‘Let us help you build muscle while you lose fat’, ‘Lose fat and gain muscle at the same time’, ‘Build muscle while you shred’ are slogans often used by fitness professionals all over the world to promise the best of results to their clients. The ‘outdated’ practice of ‘bulking’ and then ‘cutting’ has been abandoned ages ago while being replaced with the claim that both things can occur at once (ie. Gaining Muscle and Losing Fat), but how much of it is actually true?
Can We Build Muscle and Lose Fat at the Same Time?
We shall explore this topic with a brief overview of the underlying concepts to this claim while skimming through the relevant studies in order to conclude whether this really is possible or not.
So first things first, where does this claim draw its foundation? The old claim of ‘bulking’ and then ‘cutting’ is based on the concept of Calories in and Calories out (CiCo). If Ci>Co, you gain weight and if Ci<Co, you lose weight. While this is true, it fails to elucidate what sort of weight is being gained or lost. The overall body mass has two variables, muscle mass (lean body mass or lbm), and fat mass (netweight) which the CiCo theory holds directly proportional. So you could either be losing muscle mass, fat mass or both and in terms of gaining, the same.
However, it is possible to make the two variables inversely proportional to each other by manipulating factors external to the body as research has shown. A study conducted by McMaster University, published in The American Journal of Clinical Nutrition, 2016, found that an overall caloric restriction (ie. a calorie deficit where Ci<Co) of 40% and Resistance Training for 4 weeks, 6 days a week on both study groups (40 subjects), where one group was a ‘high protein group’ and the other ‘normal protein group’, helped both groups lose fat while increasing muscle mass. However, the ‘high protein group’ showed a greater increase in lean body mass than the ‘normal protein group’, while decreasing fat mass. So all in all, both groups reduced body fat % while adding on to their lean body mass by manipulating ‘protein’ and training in a caloric deficit.
Coming to our conclusion, yes it is true that you can build muscle and lose fat at the same time as this study proves amongst numerous others, however, great consideration has to be given to training and the ratio of macro-nutrients that constitute Ci in a deficit. High protein about 2-3g/kg of lbm, 15-30% from fat and the remainder from carbs usually does the trick with a good workout program.