Rauch et al  assigned 26 men to a periodized 10 week resistance training routine and either a 75% fat, 5% carbohydrate ketogenic diet (VLCKD) or a conventional 55% carbohydrate, 25% fat diet.
The men assigned to the 75% fat, 5% carbohydrate diet gained almost twice as much muscle in 10 weeks compared to those assigned to the 55% carbohydrate, 25% fat diet.
Manninen  reports that VLCKD may reduce muscle catabolism by the following mechanisms:
1 . Raising adrenaline levels. Low blood sugar stimulates adrenaline release, and adrenaline inhibits proteolysis of muscle.
2. Raising ketone body levels. Very low carbohydrate intake raises ketone body production, and ketone bodies inhibit oxidation of amino acids.
3. Raising growth factor levels. A high protein ketogenic diet appears to raise levels of skeletal muscle expression of IGF-I mRNA about 2-fold.
4. High protein intake. High dietary protein intake stimulates muscle protein synthesis.
Thus, a VLCKD may be both more anticatabolic and anabolic than a high carbohydrate, low fat diet.
1. Rauch, Jacob T et al. “The Effects of Ketogenic Dieting on Skeletal Muscle and Fat Mass.” Journal of the International Society of Sports Nutrition 11.Suppl 1 (2014): P40. PMC. Web. 2 May 2017.
2. Manninen, Anssi H. “Very-Low-Carbohydrate Diets and Preservation of Muscle Mass.” Nutrition & Metabolism 3 (2006): 9. PMC. Web. 2 May 2017.