Individualized weight management: what can be learned from nutrigenomics and nutrigenetics?
The rise in the prevalence of obesity observed over the past decades is taken by many as an indication of the predominance of environmental factors (the so-called obesogenic environment) over genetic factors in explaining why obesity has reached epidemic proportions. While a changing environment favoring increased food intake and decreased physical activity levels has clearly contributed to shifting the distribution of body mass index (BMI) at the population level, not everyone is becoming overweight or obese. This suggests that there are genetic factors interacting with environmental factors to predispose some individuals to obesity. This gene-environment interaction is not only important in determining an individual's susceptibility to obesity but can also influence the outcome of weight-loss programs and weight-management strategies in overweight and obese subjects. This chapter reviews the role of gene-nutrient interactions in the context of weight management. The first section reviews the application of transcriptomics in human nutrition intervention studies on the molecular impact of caloric restriction and macronutrient composition. The second section reviews the effects of various obesity candidate gene polymorphisms on the response of body weight or weight-related phenotypes to weight-loss programs which include nutritional interventions.