Pacific people (especially Micronesian and Polynesian) have some of the highest rates of obesity and diabetes in the world that largely developed since the introduction of western culture and diet. Recent studies suggest that much of the risk relates to the excessive intake of sugar (sucrose) and carbohydrates, leading to a type of fat storage syndrome (metabolic syndrome). Here we discuss some of the environmental. genetic and epigenetic reasons why this group might be especially prone to developing obesity and diabetes compared to other ethnic groups. Indirect evidence suggests that the higher endogenous uric acid levels in the Polynesian-Micronesian population may represent a predisposing factor for the development of obesity and diabetes in the context of Western diets and lifestyles. Pacific people may be an ideal group to study the role of "thrifty genes" in the pathogenesis of the current obesity epidemic.