Obese people are solely responsible for their condition
“Obesity is not a personal choice,” says Dr.D Mélanie Henderson, pediatric endocrinologist at the Sainte-Justine University Hospital Center (CHU). Genetics matters a lot. “Its impact in the development of obesity varies between 20 and 80%, she indicates. Several genes determine weight. »
Two people with the same lifestyle but not the same genetic background can therefore have very different body mass indexes (BMI). “We know that when a patient has many genes predisposing to obesity, he will often have a higher BMI than a patient who has exactly the same lifestyle habits, but who has a lower predisposition,” says the DD Marie-Philippe Morin, specialist in bariatric surgery at the University Institute of Cardiology and Pneumology of Quebec.
But obesity is not just about genetics. “It’s a multifactorial health problem,” underlines the DD Henderson. “Environmental elements” contribute to obesity: “the sedentary lifestyle of our society, the reduction in physical activity and active transportation, changes in diet, the accessibility of processed food, all the phenomenon of Super Size Me [Malbouffe à l’américaine] », she lists.
The obese just have to eat less and move more. They will lose weight.
The claim is simplistic, and the reality much more complex, experts say. In its clinical practice guidelines, Obesity Canada indicates that the weight loss achieved through lifestyle changes “usually varies from 3% to 5%” in obese people, but “can significantly improve the comorbidities” that are linked to this chronic disease.
“Physical activity and diet have a lot of benefits on many things: on cardiovascular risk, on cardiorespiratory capacity, on abdominal circumference, on blood sugar, underlines the DD Morin. On the other hand, the modification of lifestyle habits alone leads to a generally modest weight loss. Many patients regain the lost pounds later.
According to endocrinologist Rémi Rabasa-Lhoret, around 80% of obese people who have lost weight by eating better and moving more regain it partially or completely. A similar phenomenon occurs in patients who stop the drug Ozempic, a treatment for type 2 diabetes that causes weight loss, specifies the vice-president, clinic and clinical research at the Montreal Clinical Research Institute. “Even with bariatric surgery, in the long term, there is a tendency to regain weight,” he continues. Much less than with the other options, but still. »
And why ? The DD Morin explains that hunger hormones increase after weight loss and satiety hormones decrease. “There is also a slowdown in basal metabolism. It is an adaptation mechanism, a defense mechanism of the body, in reaction to weight loss. It was a good mechanism when we were in a famine situation a century ago. But it is certain that, in an obesogenic environment, weight gain is easier. »
In context, weight loss doesn’t have to always be the goal, says Dr Rabasa-Lhoret. “The goal is for people to feel better, to have fewer illnesses and less need for medication to treat them,” he says. They can achieve this and improve their health by changing their lifestyle habits.
Obesity is defined as a BMI of 30 or more.
“Obesity is not a BMI, reports the DD Morin. There must be consequences in terms of physical, psychological, functional and metabolic health. [pour qu’il y ait diagnostic]. If this has no impact, it is a weight that is at risk. »
According to her, BMI is a “very imperfect screening tool.” “It doesn’t take into account the distribution of fat: is it abdominal, at the hips, subcutaneous? It does not take into account muscle mass, breast volume in women, ectopic fats (in the liver, pancreas, heart, etc.), ”she explains.
Researcher Jean-Pierre Després believes that using BMI to diagnose obesity and the risks associated with it is “a completely outdated concept”. Waist size is a much more important variable than weight, he insists. Thirty years ago, he was among the first in the world to make the link between abdominal (or visceral) obesity and the risks of type 2 diabetes and cardiovascular disease.
“We realized while doing scans across the body that people who have visceral obesity have fatty livers and have their heart wrapped in fat,” explains Mr. Després, who is also scientific director of VITAM, a sustainable health research center of the CIUSSS of Capitale-Nationale, affiliated with Laval University. “Their skeletal muscles look like Kobe steak. It’s all marbled with fat. It creates a state of chronic inflammation. »
This is not the case for the fat lodged in the buttocks and thighs of women, “good fat”, according to Jean-Pierre Després. “This fat is mobilized when the woman breastfeeds,” he says. This ensured the survival of the species at a time when there were no calories available. »
Large cohort studies have since shown that “the more fat women have in their buttocks and thighs, the more protected they are against cardiovascular events and type 2 diabetes,” he reports. An advantage that gradually disappears at menopause, due to the fall in female hormones. Women’s waistlines then begin to increase.
Men and women can therefore suffer from abdominal obesity without reaching the obese BMI of 30. “We should talk about “obesity”, in the plural, rather than obesity,” he concludes.
People who have a BMI of 30 or more are in poor health
According to the Dr Rémi Rabasa-Lhoret, between 10 and 15% of people with a BMI of 30 or more are “metabolically normal”, that is to say they do not suffer from type 2 diabetes, hypertension or problems of cholesterol. “There are very good studies, especially in our large neighbors to the south, which show that overweight or obese people, if they are very physically active, will develop fewer complications, such as diabetes and cardiovascular diseases, than people of normal weight who are sedentary,” he says.
Being obese and “metabolically normal” does not mean that you will always remain so, recalls Dr. Rémi Rabasa-Lhoret. Other health problems linked to high weight can also occur, such as osteoarthritis or a mental health disorder.
According to the DD Morin, people with a high BMI who are not sick “tend to have a slightly higher cardiovascular risk than other patients who are at a healthy weight”.
