Given the same context and diet, some individuals are more likely than others to gain weight. Genes (and therefore heredity), but also intestinal flora (also known as microbiota), could partly explain these differences. However, they cannot be held solely responsible. People who don't gain weight often have an active lifestyle and a balanced diet.

For further information, we recommend that you consult :

- The MangerBouger.fr website
- The Santé Publique France website, and its nutrition and physical activity section
- The ANSES website (Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail), and its section on food and human nutrition.
- The French Nutrition Society website
- The report of the PNNS, Programme Nationale de Nutrition et Santé (2018-2023), which defines all nutritional recommendations.