Many modern weight loss diets are based on the principle of increased protein intake. These include the ketogenic diet and the Dukan diet. The creator of the latter, French doctor Pierre Dukan, gives paradoxical assurances that on his diet, one can eat as much as they want, and according to reviews from those losing weight, it seems to yield phenomenal results…
Let’s figure out how beneficial protein really is for weight loss (for girls, women, and men), in what form it is best consumed (sports protein or natural protein-rich foods), and in what quantity.
Main thoughts:
The Benefits of Protein for Weight Loss: Scientific Facts
To lose weight, it is very important to restrict the overall calorie intake of the diet throughout the day (to consume fewer calories than expended), rather than juggling magical products, fat burners, supplements, and all sorts of nonsense that only lighten your wallet.
Protein indeed plays a very important role in weight loss, as in the context of a calorie-restricted diet
- it helps preserve muscle mass from catabolism (destruction) in conditions of energy deficit;
- it requires more effort (energy) from the body for its digestion.
Let’s present some scientific facts.
Experiment: The Benefits of Protein for Weight Loss in Conditions of Caloric Restriction
In a landmark experiment involving men and women suffering from obesity over the course of 1 year, researchers reduced the caloric intake of their diet by 500 kcal, placing one group on a high-protein diet (1.6 g of protein per kg of body weight) and the other on a low-protein diet (0.8 g/kg).
The result: in both groups, both men and women lost weight approximately equally by 9.9-11.2%. This is roughly equivalent to a person weighing 100 kg losing 10 kg of fat! Not too bad.
But. Does this example not prove that protein has no advantages for weight loss: the result was the same for both the high-protein and low-protein diets?
Measurements of body fat mass showed that the high-protein diet group experienced a greater reduction in fat mass (~14.3%) compared to the low-protein diet group (~9.3%), while the caloric intake was the same 1.
The conclusion is obvious: the low-protein diet group lost more muscle mass over the course of the experiment.
Weight loss due to restricted caloric intake inevitably leads to muscle mass loss, and with reduced protein intake, muscle mass is lost even faster, despite the caloric intake remaining the same 2.
A high-protein diet is particularly beneficial for weight loss in older adults (both women and men), who experience active muscle mass reduction due to aging processes.
When losing weight on a calorie-restricted diet, if the diet is low in protein, more muscle mass is lost
Experiment: The Benefits of Sports Protein for Women’s Weight Loss
This study involved older women with excess weight at around 65 years of age.
They were placed on a calorie-restricted diet – 1,400 kcal (15%, 65%, 30% of energy from proteins, carbohydrates, and fats), with some of them taking an additional 50 g of whey protein daily twice a day, while another group consumed the same amount (50 g) of carbohydrates. The total caloric intake was the same for both groups.
After 6 months, the women on the protein diet lost an average of 8%, while the carbohydrate group lost 4%. Moreover, the protein diet group showed less muscle mass loss 3.
Consuming sports protein during weight loss helps preserve muscle mass and slightly increases the degree of weight loss
Experiment: The Effectiveness of Different Amounts of Protein for Weight Loss
In another experiment, scientists compared the effectiveness of a diet with a protein share of 15% (relative to total caloric intake) and 30%.
Result: the overall weight loss in the first group on a low-protein diet averaged ~11 kg, 37% of which was muscle mass, while in the group on a high-protein diet, the total weight loss was slightly lower (~8 kg), but the loss of muscle mass was 2 times (!) less (~17.3%) 4.
A protein diet with a protein share of 30% (of total caloric intake) allows for significantly more muscle mass to be preserved compared to 15%
This and many other 5,6,7 studies unequivocally confirm that high-protein diets are beneficial for weight loss for both men and women, despite the fact that, by nature, men find it easier to lose weight.
At the same time, it does not particularly matter which protein is used.
Even a slight tendency towards higher protein intake during weight loss is associated with more favorable changes in body composition for both women and men 8.
For example, take a look at an interesting piece about what simple consumption of eggs for breakfast can do for your body.
Protein consumption has clear advantages for weight loss for girls, men, and women and helps maintain muscle mass on a low-calorie diet
Although most scientific experiments involve women of Balzac age and there are practically no studies on the effectiveness of protein for weight loss in young women, you can be sure that for this most concerned part of humanity regarding their problem areas, a protein diet works as well.
The secret lies in the properties of protein that distinguish it from carbohydrates and fats:
- it provides greater satiety (you feel less hungry as it is digested more slowly);
- protein promotes muscle mass preservation when you restrict calories;
- it has a thermogenic effect (significantly more calories are expended on its own digestion).
Which protein is best for weight loss?
The studies described above mainly confirm the simple fact of the benefits of protein itself for weight loss and muscle mass preservation. They do not specify which particular protein is best for weight loss.
However, when considering other studies aimed at determining the effectiveness of different types of proteins, it is clear that those with a higher proportion of essential amino acids are more effective for weight loss 11. This is also important for bone health 12.
The sources of such proteins are usually animal products: meat, fish, eggs, and dairy products, as well as popular types of sports nutrition such as whey protein and casein, which are derived from milk (milk protein consists of 80% casein and 20% whey).
A few words about sports proteins. They have some advantages for weight loss over natural protein-rich foods, as well as disadvantages:
- they contain limited amounts of fats and carbohydrates;
- they are more expensive;
- some forms of these proteins do not have a thermogenic effect, as their protein molecules are already partially broken down for quick digestion (hydrolysates, for example);
- it is better to choose “slow” proteins (casein, milk protein) from sports proteins, as “fast” proteins enter the bloodstream instantly and can partially convert into glucose, which is easily stored as fat. See Types of protein in sports nutrition.
In terms of price and quality, it is optimal to consume natural low-fat proteins (low-fat dairy products, lean meat, and fish).
Natural low-fat protein-rich foods are the optimal source of protein for weight loss. Sports proteins do not have significant advantages.
We recommend: What NOT to eat and what to EAT to lose weight?
How much protein do you need to eat to lose weight?
Scientists say that a high-protein diet (~34% of total caloric intake from protein) is significantly more effective in reducing body fat levels and is more beneficial for both health and weight loss 6,7.
Look at the results of the following experiment.
Experiment: The benefits of a diet with a protein dose of 2.2 g/kg body weight for health and weight loss compared to 1.1 g/kg
In this 12-week study, scientists compared the effects of a low-protein (1.1 g/kg) and a high-protein diet (2.2 g/kg).
Result: participants in the high-protein diet group not only lost more weight, but their blood also showed a decrease in “bad” low-density cholesterol, which was not observed in participants in the low-protein diet group 5.
For weight loss, it is recommended that about 30% of calories in the diet come from protein (or approximately 1.5-2 g of protein per kilogram of body weight)
A logical question may arise: is such an amount of protein harmful?
The question of the harm of protein has been well studied. In general, scientific research indicates its safety for the health of the kidneys, liver, and bones in healthy individuals, both in the short term and long term.
Postscript
Protein has undeniable advantages for weight loss compared to other nutrients (carbohydrates and fats).
Many popular weight loss diets are built around the use of protein as a main ingredient, particularly the Dukan diet and the ketogenic diet.
From a weight loss perspective, sports proteins do not have significant advantages over natural protein products. However, there are disadvantages.
It is optimal for health and weight loss to ensure that approximately 30% of calories come from protein.
