The study looked at a group of “college aged resistance trained men”, and put them on either a conventional Western diet or a VLCKD.
The conventional diet was 55% carbohydrate, 25% fat, and 20% protein, similar to what lots of people eat, though a bit higher in protein, a bit lower in fat.
The low-carb diet was 5% carbohydrate, 75% fat, and 20% protein.
Note that protein, the main macronutrient responsible for muscle growth, was the same in both groups. Both groups did resistance training three times a week for 11 weeks.
The very low carbohydrate group gained twice as much muscle as the conventional group, 4.3 kg vs 2.2 kg.
The very low carbohydrate group lost 50% more fat than the conventional group, -2.2 kg vs -1.5 kg.
It should be noted that this is from a “poster presentation” at a conference, and as such has not been peer-reviewed.
What could be going on here? The extra fat loss was not a surprise to me. Low-carbohydrate diets have a much better record at fat loss than do conventional diets. However, this was not a weight-loss trial, and presumably the participants ate as much as they wanted.
There are several ways that muscle gains could be greater when a ketogenic diet is combined with weight training. 2
Most bodybuilders will tell you that you need carbohydrates to build muscle, or that it’s more effective with carbohydrates, but there are several reasons for thinking that is not the case.
Protein alone and not carbohydrate is responsible for muscle growth and, once the metabolism is adapted to burning fat, intense exercise can be performed on a low-carb diet.
One reason for thinking that carbohydrates make for better gains, and this may be a real consideration, is that people often spontaneously decrease calorie intake on a very low-carbohydrate diet. This may account for much of this diet’s efficacy in fat loss. But if you’re looking for those gains, you need to eat enough, and it could be that many low-carb eaters do not.
But it seems for most people a VLCKD could be just the ticket for muscle gains and fat loss when combined with regular resistance training.