Purpose of review: The aim of this article is to evaluate food properties able to influence specific physiological targets that may be helpful for the prevention and management of overweight and diabetes.
Recent findings: Observational and intervention studies have clearly shown that type 2 diabetes can be prevented by lifestyle measures, including reduced energy intake to induce a modest but sustained weight reduction, together with changes in diet composition.
Summary: Foods can be regarded as functional if proven to affect beneficially one or more target functions in the body, beyond adequate nutritional effects, in a way relevant to improved state of health and well-being, reduction of risk of diseases, or both. Functional foods might have a particularly high impact for prevention or treatment of overweight and diabetes for which, more than in many other fields, the link between nutrition, biological responses and diseases is clearly established. Functional foods for obesity should be able to influence the energy balance equation regulated by the control of energy intake or of energy dissipated as heat (thermogenesis). For prevention of type 2 diabetes, several unmodified foods with functional properties have already been identified (low saturated fat products, vegetables, fruit, wholegrain foods, low glycemic index starchy foods). Overall, the available evidence on functional foods so far identified in this field is incomplete: the major gap is the lack of diet-based intervention trials of sufficient duration to be relevant for the natural history of diseases like overweight and diabetes.