “a condition of abnormally facilitated fat production and impeded fat destruction . . . a sort of lipomatosis universalis , in the sense that the lipophilia in certain tissues is primary and the sparing in the energy expended is secondary.” But he found the hypothesis troubling “so far as it presupposes overnutrition.” He acknowledged, nonetheless, that it was “a good working hypothesis.” As for Falta’s notions, Grafe wrote, “the fact that insulin is an excellent fattening substance has been observed.” 11
By 1938, Russell Wilder of the Mayo Clinic (later to become director of the National Institute of Arthritis and Metabolic Diseases) was writing that the lipophilia hypothesis “deserves attentive consideration,” and that “the effect after meals of withdrawing from the circulation even a little more fat than usual might well account both for the delayed sense of satiety and for the frequently abnormal taste for carbohydrate encountered in obese persons . . . A slight tendency in this direction would have a profound effect in the course of time.” 12
Two years later, Rony wrote in Obesity and Leanness that the hypothesis was “more or less fully accepted” in Europe.
Maybe so. But it was lost with the second world war and the embracing of English as the lingua franca of science afterwards. In Grafe’s chapters on obesity, over 90% of the 235 references are from the German language literature. In Rony’s Obesity and Leanness , this is true for a third of the almost 600 references. But post-war, the German language references fall away quickly. In Obesity… , published in 1949 by two Mayo Clinic physicians—Edward Rynearson and Clifford Gastineau—only 14 of its 422 references are from the German language literature, compared with a dozen from Louis Newburgh alone. By the late 1960s and 1970s, when the next generation of textbooks were written, German language references were absent almost entirely, as were the clinical observations, experience, and intuitions that went with them.
By then, obesity had evolved into an eating disorder, to be treated and studied by psychologists and psychiatrists, while laboratory researchers focused (as they still do) on identifying the physiological determinants of hunger, satiety, and appetite: why do we eat too much, rather than why do we store too much fat? Two entirely different questions.
What makes this transition so jarring in retrospect is that it coincided with the identification of the hormone insulin in the early 1960s as the primary regulator of fat accumulation in fat cells. 13 Had Falta’s ideas and the lipophilia hypothesis survived the second world war, this discovery would have served to bring these two hypotheses together. And because serum insulin levels are effectively driven by the carbohydrate content of the diet, this hypothesis would implicate refined, high glycaemic grains and sugars (sucrose and high fructose corn syrup, in particular) as the environmental triggers of obesity. They would be considered uniquely fattening, just as Falta had suggested, not because we overeat them—whatever that means—but because they trigger a hormonal response that drives the partitioning of the fuel consumed into storage as fat.
This might have been perceived, although it was not, as a medical triumph: the elucidation of both the biological underpinnings of obesity as well as an explanation for what was until then the conventional wisdom on the cause. “Every woman knows that carbohydrate is fattening,” as Reginald Passmore and Yola Swindells wrote in the British Journal of Nutrition in 1963: “this is a piece of common knowledge, which few nutritionists would dispute.” 14
That this insulin-carbohydrate hypothesis never gained traction can be explained, paradoxically, by the fact that it was embraced by practising physicians, who read the physiology and biochemistry literature and then designed carbohydrate restricted diet plans that seemed to work remarkably well. Indeed, the sessions on dietary therapy for obesity in the scattering of obesity conferences held from the end of the second world war through the mid-1970s invariably focused on the surprising efficacy of carbohydrate restricted diets to reduce excess adiposity.
When those physicians then wrote diet books based on their regimens, and these books then sold exceedingly well— Dr Atkins’ Diet Revolution (1972) most notably—the result was a backlash from academic nutritionists and obesity researchers. Fred Stare, for instance, head of the Harvard nutrition department, testified in 1972 Congressional hearings that physicians prescribing such diets were “guilty of malpractice,” on the basis that these diets were rich in saturated fat at a time when the medical community was coming to believe that high fat diets were the cause of heart disease. Exacerbating the dietary fat issue was the fact that these diet plans encouraged obese individuals to eat to satiety, effectively as much as they wanted (so long as they avoided carbohydrates), when the conventional wisdom had it that they got fat to begin with precisely because they ate as much as they wanted.
By the mid-1970s, the diets had been successfully tarred as dangerous fads (despite a history of common use in hospitals, including the Harvard Medical School, 15 and a provenance going back at least to the 1820s) and the physician authors as quacks and confidence men. The notion that obesity is not an eating disorder or an energy balance disorder, but a fat accumulation disorder—a hormonal, regulatory disorder—triggered not by energy imbalance but the quality and quantity of the carbohydrates in the diet, has been routinely dismissed ever since as unworthy of serious attention.
In a 21st century of genomics, proteomics, and high tech medicine, it’s hard to imagine that the obesity problem might have been effectively solved by 1960s era endocrinology. Rather we assume that these competing hypotheses must have been rigorously tested, and the energy balance hypothesis must have won out. We know that it’s excess calories, not carbohydrates—eating too much rather than “abnormal lipophilic tissue”—that make us fat because that’s what the science has told us.
But this is not the case. One problem has been an almost ubiquitous misunderstanding of the alternative hypothesis and, indeed, of energy imbalance itself. The existence of an energy imbalance in people who are getting fatter is treated, as Newburgh did, as evidence that the energy balance hypothesis is correct. The same can be said for observations that obese people eat more than lean or are more sedentary, or even that per capita food availability has increased over the course of the obesity epidemic or that leisure time physical activity has decreased. All these observations, though, are consistent with both hypotheses.
Calories or carbohydrates
Attempts to blame the obesity epidemics worldwide on increased availability of calories typically ignore the fact that these increases are largely carbohydrates and those carbohydrates are largely sugars—sucrose or high fructose corn syrup. And so these observations shed no light on whether it’s total calories to blame or the carbohydrate calories. Nor do they shed light on the more fundamental question of whether people or populations get fat because they’re eating more, or eat more because the macronutrient composition of their diets is promoting fat accumulation—increased lipogenesis or decreased lipolysis, in effect, driving an increase in appetite.
The same is true for bariatric surgery, which is now acknowledged to be a remarkably effective means of inducing long term weight loss. But does weight loss occur after surgery because of the rearrangement of the gastrointestinal tract resulting in hormonal effects that minimise appetite or directly minimise fat accumulation? Does it occur because the patient reduces total calories consumed after surgery or reduces carbohydrate calories and, specifically, refined grains and sugars? The observation that bariatric surgery works doesn’t answer these questions.
As Erich Grafe noted about the lipophilia hypothesis 80 years ago, it “presupposes overnutrition.” If a patient is getting heavier, they must be taking in more energy than they expend. With the energy balance hypothesis, overnutrition is causal; with lipophilia, it’s compensatory, a response to the hormonally driven fat accumulation. Either way, it has to exist while an individual is gaining weight. And, by the same token, undernutrition or negative energy balance has to exist if an individual is losing weight.
Sugary beverages are another example of how these different hypotheses lead to different conclusions that are relevant to solving the obesity epidemics worldwide. The conventional wisdom has it that sugary beverages are merely empty calories that we consume in excess, although it is possible that the metabolism of fructose (a key carbohydrate component that makes these sugars sweet) in the liver somehow circumvents leptin signalling, leading us to consume these beverages and their calories even when we’re not and shouldn’t be hungry. The hormonal or regulatory hypothesis also focuses on the metabolism of fructose in the liver, but rather than leptin it uses evidence suggesting that fructose metabolism can induce insulin resistance, leading in turn to raised insulin levels and trapping fat in fat cells—increasing, in effect, lipophilia.
Shortcomings of obesity and nutrition research
Another problem endemic to obesity and nutrition research since the second world war has been the assumption that poorly controlled experiments and observational studies are sufficient basis on which to form beliefs and promulgate public health guidelines. This is rationalised by the fact that it’s exceedingly difficult (and inordinately expensive) to do better science when dealing with humans and long term chronic diseases. This may be true, but it doesn’t negate the fact the evidence generated from this research is inherently incapable of establishing reliable knowledge.
The shortcomings of observational studies are obvious and should not be controversial. These studies, regardless of their size or number, only indicate associations—providing hypothesis generating data—not causal relations. These hypotheses then have to be rigorously tested. This is the core of the scientific process. Without rigorous experimental tests, we know nothing meaningful about the cause of the disease states we’re studying or about the therapies that might work to ameliorate them. All we have are speculations.
As for the experimental trials, these too have been flawed. Most conspicuous is the failure to control variables, particularly in free-living trials. Researchers counsel participants to eat diets of different macronutrient composition—a low fat, a low carbohydrate, and a Mediterranean diet, for instance—and then send them off about their lives to do so. In these trials, carbohydrate restricted diets almost invariably show significantly better short term weight loss, despite allowing participants to eat as much as they want and being compared with calorie restricted diets that also reduce the quantity of carbohydrates consumed and improve the quality. In these trials, the ad libitum carbohydrate restricted diets have also improved heart disease and diabetes risk factors better than the diets to which they’ve been compared. But after a year or two, the results converge towards non-significance, while attempts to quantify what participants actually eat consistently conclude that there is little long term compliance with any of the diets. 16 17 18
Rather than acknowledge that these trials are incapable of answering the question of what causes obesity (assumed to be obvious, in any case), this research is still treated as relevant, at least, to the question of what diet works best to resolve it—and that in turn as relevant to the causality question. Should we restrict calories or carbohydrates to lose weight? If the answer is that it doesn’t seem to matter because the participants eventually fail to adhere to any of the diets, this is perceived as somehow a confirmation that the only way to lose weight is to reduce calories, and so the energy balance hypothesis is the correct one. 19
Imagine drawing conclusions about the cause of lung cancer or the reduction in risk that can be achieved by quitting cigarettes based on success rates in experimental trials of smoking cessation techniques—going cold turkey, for instance, versus using the patch or nicotine gum. The logic is similar if not identical.
Ultimately what we want to know is what causes weight gain. That’s an entirely different question from whether advising someone to follow a Mediterranean diet is more or less efficacious than a low fat or a carbohydrate restricted diet or some variation thereof.
In metabolic ward studies, in which the diets of the participants have been well controlled, researchers typically restricted the calories in both arms of the trials—feeding participants, say, 800 calories of a low fat versus a low carbohydrate diet—and so building into the study design one of the hypotheses that is ultimately being tested. What we want to know, again, is what causes us to gain weight, not whether weight loss can be induced under different conditions of both semistarvation and carbohydrate restriction.
What can we do about this? It seems we have two choices. We can continue to examine and debate the past, or we can look forward and start anew.
A year ago, working with Peter Attia, a physician, and with support from the Laura and John Arnold Foundation in Houston Texas, I cofounded a not-for-profit organisation called the Nutrition Science Initiative (NuSI.org). Our strategy is to fund and facilitate rigorously well controlled experimental trials, carried out by independent, sceptical researchers. The Arnold Foundation has now committed $40m over the next three years to this research programme. Our hope is that these experiments will be the first steps in answering definitively the question of what causes obesity and help us finally make meaningful progress against it.
We believe that ultimately three conditions are necessary to make progress in the struggle against obesity and its related chronic diseases—type 2 diabetes, most notably. First is the acceptance of the existence of an alternative hypothesis of obesity, or even multiple alternative hypotheses, with the understanding that these, too, adhere to the laws of physics and must be tested rigorously.
Second is a refusal to accept substandard science as sufficient to establish reliable knowledge, let alone for public health guidelines. When the results of studies are published, the authors must be brutally honest about the possible shortcomings and all reasonable alternative explanations for what they observed. “If science is to progress,” as the Nobel prize winning physicist Richard Feynman said half a century ago, “what we need is the ability to experiment, honesty in reporting results—the results must be reported without somebody saying what they would like the results to have been—and finally—an important thing—the intelligence to interpret the results. An important point about this intelligence is that it should not be sure ahead of time what must be.” 20
Finally, if the best we’ve done so far isn’t good enough—if uncontrolled experiments and observational studies are unreliable, which should be undeniable—then we have to find the willingness and the resources to do better. With the burden of obesity now estimated at greater than $150bn (£100bn; €118bn) a year in the US alone, virtually any amount of money spent on getting nutrition research right can be defended on the basis that the long term savings to the healthcare system and to the health of individuals will offset the costs of the research by orders of magnitude.
Gary Taubes is cofounder of the Nutrition Science Initiative (NuSI.org), and an award-winning science and health journalist. He is the recipient of a Robert Wood Johnson Foundation Investigator Award in Health Policy Research and the author of Why We Get Fat and What to Do About It (Knopf, 2011) and Good Calories, Bad Calories: Fats, Carbs, and the Controversial Science of Diet and Health (Knopf, 2007), published in the UK as The Diet Delusion (see BMJ 2009;339:b5604) . He lives in Oakland, California.
Cite this as: BMJ 2013;346:f1050
Competing interests: I have read and understood the BMJ Group policy on declaration of interests and declare: I am employed by the Nutrition Science Initiative, a 501(3)c. NuSI does not accept support from the food industry. I received support (a book advance) from Random House Inc to do the research that is reported in this essay, and I have received honorariums and travel expenses from food industry and academic sources.
Provenance and peer review: Commissioned; not externally peer reviewed.
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A systematic literature review on obesity: Understanding the causes & consequences of obesity and reviewing various machine learning approaches used to predict obesity
- 1 Centre for Software Technology and Management, Faculty of Information Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia.
- 2 Centre for Software Technology and Management, Faculty of Information Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia. Electronic address: [email protected].
- 3 RIADI Laboratory, University of Manouba, Manouba, Tunisia; College of Computer Science and Engineering, Taibah University, Medina, Saudi Arabia.
- 4 Center for Artificial Intelligence Technology, Faculty of Information Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia.
- PMID: 34426171
- DOI: 10.1016/j.compbiomed.2021.104754
Obesity is considered a principal public health concern and ranked as the fifth foremost reason for death globally. Overweight and obesity are one of the main lifestyle illnesses that leads to further health concerns and contributes to numerous chronic diseases, including cancers, diabetes, metabolic syndrome, and cardiovascular diseases. The World Health Organization also predicted that 30% of death in the world will be initiated with lifestyle diseases in 2030 and can be stopped through the suitable identification and addressing of associated risk factors and behavioral involvement policies. Thus, detecting and diagnosing obesity as early as possible is crucial. Therefore, the machine learning approach is a promising solution to early predictions of obesity and the risk of overweight because it can offer quick, immediate, and accurate identification of risk factors and condition likelihoods. The present study conducted a systematic literature review to examine obesity research and machine learning techniques for the prevention and treatment of obesity from 2010 to 2020. Accordingly, 93 papers are identified from the review articles as primary studies from an initial pool of over 700 papers addressing obesity. Consequently, this study initially recognized the significant potential factors that influence and cause adult obesity. Next, the main diseases and health consequences of obesity and overweight are investigated. Ultimately, this study recognized the machine learning methods that can be used for the prediction of obesity. Finally, this study seeks to support decision-makers looking to understand the impact of obesity on health in the general population and identify outcomes that can be used to guide health authorities and public health to further mitigate threats and effectively guide obese people globally.
Keywords: Diseases; Machine learning; Obesity; Overweight; Risk factors.
Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.
- Research Support, Non-U.S. Gov't
- Systematic Review
- Machine Learning
- Metabolic Syndrome*
- Obesity* / epidemiology
- Risk Factors