Nutrition and chronic disease: lessons from the developing and developed world.

Many features of human susceptibility to chronic noncommunicable diseases can be mapped onto the framework of the match/mismatch hypothesis. From an evolutionary perspective, it is highly likely that the human genome has been under selective pressure to survive and reproduce against a background of seasonal food shortages and frequent episodic famines, leading to the attractive, but unproven, concept of 'a thrifty genotype made deleterious by famine'. From an ontogeny perspective, it has been clearly demonstrated that fetal undernutrition leads to a thrifty phenotype that enhances metabolic risk if the individual is later exposed to an energy-abundant environment. Data from developing and rapidly emerging countries permit insights into both of these pathways. Many populations are rapidly emerging from conditions broadly representative of human history over the past 600 or so generations (i.e. since the dawn of agriculture) and are transitioning within very few generations to a state of dietary abundance and low physical activity. And within this framework, many individuals make an even more rapid personal transition from the womb of a malnourished mother to a state of affluence. These journeys provide exceptional opportunities to interrogate thrifty genotype/phenotype theories, but such prospects are frequently impaired by a lack of robust data.