Obesity is considered a chronic disease. It is present in all industrialized countries and constitutes a societal problem because it has adverse consequences on the health of the population.

Today, in several European countries, it is estimated that at least one third of the population is overweight. The experts calculated that obesity consumes 3 to 8% of medical expenses in these countries, is the equivalent of programs against cancer or AIDS. Obesity is indeed a phenomenon that is in full development. It remains to know the causes that are numerous and often multi-factorial because the accumulation of several factors leads to obesity.


70% of obese have at least one parent in the same situation. Genetic abnormalities result in reduced expenditure on rest and physical exertion, decreased energy expenditure after meals and a particular distribution of adipose tissue or fat mass. However, it is considered that they are not sufficient to explain the onset of obesity except for Prader-Willi disease (very rare).


Diet plays an important role in the process of weight gain or weight loss, in effect a food imbalance influences all the health of the individual, otherwise, the main causes of diet imbalance leading to obesity are:

 ➡ A diet too high in calories (high caloric density): for example, excessive consumption of fat (oil, butter), sweetened or alcoholic beverages.

➡ The food intake outside meals: nothing, snacks, snacks, and more generally food intake outside meals bring a lot of calories.

➡ Food intake triggered by annoyances, stress, emotions.

➡ Diets too severe: the more severe diets, the greater the risk of gaining weight. When you no longer support the diet and you “crack”, you quickly consume a lot of calories in no time.

➡ Meals and snacks in front of the TV.

➡ The loss of dietary rhythms: the suppression of breakfast or lunch promotes weight gain.

 💡 NB: Caloric density is the amount of calories contained in 100g of a food


In case of great distress or stress, we observed a compensation by the food, in particular by foods comforting very caloric.


the absence of daily physical exercise and excessive physical inactivity (fixation in front of the screens in particular) lead to a reduction in energy expenditure and an unfavorable imbalance in relation to food intake.


Various studies have shown an epidemiological association between short sleep duration and a high body mass index linked to obesity. When the duration of sleep is less than 5 hours per night, the risk of obesity increases by 60%. In fact, every one hour increase in sleep duration is accompanied by a 9% reduction in the risk of obesity. Moreover, a sleep of less than 6h multiplies by 4 the risk of obesity compared to a sleep of more than 7h. This impact is so far greater than that of food intake or lack of physical activity.


There is no drug that causes weight gain. However, certain medical treatments modify satiety and must be accompanied by a healthy lifestyle so as not to cause overweight. This is the case of corticosteroids, birth control pills, menopause treatments.


Some reasons that can promote weight gain:

  1. Unbalanced diet;
  2. Lack of physical activity and sports;
  3. Smoking cessation;
  4. Alcohol consumption;
  5. Certain drugs;
  6. The menopausal period;
  7. Periods of psychological or social vulnerability (professional or personal difficulties);
  8. Decreased sleep time.

  1. The overweight concerns 1.4 billion people aged 20 years and over in the world (WHO global estimates). By 2030, the number of overweight people is expected to reach 3.3 billion.
  2. Overweight and obesity are the fifth leading risk factor for death worldwide, with at least 2.8 million deaths each year.

Source: World Health Organization (WHO) – “Obesity and overweight” – FS N ° 311