Fats in the Diet
The limitations of reduction in fat as a general strategy are evident in the pattern of consumption during the obesity epidemic where almost all the increase in calories was due to the increase in carbohydrate consumption. The massive Women’s Health Initiative showed that reducing dietary fat did not improve the incidence of obesity, cardiovascular disease or diabetes.
And it’s not just the type of fat. Whereas replacing saturated fat with unsaturated fat may be beneficial, replacing any fat with carbohydrate is generally deleterious for cardiovascular disease, diabetes and weight gain. How is this possible? The effect of dietary fat is controlled by carbohydrate, directly or through stimulation of insulin which is an anabolic hormone and tends to bias metabolism towards fat storage rather than oxidation. You are not what you eat. You are what you do with what you eat. For this reason, carbohydrate restriction will generally trump the effects of any kind of fat.
Much careful research shows that carbohydrate-restricted diets, even when they increase fat intake are generally beneficial for cardiovascular disease and diabetes, and no diet has ever been shown to be more effective for weight loss. Conversely, there are now numerous popular books and scientific studies pointing out how political considerations gave rise to the low fat idea in the face of much contradictory evidence.