Building muscle and losing fat
There’s plenty of folk wisdom about how to do this, including making sure you get lots of protein. Phillips and his team put this idea to the test, and a very rigorous test it was.
The study involved 40 overweight young men who were put on a supervised diet (all meals provided) and exercise program (six days a week, including two days of circuit resistance training, two days of high-intensity bike intervals, one day of bike time trial, and one day of plyometric body-weight circuits) for four weeks. The food provided 40 percent fewer calories than their calculated requirements (ugh).
The subjects were divided into two groups, with just one key difference between them: one group consumed 1.2 grams of protein per kilogram of body weight, while the other group consumed 2.4 grams of protein per kilogram of body weight. The lower protein dose was close to what the subjects typically consumed (but still higher than the Recommended Dietary Allowance); the higher dose was triple the RDA.
Here’s what the results looked like after four weeks, for total body mass (BM), lean body mass (LBM), and fat mass (FM):
In terms of total weight showing on the scale, the two groups were about the same. But the higher protein group actually gained muscle while on a severely calorie-restricted diet, and also lost more fat. That’s a very impressive result.
Now, what does this mean in practice? As Phillips acknowledges in the press release, this is a very tough program—both the calorie restriction and the hard exercise routine. In a sense, the experiment was more of a proof of principle than a template for sustainable living. They’re planning future experiments with a more tolerable regimen.
To me, the main takeaway is further confirmation of the important role that protein (in combination with exercise) plays in triggering muscle growth and repair. As this study shows, it’s particularly clear when you’re in caloric deficit (which is, by definition, always a temporary state of affairs).