Although a lot of real-world evidence and scientific studies on the composition of body tissues show that you can build muscle mass in a calorie deficit, the myth persists that muscle mass can only be built in excess calories. Accordingly, it is legitimate and even necessary to do so-called bulk (ing) phases. That means phases with increased calorie intake, in which you gain both fat and muscle mass. In order to then go back on the diet again, i.e. burn as much fat as possible without losing much of the muscle mass that you have built up.

Taking in calories can make a lot of sense if someone who is very slim, or generally someone who doesn’t mind building up a few pounds of fat, wants to build muscle and become heavier. However, it is not necessary to consume an excess of calories in order to build muscle at all if there is still enough body fat from which the body can feed or if you want to keep your body fat percentage.

SchmieDer Philipp Born has built up 3.6 kg of clearly visible muscle mass over a period of 24 weeks, reducing his body fat percentage by 1%.

The crucial mistake in the logic of impossible muscle building with a negative calorie balance is as follows:

A calorie is a unit of energy – not a unit of weight!

This becomes clear when you look at the energy content of the individual macronutrients:

Protein: 4.1 kcal./g

Carbohydrates: 4.1 kcal./g

Fat: 9.3 kcal./g

Proteins and carbohydrates contain less than half the energy per gram like fat. With the same weight, fat contains much more energy. It is no different from body tissue.

1 kilogram of body fat contains approx. 7000 kcal. The difference to pure fat, which contains 9300 kcal./kg, is that body fat cells also contain some protein and liquid in addition to fat.

1 kilogram of muscle mass only contains approx. 1200 kcal. Also, a difference to pure protein, since a muscle consists mostly of water (about 80%).

That means if you have a deficit of 500 calories, i.e. 500 kcal, every day for two weeks. If you consume less than you consume, you would have a deficit of 7000 kcal. achieved in these two weeks.

However, if you gain a kilogram of muscle mass in these two weeks, you add 1200 kcal. to his calorie balance.

The calculation looks like this: -7000 kcal + 1200 kcal. = -5800 kcal.

Note: These numbers are not correct for every person on the calorie because we are all individually different. It is just a calculation example to make it clear why you can burn body fat and build muscle mass at the same time. However, the relationship between the energy content of the different body tissues should have become obvious.

So you are still in a big caloric deficit and have lost 1 kg of body fat and built up 1 kg of muscle mass. But the scales show -1 kg fat + 1 kg muscles = 0 kg difference in two weeks because energy is not a unit of weight. Stored energy in the form of one kilogram of fat was lost and (less) stored energy in the form of one kilogram of muscle mass was added.

Changing the diet here now, since supposedly nothing has happened, would be a mistake. Therefore, I use the YPSI skin fold measurement next to the scale to see whether fat or lean mass is lost or built up.

If you feel better, get stronger in the gym and your pants widen, these are good signs that you are on the right path – even if the scales cannot show it.

Do you want to get leaner, stronger and fitter?

Then you can now easily arrange a free and non-binding initial consultation for yourself!