One year later, the high-fat, low-carb group had lost three times as much weight — 12 pounds compared with four — and that weight loss came from body fat, while the low-fat group lost muscle. Even more persuasive were the results of blood tests meant to measure the risk of heart disease and diabetes. The high-fat group, despite eating nearly twice as much saturated fat, still saw greater improvements in LDL cholesterol, HDL cholesterol, and triglycerides.
This was enough to improve their scores on the Framingham Risk Calculator, a tool for predicting 10-year risk of heart attack. The low-fat group, by contrast, saw no improvement on their Framingham scores. "I think the explanation lies in how the low-fat dieters filled the hole left by fat — they just ate more carbs," Bazanno says.