There have been many diets and weight loss plans that have come and gone over the years. Low-carbohydrate, high-protein diets were popular decades ago. And today are making a comeback.These diets do promote weight loss. Low-carbohydrate, high- protein diets are more effective. Than low-fat, low-cholesterol, low-calorie diets. Also your cholesterol levels often improve more on a low-carb diet.A low-carb diet plan structures your eating choices around the selection of lean protein sources. Focusin.