For an increase in muscle mass to occur, protein synthesis must be greater than protein degradation, giving rise to what is known as a positive nitrogen balance, although having a positive balance does not directly mean that there is a gain in muscle mass (this would be the subject of a separate post).
Therefore, it has always been assumed that suppressing protein degradation after training will contribute to an increase in the positive protein balance and, therefore, to an increase in muscle mass.
That assumption would be true if all the inhibition of muscle degradation were exclusively of intact myofibrillar proteins and not of damaged myofibers. We need to know that degradation of these proteins is likely to be an important part of the training adaptation process to remodel and recondition muscle fibers.
Therefore, nutrition interventions that seek post-workout inhibition of protein degradation (protein catabolism) do not really make sense, at least theoretically as a concept. In fact, incessantly seeking to inhibit protein degradation would be a detriment rather than a benefit in improving our muscle regeneration and growth.
Post-strength training carbohydrate consumption, apart from replenishing glycogen stores, has been suggested to be a good option not to stimulate protein synthesis (something that high biological value protein consumption already does in abundance) but to suppress protein degradation by decreasing cortisol and increasing insulin, which ultimately decreases protein degradation. It is also common to consume intra-workout supplements with the aim of decreasing muscle protein degradation.
But, as I said, it can be a mistake to try to limit muscle protein degradation at all costs with intra- or post-training nutritional interventions.