EAA (essential amino acids) during cutting: does it help

Cutting is a period when the task sounds paradoxical: to get rid of fat without losing muscle. EAA are often advertised as "muscle protection on a diet" with zero calories. The editorial team looked into what happens to muscle protein in a calorie deficit, whether EAA really are "calorie-free" and how much the supplement helps to preserve your shape.

What happens to muscles in a calorie deficit

When less energy comes in with food than the body expends, it is not only the amount of fat that decreases. A calorie deficit reduces basal muscle protein synthesis, and some amino acids are used as a source of energy. Without protective measures, the share of lost lean mass in the total weight loss can be significant.

The degree of loss depends on several factors: the size of the deficit, the duration of the diet, the initial percentage of fat, the level of training and, of course, the amount of protein in the diet. The leaner a person is and the more aggressive the deficit, the higher the risk of losing muscle specifically.

The review by Helms, Aragon and Fitschen (2014), devoted to the preparation of natural bodybuilders for competition, advises avoiding too fast a rate of weight loss and aiming for approximately 0.5–1% of body weight per week. A slower rate better preserves muscle mass and strength.

So the main question of cutting is not "which supplement to buy" but how to combine a moderate deficit, strength training and sufficient protein. EAA can be part of this system, but not its foundation.

Protein as the main protector of muscles on a diet

The most convincing data concern total protein intake. In a randomized study by Longland et al. (2016), young men spent four weeks in a significant calorie deficit with intense training. The group with higher protein intake (2.4 g/kg) not only preserved but even somewhat increased lean mass and lost more fat than the group with 1.2 g/kg.

Pasiakos et al. (2013) showed something similar: with a calorie deficit, protein intake at a level about twice the norm preserved lean mass better than the usual norm, whereas triple the norm gave no additional advantage. That is, there is a "reasonable ceiling" above which there is no point in increasing protein.

Helms et al. for athletes in a deficit propose 2.3–3.1 g of protein per kilogram of lean mass — a higher range than for a gaining period. The logic is simple: in a deficit the body more actively "burns" amino acids, and to preserve muscle more substrate is needed.

It is important that in these studies protein came mainly from food and protein drinks, not from isolated EAA. That is, the main conclusion is "enough protein," and the form in which it arrives is secondary.

Where EAA fit in here

EAA are a concentrated "anabolic" component of protein: all nine essential amino acids without the non-essential ones, carbohydrates and fats. Studies by Wolfe's group showed that it is EAA that stimulate muscle protein synthesis, and non-essential amino acids are not necessary for this (Volpi et al., 2003).

During cutting this gives a theoretical advantage: the same stimulation of synthesis can be obtained from a smaller amount of calories than from complete protein. If the calorie "budget" is very tight — for example, in the final weeks of preparation for competition — this difference can be noticeable.

However, complete protein has its own advantages during cutting. It satiates better, is absorbed more slowly, and whole foods provide micronutrients and fiber. The feeling of satiety in a calorie deficit is not a trifle, since it is precisely hunger that most often "breaks" a diet.

So EAA are not "better" than protein, but different: it is a tool for specific situations when an anabolic signal is needed with a minimum of calories and volume.

The myth of "zero calories" and fasted training

On many EAA labels it says "0 kcal." This is related to the labeling peculiarities of some countries, where free amino acids are not always counted in the calorie content. But physiologically, amino acids are energy substrates: they can be oxidized or converted into glucose. Approximately they provide about 4 kcal per gram, like protein.

Therefore 10–15 g of EAA is not "zero" but approximately 40–60 kcal. Against the background of a daily diet this is not much, but if a person drinks several servings a day, the "invisible" calories add up. During cutting they should be taken into account in the overall balance.

A popular practice is to take EAA before fasted cardio in order to "protect the muscles." Taking amino acids formally interrupts the fasted state, so the training is no longer entirely "fasted." There is little evidence that fasted cardio in itself gives an advantage in fat burning with the same daily calorie balance.

• The calories of EAA are real — take them into account in your daily count.
• Taking EAA before a morning workout shifts the body from a state of fasting into a state of amino acid intake.
• For body composition, the decisive factor is the daily balance of energy and protein, not a separate "trick."

This does not mean that morning EAA are useless. If it is more comfortable for a person to train without a full breakfast, a small serving of amino acids can be a reasonable compromise between well-being and providing the muscles with substrate. It is just worth perceiving it as part of the daily protein, not as a way to "cheat" the metabolism.

A practical scheme: when EAA are justified

The editorial team highlights several situations where EAA during cutting make practical sense. The first is a very strict calorie budget, when every 50–100 kcal counts and it is already hard to add protein from food without exceeding the calories.

The second is training between meals or long breaks in eating. A serving of EAA before or during training gives an anabolic signal without loading the stomach, which is especially convenient for those who tolerate food poorly before a load.

The third is a plant-based diet. During cutting it can be hard for vegans to get enough quality protein without the extra carbohydrates and fats that come "as a set" with legumes or grains. EAA help balance the profile of essential amino acids.

In studies of muscle protein synthesis, EAA servings of approximately 6 to 15 g were used, with a sufficient amount of leucine. For an ordinary dietary supplement it is reasonable to stay within this range and not replace main meals with it. And if the daily protein is already at 2 g/kg or higher, the additional effect of EAA will most likely be minimal.

Editorial conclusions

During cutting, muscles are protected primarily by a moderate rate of weight loss, strength training and increased protein intake. These three factors have a convincing evidence base; EAA are only a supplement to them.

The advantage of EAA is a higher "anabolic density": more stimulation of protein synthesis per calorie. But "zero calories" is a myth, and amino acids need to be taken into account in the balance.

EAA make sense with a very strict calorie budget, training far from meals and a plant-based diet. But if there is plenty of protein in the diet, the additional effect will be small.

We also recommend reading "EAA (essential amino acids) during bulking: does it make sense," "EAA (essential amino acids) for women: are there any peculiarities" and "EAA (essential amino acids) and sleep."

References

1. 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.
2. Longland TM, Oikawa SY, Mitchell CJ, Devries MC, Phillips SM. Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial. Am J Clin Nutr. 2016;103(3):738–746.
3. Pasiakos SM, Cao JJ, Margolis LM, et al. Effects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial. FASEB J. 2013;27(9):3837–3847.
4. Volpi E, Kobayashi H, Sheffield-Moore M, Mittendorfer B, Wolfe RR. Essential amino acids are primarily responsible for the amino acid stimulation of muscle protein anabolism in healthy elderly adults. Am J Clin Nutr. 2003;78(2):250–258.
5. Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.
6. Phillips SM, Van Loon LJC. Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci. 2011;29(Suppl 1):S29–S38.