In this article we’ll give our point view on the main causes of obesity based on evidence obtained by researchers who have worked and continue to work hard to clarify the truth about this very controversial topic in our society.


Unfortunately, it is very common to see that most members of society, regardless of their nationality, race, gender or cultural level look at the obese person as someone that suffers from this condition because of their own fault.


Personally, again based on evidence, it seems incredible that being on the 21st century there is such level of ignorance (including some people in the medical field) about the causes of obesity which go far beyond being lazy, undisciplined or making bad eating decisions.


When the obese patient becomes aware of his situation and it is truly determined and committed to a change in their lifestyle, unfortunately usually this commitment is not enough to reach a healthy weight or if he/she achieves it, is extremely difficult to maintain that weight.


This is the story of 90% of our patients and based on our experience we can say with certainty that those who are in this situation have gone through countless efforts and challenges in search to permanently change their situation and if they decide to undergo a surgical procedure is because they have exhausted all other options and have been trying for years or even decades.


Many non-obese persons often consider bariatric surgery as an easy way out and judge the bariatric patient wrongfully by ignoring the huge difficulty that represents to maintain a healthy weight despite giving their best effort. It's easy to judge based on beliefs or personal experiences, but those who do succeed are people who really were not genetically doomed to be obese and their problem was more related to attitude toward their lifestyle than to a genetically determined problem.


The obese patient usually suffers for this condition, even in everyday "simple" activities such as buckling up the car or airplane seat belt, tying their shoelaces, going grocery shopping, standing in line at the bank, walking short distances, exercising, etc; These activities are so difficult for them that many choose to avoid them because they represent both a physical and psychological challenge.


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Why do we say that this psychologically affects them? We as a society, globally, tend to discriminate against obese persons, they are teased at school, they are prejudged and people assume that their condition is due to improper lifestyle, poor eating habits and lack of commitment to themselves, being judged that way for years can dramatically undermine a person’s self-esteem.


After decades of medical research, it has been found that although bad eating habits and a sedentary lifestyle are definitely causes of obesity in some cases, most cases of obesity have a much more complex explanation, so much that to date it has not been able to determine all the factors involved in the biology of obesity.


Interestingly enough, did you know that children born from obese mothers are more prone to obesity in their adult life and that children born (siblings of the previous) from post operated mothers of bariatric surgery reduce that risk? It sounds like something taken out of science fiction but it is proven data obtained after years of research in this topic.


Here we explain in simple terms what is known up to date on the biology of obesity and why a person develops it.


Content of this article:
The influence of Evolution in obesity
The influence of the Gastrointestinal Tract in obesity
Influence of Drugs in obesity
The influence of Diseases in obesity
Influence of Environment on obesity
The Influence of Emotional Factors in obesity
The influence of Age on Obesity
The influence of Pregnancy in obesity
The influence of Lack of Sleep in obesity



The influence of Evolution in obesity

There is a widespread misconception that obesity solely develops due to a chronic state of excess food (energy) and low physical activity (low-energy) resulting in an accumulation of excess calories as body fat.


However, this simplistic view does not take into account there are many factors that determine what we eat (sociocultural and economic level), how active we are physically and how our bodies process energy and adapt to changes in availability and energy expense.


Here we must consider human evolutionary context of how the procurement of food is essential to life. The desire for food is one of the most powerful behaviors in the human and the animal kingdom and is fundamental to the preservation of our species.


There are many body systems that control our food intake and our weight. These biological determinants have been changing over the centuries and has brought the hypothesis that there are “thrifty” genes who have been favored due to higher survival and fecundity conferred on individuals with these genes when resources are scarce.


These genes are counterproductive in our times since they favour the accumulation of excess body fat as a way of preparing to starvation states that never come and the result is precisely obesity.


However, the high prevalence of people with normal weight in an obesogenic environment suggests another hypothesis such as the “drifty” gene hypothesis; trying to explain in simple terms, suggests that the tendency to develop obesity is not because of human adaptation to starvation states but that with the passage of centuries the risk of predation has been disappearing so there have been genetic changes that have gradually led to a negative selection of predisposing factors for obesity.


This lower risk of falling prey to a predator causes random genetic changes that have affected our energy control systems and over time have become more numerous and prevalent resulting in a genetic susceptibility to obesity. This, coupled with the undoubted and dramatic changes in the availability of food and sedentary lifestyles have favored this genetic susceptibility.


There’s also the hypothesis since 2007 on changes in the FTO gene which is strongly linked to increases in body mass index, this gene has been considered the “obesity gene”. These variations occur with the passage of decades and are influenced by the environment.


There are many hypotheses which relate genetic obesity, yet there is no theory so far, what is known is that it is not only one genetic factor involved, but many of them come into play to predispose a person to develop obesity.



The influence of the Gastrointestinal Tract in obesity

In recent years the role of the gastrointestinal tract as the largest endocrine organ in the body has emerged strongly. The cells of the gastrointestinal tract (GI, abbreviated) called enter-endocrine cells produce hormones that play an important role in regulating body weight. These hormones act through a complex neuroendocrine system involving the hypothalamus and reward centers of the brain to regulate energy balance.


In obesity there is evidence that the balance in the GI-brain tract is lost either by changes in levels of circulating hormones or by an alteration in the homeostatic response centers (hormonal balance) of the brain.


Explaining in detail the regulatory systems of these hormones does not make much sense but I think therein lies much of the answer to why a person is doomed to obesity if it does not make drastic changes in their body and that is achieved with bariatric surgery.


Some of the hormones involved are YY peptide, GLP-1 peptide, leptin and ghrelin hormone which stimulates appetite by acting in key brain regions responsible for controlling food and reward, this hormone is produced by stomach cells and is one of the major physiological explanations of why the great effectiveness of bariatric procedures such as gastric bypass and gastric sleeve in reducing the intensity and frequency of appetite.


Like these major factors, many others are involved in the susceptibility to obesity, some other examples are:


Influence of Drugs in obesity

Some medications can be a cause of obesity or weight gain, some examples include antidepressants, anticonvulsants or antiepileptics and corticosteroids.


The influence of Diseases in obesity

Some hormonal diseases cause overweight and obesity, including hypothyroidism, Cushing's syndrome and polycystic ovarian syndrome (PCOS).


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Influence of Environment on obesity

On this subject we could develop a complete new article, in short, almost everything around us in today's world pushes us consciously or unconsciously to gain weight.


Simple things that we disregard such as the lack of adequate exercise areas whether public or private (usually very expensive), long working hours that leave us little time to exercise, advertising that encourages us to eat, very big food portions on restaurants, etc.


It is important however, that each one of us should recognize that these environmental factors affect us only if we allow it.


The Influence of Emotional Factors in obesity

It is very common for the obese patient falling into a vicious circle in which food is their "exit" for emotions like anger, sadness, excitement, etc.


The influence of Age on Obesity

It is well known that as an individual grows older its metabolism tends to be increasingly slower. It is said that after age 35, for example, even if the person does not make changes in their physical activity or their eating habits, yet it is destined to raise around 2 pounds per year.


This situation can be reversed or effectively addressed if the person has the habit of exercising regularly as this will prevent their metabolism’s tendency to decrease.


The influence of Pregnancy in obesity

Pregnancy is a natural and physiological form of weight gain and I truly believe that should not be an excuse to gain weight to a degree that after pregnancy the mother cannot lose that excess weight almost entirely. We discussed extensively about this topic in our article on gastric sleeve and pregnancy.


The influence of Lack of Sleep in obesity

Research shows that lack of sleep causes a person to have cravings for high calorie index food, sleep helps maintain a proper balance of hormones involved in appetite as ghrelin or leptin.


When not sleeping enough, ghrelin levels rise, so the sensation of appetite is increased. There has been a link between lack of sleep and lack of effectiveness of insulin in the body which in the long term could also be associated with an increased risk of developing diabetes.



Treatment of obesity

Without diving deep into the topic we can therefore say that proper management of obesity is much more complex than simply eating less and being more active, there is evidence that even with measures such as restricting calorie intake and intervention programs in the lifestyle of the patient including diet, exercise and psychological support it may be effective in the short term, in the long term unfortunately, the vast majority of patients regain the lost weight.


At present, the pharmacological treatment of obesity has not achieved the expected results and often these drugs have been recalled due to the increase in severe adverse side effects such as psychiatric disorders or cardiovascular effects. And those who are accepted and are available, show a loss of excess body weight of only around 3 to 9%.


Finally, metabolic and bariatric surgery has been shown to be an effective treatment for obesity achieving durable weight loss of 50 to 75% of the excess weight depending of the procedure, a significant improvement in the control or even cure of deteriorating obesity related diseases. The American Diabetes Association has agreed that bariatric surgery is the only occasional cure that currently exists for type 2 diabetes.


To date, metabolic and bariatric surgery is the only treatment considered effective in patients with severe obesity and its positive effects are lasting and significant in the long term. That's why bariatric procedures worldwide have been increasing in recent decades in patients who are candidates for bariatric surgery being the most frequently performed the gastric bypass, gastric sleeve and gastric band surgery.


If by any chance you are reading this and you are not obese we invite you to deeply ponder on what we have just explained in order that next time you see an obese person keep in mind that we can’t be judgmental and assume that their problem is only their fault .


We need to be empathetic as we would be with a person who is sick with any another disease than obesity and be aware that there may be many other factors behind their condition.

Your turn, post your comments if you have plans on having surgery or if you had it done and what has been your experience and results.


The gastric sleeve procedure in México is totally safe, we invite you to get a free evaluation with us and share your questions about the gastric sleeve cost in México, side effects, etc.



Written by: Gabriel Rosales

Dr. Gabriel Rosales is a highly skilled, board certified surgeon in constant pursuit of learning the latest innovations in the weight loss surgery field to give his patients the best care possible.