Why are proteins effective for losing weight?

Satisfying, difficult to store by the body, useful for maintaining muscle mass: proteins are real allies for weight loss. Slimming diets often put them in the spotlight, sometimes even banishing other nutrients from their menus, in order to achieve ever faster weight loss. Be careful, however, as excess protein is harmful to your health and too rapid weight loss is never sustainable. Raphaël Gruman, dietitian nutritionist in Paris, gives us his advice for losing weight intelligently with proteins.

With nearly 6 in 10 French people saying they have pounds to lose, weight is a major concern. To achieve this, slimming diets are numerous and varied, so much so that it is easy to get lost. Those who put protein in the spotlight have the upper hand, especially the strict high-protein diet or the ketogenic diet. Why is protein effective for initiating weight loss? How to intelligently integrate them into a slimming diet? What about high-protein food supplements? Is using Whey and other protein powders effective for losing weight? The answers from Raphaël Gruman, dietitian nutritionist in Paris.

Protein: what is it?

The foods we eat every day contain 3 nutrients, which give them their caloric and nutritional value. All of them are essential to the good health of our body.

Carbohydratesbetter known as “sugar”,: these carbohydrates can be complex (bread, starchy foods) or simple (fruits, sweet products);
Lipids or fats : butter, oil, cream, mayonnaise… Lipids or fats can also be “hidden” in fatty foods, such as cheese, fatty meats, cold meats, tarama, etc.
The proteins : which can be of animal origin in meat, fish or eggs, or of plant origin in cereals, legumes, soy, etc.

These foods are essential for general metabolism. Our metabolism will allow the digestion of food, its breakdown into nutrients, the assimilation of nutrients, and the production and storage of energy.

Why is protein effective for weight loss?

Proteins and carbohydrates provide 4 calories per gram, and lipids provide 9, more than double. But although carbohydrates and proteins have an equivalent caloric intake, they do not have the same effect on weight! “Protein assimilation is very complex for our body. It increases thermogenesis – namely the production of heat by the body – and therefore generates a greater caloric expenditure than when we eat carbohydrates, which are easily assimilated. explains the nutritionist.

This is called the thermal effect of food, or TEF (Thermic Effect of Food). It is difficult to say precisely how much the assimilation of a gram of protein causes in terms of caloric expenditure, since it varies greatly depending on the person and their basic metabolism. “But overall, to assimilate 1 g of protein, we spend many more calories than to burn 1 g of carbohydrates or fat. This explains why you can eat very large quantities of pure protein and still lose weight. underlines Raphaël Gruman.

In addition to the low assimilation of proteins by the body, they are valuable as part of a slimming diet because they are the main constituent of muscle fibers. They thus help maintain muscle mass, which is often reduced during weight loss. “It is essential to maintain your muscles when you want to lose or stabilize your weight, because it consumes the most calories. For equal height and weight, more muscular people burn more calories than others, even when resting!” recalls the specialist.

What are the best proteins for losing weight?

If proteins are interesting in the context of weight loss, they are not all equally effective. “Foods rich in animal proteins are preferred because they are generally devoid of carbohydrates, unlike foods rich in plant proteins such as legumes, quinoa or cereals which contain a lot of them.” summarizes Raphaël Gruman.

The leanest are also the least caloric, like poultry, white ham, lean parts of beef, white fish or even eggs. “Certain dairy products are also very interesting, in particular low-fat cottage cheese and even more so Skyr, very rich in protein and devoid of lipids. For vegetarians, protein foods that contain no or few carbohydrates are: tofu, seitan, tempeh or even textured soy proteins..

Whey, casein, isolate… What about protein-based food supplements?

In the food supplement section, there are many high-protein products, such as bars, drinks or sachets of powder to dilute. Is this source of protein useful for losing weight? “I tend to advise against these products, which are in practice no more interesting than lean meat, fish or skyr, and which provide little taste satisfaction. In addition, they are less filling” underlines the dietician. Whey, casein, protein shakes and isolates in the form of powder, bar or supplements are intended more for athletes looking to gain muscle mass, and not for following a long-term diet.

What are the disadvantages of a strict high protein diet

Protein being the most difficult nutrient for the body to assimilate and store, strict high-protein diets allow you to lose weight quickly and without feeling hungry. “However, these are not diets that I recommend, because they have many disadvantages” insists Raphaël Gruman. First of all, these are very unbalanced diets, which should therefore not be followed in the long term at the risk of generating significant deficiencies in vitamins and minerals of which meat, fish and vegetables are almost devoid. eggs.”The high-protein diet is also very low in fiber, and is often the cause of digestive disorders and slowed transit.” adds the dietitian. Excess proteins are also bad for the kidneys because they can harm kidney function.

In addition to the health harms linked to excess protein, the second disadvantage of high-protein diets is the rebound effect observed when stopping the diet. “Although these diets are very effective in losing weight, they are extremely difficult – if not impossible – to stabilize!” alerts Raphaël Gruman. When we reintroduce carbohydrates and lipids, the body reacts to this deprivation by immediately storing them in the form of body fat, resulting in a significant weight gain.

The ketogenic diet, a better option?

By combining lipids with proteins, the ketogenic diet helps limit deficiencies and above all facilitates stabilization once a healthy weight is reached. This is why we prefer a ketogenic diet which allows lipids in addition to proteins, and thus significantly limits the risk of deficiencies. “The ketogenic diet allows the addition of vegetable oils, fatty fish and oilseeds, rich in essential fatty acids and fat-soluble vitamins” indicates the dietitian nutritionist.

The only carbohydrates allowed are those from green vegetables and low-sweet fruits, such as red berries (strawberries, blackberries, raspberries, etc.), melon or watermelon. “Carbohydrates should not exceed 10 to 15% of total energy intake” recalls Raphaël Gruman.