The National Institutes of Health in the US financed a yearlong trial on low-carb- versus low-fat-focused eating. In it, 150 men and women of different races followed either a low-fat or a low-carb diet. Neither group limited their kilojoule intake, nor changed their levels of physical activity. The results were surprising:
1. The low-carb group lost about 3,6kg more on average than those in the low-fat group.
2. The low-carb group lost more body fat than the low-fat group, and had improvements in lean-muscle mass. While the low-fat group did lose weight, they appeared to lose more muscle than fat.
3. The low-carb group’s markers of inflammation and triglycerides (a type of fat that circulates in the blood) dropped significantly. Their HDL (good cholesterol) rose more sharply than it did for people in the low-fat group.
4. Blood pressure, total cholesterol and LDL (bad cholesterol) stayed about the same for people in each group.
5. The low-carb group lowered their Framingham risk scores, which calculate the likelihood of a heart attack within the next 10 years. On average, the low-fat group had no improvement in their scores.