Gain Muscle, Lose Fat

I never thought I’d write an article or blog post with the title “Gain Muscle, Lose Fat.” I promise I’m not selling anything. I just want to pass on some interesting results from a new study by Stuart Phillips and his colleagues at McMaster University, just published in the American Journal of Clinical Nutrition (press release here).

The dilemma is this: most of us have too much fat but not enough muscle. We talk about “losing weight,” but dropping weight can be counterproductive—especially for athletes—if you lose strength in the process. If you’re trying to get down to race weight before a big competition, the goal is to lose fat without sacrificing muscle.

There’s plenty of 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):

Role of protein during weight loss.










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 kilojoule-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 kilojoule 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 kilojoule deficit (which is, by definition, always a temporary state of affairs).

But it’s something to keep in mind at all times, particularly when you’re training hard. To maximise workout gains, your body needs sufficient protein. And it needs it throughout the day, not just in one big dose at dinner.


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