The worldwide overweight and obesity epidemic, and weight-related health complications such as diabetes and cardiovascular disease, have become critical healthcare issues in both developed and developing economies.
Much of the research focus to date has been on strategies to help people lose weight. However, very little is known about why certain people are resistant to weight gain in the first place. Understanding the biological mechanisms that underlie this resistance to weight gain can help in providing solutions that work on long-term weight and health maintenance.
Indeed, novel insights on metabolic differences in humans might come from studying very lean people, a state called Constitutional Thinness (CT). CT individuals eat normally but exhibit a natural resistance to weight gain.
Nestlé Research scientists, along with clinical researchers from the Clinical Hospital at the University of St-Etienne, in France, identified the molecular aspects underlying the low body weight and fat of CT individuals.
The results of the study published in the American Journal of Clinical Nutrition, show that CT individuals have distinct differences in their fat tissue. Despite the fact that their fat cells are smaller, they contain more mitochondria, which produce energy in cells. The increased mitochondrial activity results in a higher fat burning rate and, surprisingly, also to higher fat synthesis. These mechanisms lead to an increase of energy expenditure, and thus to resistance to weight gain.
“Understanding the natural reasons why some people are resistant to weight gain could provide new biological targets for weight management solutions and could ultimately allow more targeted nutritional approaches for obese people helping them in long-term weight maintenance,” said Dr Nele Gheldof, from Nestlé Research.