The body circle of overweight and obesity
“These days, when we all put on a few kilos, the key is not focused on whether overweight and obese people have this accumulation of fat simply because they like to eat and eat; no. It is very important to know that some people gain weight more than others because of their genetics”, says Dr. Enric de Madaria Pascual, gastroenterologist at the General University Hospital ‘Doctor Balmis’ in Alicante.
Our body regulates the amount of fat stored by controlling sensations such as hunger or satiety, the feeling of pleasure in eating and the amount of energy we expend.
“It always aims to reach a balance, that is, a body fat situation, let’s say idealfor each individual, which does not have to coincide with the external perception of our own image”, emphasizes Dr. de Madaria, president, in turn, of the Spanish Association of Gastroenterology.
The problem is particularly focused on some people: “This balance, this amount of fat that is part of each person, can lead to overweight or obesity”, he explains.
The type of diet we eat and the lack of physical exercise also undoubtedly influence.
“The amount of fat that the body considers normal, together with unhealthy lifestyle habits (diet, drinking, alcohol, smoking, sedentary lifestyle, etc.), can determine a greater overweight or obesity”, he emphasizes and gives an example:
“Imagine two people who are 170 cm tall; one has its balance at 65 kg and another at 100 kg. When they become thinner, the body will react to return to the usual equilibrium situation. Your body will tend to be at this weight level ideal“.
Hereditary factors that make us gain weight
The cells that store body fat are called adipocytes. These cells accumulate fat inside them, energy, and make up adipose or fatty tissue. White adipocytes, very present in adult humans, contain lipids that practically occupy the entire interior of the cell.
Knowing this function of adipocytes, among others, they have studied, for example, weight patterns in genetically identical twins.
“The results of different studies indicate that between 40 and 75% of the amount of accumulated fat is due to genetic inheritance. This fact is observed, even, if the twins are raised in different homes, that is to say, with different eating habits”, points out Dr. from Madaria.
Also, children adopted by other non-biological mothers or fathers tend to have the same amount of fat as the biological parents.
“In fact, they have been identified, for now, 500 hereditary factors that influence our fat deposits: they modulate our body’s response when we eat too much or face a prolonged fast; likewise, when faced with energy consumption, the food we prefer, the feeling of hunger or satiety”, he relates.
Even so, genes being of utmost importance, more cases of obesity are now being recorded and treated than before, as we consume more sugary foods and generally do less physical exercise (static office work, screens multi-use, electronic devices applied to interpersonal communications, plus motorized transport (bicycles and scooters).
“And the younger you are when exposed to these environmental factors (childhood and adolescence), the more likely you are to suffer obesity; probably originated by changing the amount of fat that our body judges as adequate”, observes the gastroenterologist.
Which genes favor the storage of body fat?
Most common obesity is supported by many different genes, but there are two large groups of genes directly involved.
“The genes that regulate whether we have more or less weight, closely related to the circuits that organize the energy balance at brain level; and the genes that structure the distribution of fat in the body, more related to the functioning of fat cells or adipocytes”, he explains.
An example would be the FTO gene, of which there are mutations.
“Variants of this gene predispose to greater use of fat reserves, so that adipocytes burn more energy; on the contrary, some of these mutations favor the storage of fat, a genetic argument for the individual to gain weight”, he indicates.
So much so that a single mutation in a gene is associated with obesity in certain rare diseases.
“An example is Prader-Willi syndrome. The lack of a gene produces a series of clinical manifestations, among which it stands out suffering from a very intense hunger that makes these people, already from their childhood, eat compulsively and systematically gain weight”, refers the specialist to pathologies of the pancreas.
Doctor, How does our body avoid gaining and gaining kilos?
It is very difficult for the overweight or obese human being to lose pounds and stay slimmer.
With a proper diet and some lifestyle changes you will lose weight over six to nine months; then this weight loss will be maintained over another period of time only to gain weight again.
The body reacts by altering the balance between consumption and expenditure: it increases the need for consumption, increasing the sensation of hunger, and decreases energy expenditure by lowering the speed of our metabolism, consuming less.
Many body responses are genetically determined. Brain structures therefore integrate hormonal messages arriving from adipocytes, the digestive system, endocrine organs and the liver.
The brain integrates it all together with behavioral responses such as pleasure, self-control and impulsivity.
The brain not only produces the sensation of hunger and satiety, but also determines how much stored energy is consumed.
Enric de Madaria Pascual, gastroenterologist
And what role do our hormones play in overweight and obesity?
First we highlight the leptinwhich is a very interesting hormone, linked to the body’s reaction to weight loss.
Leptin, which always informs the brain, is produced by adipocytes, so the more body fat we have, the more leptin there will be in the blood.
“If we lose fat and leptin drops, from a certain threshold the body interprets that we are losing too much weight and reacts by increasing our sense of hunger, so our metabolism decreases to expend less energy and we tend to to regain the lost weight”, he points out.
“Leptin increases the feeling of hunger if its level is low, to get us to eat more and lower energy expenditure and not keep losing weight”, he adds.
Therefore, the key to this hormone is to make it difficult to lose weight and encourage weight gain again.
“The level of weight reduction to which this response is triggered, by lowering leptin, seems to be very important in determining the weight that each person will tend to register throughout their life”, he completes.
“The brain reacts to the drop in leptin at different thresholds, so that for some people it determines that they weigh more and for others less”, he adds.
Another hormone involved is the ghrelin, produced by the stomach and duodenum. Unlike leptin, it stimulates appetite when it is high in the blood.
“It takes off when we think about eating and decreases when eating, when the stomach is filled with food. It increases when we diet or exercise and lose weight, and it’s another mechanism that makes it difficult for us to keep the weight we’ve lost,” he says.
In any case, changes in the daily energy we spend are fundamental in the body’s reaction to weight loss.
Losing weight reduces daily energy expenditure by up to 30%, and this metabolic reduction is maintained in the long term as long as we remain thin.
Are we doomed to get fat and can we just starve ourselves to be thin?
“We all have a level of fat deposits that our body considers normal (ideal), and often this characteristic will determine our overweight and obesity, when the case comes”, reinforces Dr. Enrique de Madaria.
This process makes it very difficult, therefore, to lose weight, “but it is healthy to do it” – he insists. Getting closer to our structural (ideal) weight will always have a reward of health benefits.
“It is essential that we know this organic functioning, since losing weight in a sustained way is not simply a matter of will. Our body will fight with all its might to recover the lost weight and in most cases this will happen without us being able to do practically anything in the medium and long term”, he specifies.
And which diseases are related to overweight and obesity?
Obesity is associated with diabetes, hypertension, hypercholesterolemia, heart disease, sleep apnea, incontinence, depression, among other pathologies, and a lower overall quality of life.
Overweight without cardiovascular disease or diabetes is treated with diet and exercise, changing long-term habits and, above all, trying not to gain more weight.
“In the case of overweight or obesity associated with diseases, if the previously reviewed measures are not sufficient, it will be advisable to add medicines that help to lose weight. The aim is to reduce body weight by at least 5%”, he advises.
If this strategy fails, and the obesity case is relevant, bariatric surgery will be considered.
“It forms a series of surgical techniques that help to lose weight by reducing the volume of the stomach or modifying the anatomy of the intestine and biliopancreatic secretions so that the patient absorbs less nutrients and they are lost in the stool,” he explains.
“Bariatric surgery is by far the most effective method of losing weight; but it is also the most aggressive and can be associated with complications”, warns Dr. Enrique de Madaria.
Recommendation for the “comilones” of Christmas
“There is only one Christmas and I think we should take advantage of the designated holidays to enjoy the delicious food and drinks. Of course, the rest of the non-holiday days we will have to show moderation to keep the necessary balance; an essential medicine in any field of Medicine”.
“We all deserve to enjoy Christmas with our family and friends, even more so after the covid pandemic that has threatened us since the end of 2019… and in January 2023 to practice daily physical exercise adapted to each age”.
Dr. Enrique de Madaria Pascual, humanist doctor