A low-carb low-protein diet is a weight-loss diet in which a relatively small proportion of total calories come from carbohydrates or protein. It is high in fat, with unsaturated fat making up the bulk of calories consumed. Compared to typical nutrition recommendations, which often emphasize carbohydrates, a low-carb low-protein diet calls for fewer calories from carbohydrates and more from fat. Proponents of this diet report that it leads to a greater feeling of satiety and influences the hormone leptin, which has been linked to appetite control. This allows dieters to feel satisfied on a low-calorie plan, though critics argue a limited number of foods are allowed on this kind of diet, and that like any low-carbohydrate plan, there may be health risks involved.
Quietly increasing in popularity, the low-carb low-protein diet is being promoted by advocates of other low-carb diets like the South Beach Diet® and Atkins™ who believe reducing carbohydrate levels and increasing consumption of healthy fats will lead to more successful weight loss. Like these diets, the low-carb low-protein model pushes the inclusion of fats from foods like olive oil, avocado, walnuts, and fish while reducing or often eliminating sugars and other refined and complex grains, dairy, and fruit. The idea behind this model is that dietary fat helps to create a feeling of fullness, especially when paired with fiber-dense vegetables that add bulk to food.
The low-carb low-protein diet is said to manage levels of the hormone leptin, a protein that tells the brain when the person is full. Like insulin to diabetics, some overweight or obese individuals have a resistance to this hormone. Proponents of the diet claim that eating this way helps to reactivate leptin and subsequently discourage overeating.
While the low-carb low-protein diet makes room for many almost universally recommended foods like green vegetables, foods rich in unsaturated fats, and lean meats, critics observe that it cuts out many foods that are also widely recommended for their nutritional content. These include fruit, whole grains, several types of vegetables and starches, beans, and low-fat dairy. While they tend to agree with promoting the consumption of healthy fat, a nutrient that until recently had been vilified by many diet programs, they are concerned with the elimination of potentially healthy foods, particularly the reduction in carbohydrates.
Typical dietary recommendations state that of the three macronutrients — carbohydrates, fat, and protein — 45-65 percent of total calories should come from carbohydrates, 25-30 percent should come from fat, and 10-15 percent should come from protein. Carbohydrates are the body’s most immediate and basic source of energy and are crucial to certain populations like athletes. Too great a reduction of carbohydrates as well as overall calorie intake can negatively impact brain function, energy levels, kidney function, and the ability to generate or maintain muscle mass. In addition, critics of the low-carb low-protein diet claim that nutrient deficiency can result from eliminating many complex carbs like whole grains and other starches.