Monday Mar 11, 2024

How to Build Muscle and Lose Fat - at the same time!

You’ve probably heard someone argue that achieving muscle growth and fat loss in the same day is physically impossible because of thermodynamics. The argument goes as follows.

  1. To build muscle, you must store energy. To lose fat, you must burn energy.
  2. When you are in energy surplus, your body stores energy. When you are in a deficit, your body loses energy.
  3. Therefore, you must be in energy surplus to gain muscle and in a deficit to lose fat.

The first two points, the premises, are true. They refer to the first law of thermodynamics (‘movement of energy’), also called the law of the conversion of energy. This law means energy cannot just disappear. It has to go somewhere. Building new fat or muscle cells requires energy and breaking them down releases energy. However, point three, the conclusion, is false.


Why? Because muscle and fat tissue are different functional compartments in the body. As a result, your body directs calories towards muscle and fat mass independently. Researchers call this calorie partitioning and the resulting change in fat and muscle mass are expressed as a P-ratio.


The body does need other substrates to build muscle mass of course. You need building blocks to build a house. Let’s look at what exactly the body needs.  


So what do we need to build muscle mass?

  1. Lots of water (H2O). You can drink plenty of that during a cut, so no problems there.
  2. Several kinds of protein. Again you can eat a lot of protein on a fat loss diet, so no problems here either. For the DNA and RNA we also need nitrogen and phosphate, but those can be derived from dietary protein.
  3. Glycogen (carbs) and triglycerides (fat). This basically just comes down to energy, because glucose and fat are non-essential nutrients that can be created by the body itself. We need a lot more energy too, because the protein synthesis for the muscle building process is an energy costly process itself.


In short, we need protein, water, and energy.

Where do we get the energy?

Easy. Your body has plenty of that – its that body fat you are trying to lose. They say an average woman has 2 months of fuel on her body in the form of stored body fat – so that is plenty of fuel! 

Thus, as long as your body has sufficient stimulus to build muscle mass, which it has if your training program is optimized, it has both the means and the will to build muscle mass while simultaneously losing fat.


Similarly, your body is capable of storing fat while burning muscle. The conservation of energy law only means that you must gain energy in an energy surplus and lose energy in a deficit. It says nothing about how these calories are partitioned or about how your body composition changes.

There is an awesome study that used overweight police officers, they were put on a low calorie diet but with surplus protein and they did resistance training for 12 weeks, On average they lost 9.3 lb of fat and gained 8.8 lb of muscle

This is what we call “recomp” (recomposition) when a bodyweight can stay pretty much unchanged but the composition changes. In this case the police officers weight did not change very much but they had tremendous fat loss and muscle gains at the same time.

Newbies often experience “recomp” but so too can experienced lifters.

Indeed more muscle can be built in a greater energy surplus and indeed gaining muscle in a deficit is harder for an experienced trainer, but with sufficient stimuli and enough protein you should expect to build muscle on a fat loss diet.


After all we know that the body can gain fat and lose muscle at the same time when in a surplus

Why not then for the body to lose fat and gain muscle in a deficit? The macros, training, rest and recovery just need to be inline and it will happen.


This is what MUSCLE MONTH is all about - building muscle and staying lean, or getting leaner.

I would never do a bulking program, so I would never ask that of my clients


But Muscle Month starts really soon March 31 - April 27

If you missed it, please send me your contact info and I will put you on my mailing list





Comments (0)

To leave or reply to comments, please download free Podbean or

No Comments

Copyright 2023 All rights reserved.

Podcast Powered By Podbean

Version: 20240320