Low- and middle-income countries (LMICs) face a rapid change in the nutrition transition toward increases in noncommunicable diseases. Underlying this transition are shifts in the agricultural system and the subsequent growth of the modern retail and food service sectors across all regions and countries, a change in technology affecting physical activity and inactivity, mass media access, urbanization, and penetration of modern food systems into all societies. The resulting major shifts in diet are toward increased refined carbohydrates, added sweeteners, edible oils, and animal-source foods and reduced legumes, other vegetables, and fruits. Most countries are seeing increases in body mass index (BMI), overweight, and waist circumference (WC), and an increased WC-BMI ratio appears to be emerging in many regions. The implications of these rapidly changing diets and body compositions include the prevalence and severity of diabetes in LMICs.