Obesity is a complex disease rooted in both physical and behavioural factors.
Genetic inheritance plays a role in weight gain
There are many scientific studies that have demonstrated a clear statistical correlation between genetic inheritance and obesity.
Increased risk for children of obese people
Children born to “normal” or thin parents have less than a one in ten chances of developing the disease. If one of the parents is obese, the risk increases to four chances out of ten and it reaches eight chances out of ten if both parents are obese. Overall, it is currently estimated that the role of heredity in obesity is around 40 to 50%.
Gene therapies are being studied to cure some cases linked to a single genetic mutation. However, it is still far too early to fully understand and, even more so, be able to treat all the genetic factors associated with the most common cases.
A single gene can alter metabolism and cause severe obesity
A few isolated cases are caused by a single defective gene altering the metabolism from birth and almost certainly leading to severe obesity. However, scientists have identified tens of genes that can induce a certain predisposition to the disease. These genetic particularities can combine and be aggravated by other lifestyle factors.
A poor lifestyle, a major factor in weight gain
Before resorting to medication or bariatric surgery, it is necessary to act on three fronts: nutrition, exercise and mental health. To change lifestyles, it’s important that changes be gradual and lasting to be beneficial.
Psychological trauma can be the cause of eating disorders
It is common for people suffering from obesity to have had a childhood or adolescence marked by socio-emotional deficiencies and psychic traumas leading, a few years later, to eating disorders. These cannot be permanently eliminated without addressing their psychological causes.
Pathologies such as metabolic or hormonal disorders can slow down weight loss.
Finally, as we have previously seen, severe obesity is often linked to genetic factors, but also to complex pathologies such as metabolic or hormonal disorders. The combination of all these factors makes losing weight and maintaining it extremely difficult for people struggling with the acute stages of this disease.
Sources :
Understanding genetics of obesity will require larger studies, effect sizes , Healio, mars 2018.
Principaux repères sur l’obésité et le surpoids, Organisation mondiale de la santé, Mars 2024.
Obésité : Une maladie du cerveau ?