2.c. Abdominal Fat
Rationale: Four RCTs testing the effects of weight loss on blood lipids also included measures of abdominal fat, as measured by waist circumference (365, 373, 375, 399). In each study, waist circumference was reduced along with weight, and blood lipids were improved. These studies were not designed to test whether reductions in abdominal fat reduce blood lipids independent of weight loss. However, evidence exists from epidemiologic observational studies that abdominal fat is related to an adverse lipid profile, including higher levels of total cholesterol, LDL-cholesterol, and triglycerides, and lower levels of HDL-cholesterol (409, 410).