Topic 18. Gain in muscle mass
p. 445-454
Texte intégral
Questions and answers
Key points
Nutrition plays an essential role in promoting muscle mass gain through a bodybuilding training programme. In this context, several strategies should be adopted to achieve the target:
■ the energy intake must be adequate to balance daily energy expenditure;
■ the protein intake should correspond to 1.8 to 2 g.kg−1.d−1 and intake should be divided throughout the day. Above these levels, no additional benefit has been noted. Supplements can be recommended, provided they have an anti-doping label;
■ the timing of protein intake is essential, with the period surrounding the bodybuilding session being optimal. Thus, consuming proteins before and immediately after the session is recommended. In parallel, combining protein ingestion with carbohydrate intake limits protein breakdown while accelerating muscle growth.
How does nutrition play an essential role during a programme to increase muscle mass?
1During the day, muscle proteins are renewed by the slow turnover generated by the competing mechanisms of protein degradation and resynthesis. Over a given period, variations in ahtlete’s muscle mass depend on the muscle protein balance, i.e. on the difference between the amount of muscle proteins broken down (through proteolysis) and the amount of synthesis. This balance fluctuates significantly throughout the day, alternating between phases when the amount of proteins synthesized exceeds the protein breakdown (positive nitrogen balance) and phases during which the situation is reversed (negative nitrogen balance) [Fig. 1].
Figure 1: Variations in muscle protein balance over a day. Here, the level of protein synthesis balances that of protein degradation: muscle mass remains constant

2When aiming to increase muscle mass, this balance must remain globally positive over a relatively long period (often more than six weeks) as muscle hypertrophy is a slow process that requires time to achieve significant results (only 1% of the proteins present in the body are renewed every day). Therefore, the increase in muscle mass is achieved through the accumulation of periods during which a positive protein balance is attained.
3Exercise and diet significantly influence the amplitude and duration of these periods of positive or negative balance. For a positive nitrogen balance to be maintained throughout the day, the athlete must stimulate the mechanisms resulting in protein synthesis:
What is the difference between proteins and amino acids?
A protein is a chain of amino acids linked together by peptide bonds. Depending on the protein source (meat, egg, fish, soya, vegetables), the amino acids provided by food may differ. In the context of a training programme aiming to increase muscle mass, it is particularly important to make sure that adequate essential amino acids are provided by food, because these amino acids cannot be synthesized in the body.
by regularly scheduling bodybuilding sessions imposing extensive mechanical stress (heavy weights, repeated efforts, eccentric exercises);
adequate amounts of protein should be consumed regularly;
a hormonal environment favourable to muscle mass gain should be developed by adapting carbohydrate intake based on an appropriate schedule.
How much should protein intake be increased during a programme to increase muscle mass?
4Several studies have shown that the extent to which muscle synthesis mechanisms are stimulated depends on protein intake through food. Indeed, ingesting proteins directly stimulates muscle anabolism by activating protein synthesis. However, there is an upper limit to this physiological reaction. When this is reached, there is no advantage to increasing amino acid intake further, and excess proteins will be directly eliminated in the urine. Distributing protein intake throughout the day (breakfast, snack, lunch, dinner, etc.) is the best way to optimize assimilation of the amino acids provided in the diet.
5It is recommended that athletes who wish to increase their muscle mass plan, it is recommended to plan regular protein intake, at total levels from 1.8 to 2 g.kg−1.d−1 (never exceeding 2.5 g.kg−1.d−1), while simultaneously implementing a bodybuilding programme. Two-thirds of this protein must be provided by a balanced diet; the final third can be provided in the form of protein-based supplements with high biological value. However, this high protein intake must not be maintained for too long, no longer than six months of the year. The absence of negative symptoms should not encourage an excessive consumption of proteins, as this strategy is known not to be scientifically justified. In addition, it is important to remember that nitrogen excretion in the urine (directly generated by an increased consumption of proteins) increases water losses. This explains why it is important to adjust and monitor hydration status in athletes who increase their protein consumption with a view to increasing muscle mass (see Fact sheet No. 10 Hydration, 342).
Is 100 g of meat or fish equivalent to 100 g of protein?
No. Although meat and fish are good sources of animal proteins, and especially of branched-chain amino acids, which are necessary for muscle protein synthesis, 100 g of meat or fish generally provide between 15 and 30 g of proteins.
Why are timing and quantitative distribution of protein intake during the day so important?
6Some studies have shown that the earlier proteins are ingested after exercise, the more efficient the muscle protein synthesis. Significant effects appear up to three hours after the end of a training session. Outside this window, nutritional recovery cannot completely replace the proteins broken down during exercise. Other authors investigated the potential relevance of food intake just before exercise and its impact on outcome. These studies showed that, when food was consumed before the bodybuilding session, an intake of essential amino acids (those that the body cannot synthesize itself and that must be provided by food) had a greater impact on the subsequent protein synthesis than when food was consumed after exercise. This type of strategy decreases amino acid degradation during intense exercise and helps regain a positive protein balance more rapidly using the snack eaten following a bodybuilding session. Indeed, these authors showed that when a source of essential amino acids is eaten five minutes before the session, protein synthesis continues for one hour after exercise (this does not occur when proteins are only ingested after the session). However, we must note that the effect of an increase in amino acids on protein synthesis does not last, even if consistently high blood concentrations are maintained. This observation confirms the advantage of scheduling five to six protein-rich snacks or meals every day to generate an increase in protein synthesis during the recovery period.
Essential amino acids and branched-chain amino acids
There are 20 different amino acids, eight of which are “essential”. These amino acids must be provided by food (they cannot be synthesized in the body). In the context of a programme to increase muscle mass, their intake is necessary, especially the group of “branched-chain amino acids” (valine, isoleucine and leucine), which play a role in promoting muscle protein synthesis.
After a bodybuilding session what snack should be eaten to stimulate protein synthesis?
7Hormonal status plays an important role in controlling muscle protein synthesis. In particular, high insulin levels reduce protein degradation and stimulate the production of anabolic hormones. This explains why combining carbohydrate and protein intake immediately after a bodybuilding session favours an extensive positive protein balance, which results in increased muscle mass after a prolonged training period. Several studies have confirmed that the use of protein and carbohydrate-based meal supplements (with a carbohydrate to protein ratio of 3 or 4) creates a hormonal environment favourable to muscle anabolism, provided the supplement is consumed in the hour following the bodybuilding session. Although, for convenience, this intake can be based on a supplement, it is essential to select commercial products with an anti-doping label, to be sure they are free from banned substances. Finally, we must remember that, in the absence of exercise, insulin does not have a major impact on protein syntheses. Thus, eating a combination of carbohydrates and proteins alone will not result in a significant increase in muscle mass; it must always be associated with an appropriate bodybuilding programme.
Practical applications

1. The bodybuilding session: an essential step

2. Protein requirements

3. Protein sources
Proteins with high biological value: animal proteins
8› The protein quality of this food is similar, but the fat and micronutrient intake is very different. Vary the sources!

* Branched-chain amino acids
Secondary sources: vegetable proteins

4. Protein supplements

5. Dividing up your intake over the day
4 to 6 times during the day
9› 3 meals + 1 to 3 snacks (shortly after or before the bodybuilding session, if possible)
10► Example of protein intake over a day for an athlete weighing 80 kg: 2 g/kg of body weight

Recipe
Pork tenderloin medallion, green lentil and sage cream

Photo credit: Thibaut Ruggeri.

11Serves 2
12Preparation time: 25 minutes
13Cooking time: 30 minutes
14Difficulty:
15Green lentil and sage cream
16■ 120 g green lentils
17■ 50 g onions
18■ 50 g celeriac
19■ 100 g carrots
20■ 10 g butter
21■ 1 chicken stock cube
22■ Thyme, bay leaves
23■ 1 garlic clove
24■Coarse salt
25■ 100 ml semi-skimmed milk
26■ 2 sage leaves
27Chop the vegetables, then sweat them in a casserole whith the butter.
28Add the lentils, the chicken stock, a sprig of thyme, a bay leaf and the clove of garlic.
29Add 1 litre of water and bring to the boil.
30When the lentils are half cooked, season with the coarse salt.
31When fully cooked, drain the mixture.
32Heat the milk and mix it with the warm lentils. Add the chopped sage and season, if necessary.
33Pork tenderloin
34■ 300 g pork tenderloin
35■ Salt, pepper
36■ 10 g olive oil
37Cut the tenderloin into 6 thick slices.
38Season and fry gently in oil.
39Serve the lentil cream topped with the tenderloin in a deep plate.
40Decoration
41■ 10 g yellow curly endives
42■ 5 g chervil
43■ 10 g rapeseed oil
44■ Quality salt
45Decorate with a bunch of curly endives and chervil, seasoned with rapeseed oil.
46Chef’s note
47This dish is rich in protein. It also provides vitamin B6 (two-thirds of the DRI), which is essential for protein metabolism.
48However, it does not contain much carbohydrate and should therefore be served with a carbohydraterich starter or dessert (See “Poached peaches with lemon verbena” recipe, p. 376)
49Nutritional analysis per person
Energy (Cal) | Carbs (g) |
498 | 26 |
Lipids (g) | Protein (g) |
18 | 58 |
Auteurs
PhD. Research Department – French Institute of Sport, Expertise and Performance (INSEP), Paris
PhD. Research Department – French Institute of Sport, Expertise and Performance (INSEP), Paris
PhD. Research Department – French Institute of Sport, Expertise and Performance (INSEP), Paris
Sports Traumatology Centre, Puteaux, France
Medical Department – French Institute of Sport, Expertise and Performance (INSEP), Paris
Le texte seul est utilisable sous licence Licence OpenEdition Books. Les autres éléments (illustrations, fichiers annexes importés) sont « Tous droits réservés », sauf mention contraire.
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