Protein for weight loss – how it supports weight loss in athletes

In 1838, nitrogenous compounds present in animal tissues were described, and the name "protein" was subsequently proposed for them, derived from the Greek word meaning "of primary importance". This was a significant moment in the history of nutritional science, as protein began to be regarded as the body’s primary building block, rather than merely one of the components of food. Nowadays, its importance is particularly significant in sport, especially when the aim is not merely to lose weight, but also to maintain fitness levels.

1. Characteristics of cutting
2. Protein for weight loss
3. Protein in the diet
4. European Food Safety Authority

Characteristics of cutting

Cutting is a phase of nutrition and training aimed at reducing body weight, primarily body fat, whilst preserving exercise capacity and muscle mass as much as possible. Among beginners, it is often simply equated with "losing weight".

In physique sports, cutting usually involves improving appearance and body proportions, whereas in weight-class sports it may be linked to the need to achieve a specific starting weight. For those who train (both recreationally and competitively), it is not only the rate of weight loss that matters, but also what proportion of that loss comes from body fat and what proportion from lean body mass.

Of key importance for weight loss is an energy deficit, i.e. a situation in which the body receives fewer energy sources in the diet than its total daily expenditure. However, the deficit should not be too aggressive, as this can lead to increased fatigue, a decline in training quality, a reduction in spontaneous activity, a greater feeling of hunger and more difficult recovery.

"Protein is the most frequently discussed macronutrient in sports nutrition and among those on a diet. It is therefore no surprise that there are so many different types of protein supplements available. Even if whey protein seems to offer more benefits than egg white powder, note that the latter is also a source of high-quality essential amino acids that the body needs." Łukasz Domeracki – Dietitian

Protein for weight loss

Protein is important during weight loss mainly because it contributes to muscle mass growth and helps maintain muscle mass, whilst the weight-loss process itself increases the risk of losing lean body mass, especially when the diet is poorly planned, the calorie deficit is large, and the training volume is either too low or too high. Advanced athletes often consume higher amounts of protein than during a weight maintenance phase, as weight loss increases the importance of satiety, recovery and the supply of amino acids to the muscles.

Protein also has a higher thermic effect than fats and carbohydrates, meaning that its digestion, absorption and metabolism involve a greater energy cost for the body. However, a high protein intake does not replace energy, sleep or a training plan; therefore, with a very low calorie intake, even a well-chosen amount of protein may not be sufficient to maintain full recovery quality and sporting performance.

Estimated protein content in some sources

Protein in the diet

Sources of protein in the diet can be divided into animal products, plant-based foods and protein supplements. Classic animal sources include lean meat, fish, eggs and quark, and their advantage lies in their complete profile of essential amino acids. An athlete’s diet often includes chicken or turkey breast, lean beef, cod, pollock, tuna, salmon, eggs, semi-skimmed quark, cottage cheese, skyr and fermented dairy products such as kefir.

Plant-based products such as tofu, tempeh, soya, lentils, chickpeas, beans, peas, seitan, quinoa, seeds and nuts can also provide protein, but some of them contain more carbohydrates or fat, which can increase the calorie content of a given meal and diet. Among supplements, the most commonly used are whey protein concentrate, whey protein isolate, micellar casein and plant proteins, such as soya, pea, rice or blends of several plant fractions.

European Food Safety Authority

The European Food Safety Authority (EFSA) has not established separate protein intake guidelines for athletes or for people trying to lose weight. The reference value for healthy adults is 0.83 g of protein per kg of body weight per day, but in sport, particularly during an energy deficit and resistance training, higher amounts are usually consumed. No upper tolerable level of protein intake has been established; however, it has been indicated that in adults, intake of up to approximately twice the reference value, i.e. around 1.66 g/kg body weight/day, can be considered safe at a population level.

Sources:

• Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. J Int Soc Sports Nutr. 2014;11:20. Published 2014 May 12. doi:10.1186/1550-2783-11-20
• Helms ER, Zinn C, Rowlands DS, Brown SR. A systematic review of dietary protein during caloric restriction in resistance trained lean athletes: a case for higher intakes. Int J Sport Nutr Exerc Metab. 2014;24(2):127-138. doi:10.1123/ijsnem.2013-0054
• Halton TL, Hu FB. The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review. J Am Coll Nutr. 2004;23(5):373-385. doi:10.1080/07315724.2004.10719381