The prevalence of obesity and dyslipidemia and the mean frequency of intake of selected dietary factors were studied in 545 participants aged 46-58 y and living in three areas in Tanzania. The prevalence of obesity (body mass index of > or = 30 kg/m2) was 22.5% among women and 5.4% among men, p < 0.001. Higher rates of obesity were observed in both men and women in an urban (U) area of Dar. The prevalence of dyslipidemia [(TC-HDL-C)/HDL-C > 5] among men was higher in a pastoralists (P) population of the Maasai in Monduli (22.6%) than in Dar (9.6%) and rural (R) Handeni (7.3%, p < 0.05). The mean resting energy expenditure (REE) was higher in subjects from the rural and pastoralists populations than in urban dwellers (0.024 kcal/min/kg, p < 0.001). The three areas showed different dietary patterns with subjects from the urban area consuming coconut milk (4 d/wk, p < 0.001) and meat (2.5 d/wk, p < 0.05), more often than the rural population of Handeni which had the highest consumption of green vegetables (4.2 d/wk, p < 0.001). Participants from Monduli had the highest consumption of milk per day (1,219 mL/d, p < 0.001). A simple correlation analysis showed that body mass index (BMI) correlated positively with the frequency of intake of coconut milk, fish and meat, and negatively with REE and milk consumption. Total cholesterol (TC) was negatively correlated with the frequency of intake of green vegetables, fish and the REE, and correlated positively with meat consumption and BMI in both genders. Independent of other factors, important contributors to obesity and dyslipidemia in this population were dietary factors such as meat (p < 0.001) and fish (p < 0.05), and a lower REE (p < 0.05). These findings suggest that unhealthy diet and lower energy expenditure are important contributors to obesity and dyslipidemia in Tanzania.