How to build muscle mass and lose body fat at the same time - Body Recomposition

Losing body fat and building lean muscle mass at the same time? Sounds impossible, doesn't it?

But it's actually possible. Although putting on muscle mass while losing body fat is tricky, it is possible with a scientific approach to dieting and training, if you're just starting out with weight lifting.

How muscle growth works

Protein degradation and protein synthesis are two of the most fundamental biological processes that occur in our muscle cells.

Protein degradation (also called Proteolysis) is the breakdown of proteins in your muscles into their smaller components, namely amino acids and peptides.

Protein synthesis on the other hand, is a process where individual cells build their specific protein from smaller components. Basically muscle repair and growth.

Normally, if you're healthy and eat a balanced diet, your muscle tissue remains quite stable. Meaning, the ratio of synthesis and degradation is more or less equal (you don't gain or lose a huge amount of muscle mass in your everyday-life).

If you aim for more muscle mass though, synthesis rates must exceed degradation rates. Hence, your body must build more muscle than it loses.

But how? First, you have to train your muscles. Heavy weightlifting causes damage in muscle cells, after which the body repairs the broken tissue - as long as enough dietary protein was consumed to trigger muscle protein synthesis.

How fat loss works

Actually, losing fat is the simplest part of the story. The problem is, that there is too much Bro-Science out there and people don't question it.

You don't have to figure out what a 'good' food or a 'bad' food is. Stop with the obsession over clean eating. Balance and moderation is the key. In the end all that matters, when it comes to body fat reduction, is a negative energy balance (less calories consumed than you burn). That's it. No, carbs aren't evil. Neither are fats or protein. Don't avoid them just because someone told you to.

And no, there is no magic 'eating schedule'. It doesn't matter, if you eat 3, 5, 12 or 20 meals per day, as long as you stay within your calorie target. It also doesn't make any difference, if you drink a post workout-shake the minute you're done in the gym. Get a decent, high carb-high protein meal in, within 1-2 hours after you've finished your workout and you'll be fine.

Who can rebuild body composition and who can't?

Never done weightlifting before? Than you are the perfect candidate for adding muscle mass while reducing body fat!

If you're already training for several years, you'll have a hard time and should consider the 'bulking' and 'cutting' approach, in which you have separate periods for adding muscle mass and reducing body fat.

Build lean muscle mass and lose body fat at the same time

Learning how to rebuild your body composition comes down to these two points:

  1. Eat at a moderate calorie deficit for fat loss
  2. Get stronger in the gym

That's it!

Moderate caloric deficit

Since you want to lose body fat you still have to be in a caloric deficit - but a moderate one. Putting yourself in a large deficit, can lead to muscle loss and lack of energy (both things you don't want, since you have to train hard).

What is the optimal caloric deficit? Aim for 10-15% below your caloric maintenance level. Let's say my caloric intake for maintaining my weight would be 2300 calories per day.

Creating a caloric deficit of say 10% means my new caloric target is around 2070kcal per day.

You can use the calculator down below to figure out your maintenance calories and go from there.

Based on your calculated daily calorie target you can now create your own meal plan.

Macronutrient distribution

This is actually pretty simple. Since you want to reduce body fat and add lean muscle mass, you have to increase your protein intake.

An adequate amount of quality protein with each meal is important to promote protein synthesis and maintain muscle mass.

Furthermore you need a moderate intake of carbs, to fuel your workouts and go hard! Opt for complex carbs such as rice, oats and potatoes.

They will help to control your portion sizes, boost leptin levels and keep you feeling full longer!

Eat your carbs around your workout time, to fuel your workouts. But account for digestion! Eating 100g of oats 30 minutes before your training is stupid. You'll still digest the food during your workout. Aim for 1-1.5 hours in advance.

Your fat intake is limited to the amount you need to stay healthy. Focus on healthy fats, such as fish oil, coconut oil, nuts, seeds, avocado and eggs.

Here is your macronutrient breakdown per day:

  • Protein: 2g per kg bodyweight/1g per pound bodyweight
  • Fat: 0.5g per kg bodyweight/0.2g per pound bodyweight
  • Carbohydrates: The remaining calories, based on your calorie goal (see calculator above)

Remember: protein and carbs have 4 kcal/g, fat has 9 kcal/g.

Heavy full body weightlifting exercises

Isolation exercises and high-rep workouts are NOT the key to getting shredded. Bro-science alert!

You get lean when your body fat percentage is low enough, which happens through a caloric deficit. There is no style of training, that makes you look more "toned" than another.

Focus on heavy compound exercises. When you're hitting the gym, do squats, deadlifts, military presses and bench presses at least once every week. Aim for a 4-8 rep range, so go heavy! If you train your muscles with little intensity, you won't trigger muscle repair. Which means you might as well stayed at home.

Don't even think about biceps curls, damn crunches and triceps extensions. That's not a heavy workout!

Skip the treadmill

We see it all the time: People who spend literally hours on the treadmill to lose body fat. Please, don't do that! Until a certain point you don't have to do cardio at all. If ever.

Sooner or later you might reach a point where your weight loss plateaus and you have to burn more calories to keep the fat loss going. Since you want to build muscle mass, you have to be very careful with cutting more calories.

When that time comes, don't hop on the treadmill for 1 to 2 hours everyday. Yes, you will burn energy and lose fat, but you also will lose your hard earned muscle mass and feel sluggish all the time. Normal cardio is muscle wasting!

Instead do HIIT (high intensity interval training). In fact, 4 to 6 all-out sprint intervals burn more than 60 minutes of incline treadmill walking. Amazing, right?

Not convinced yet? It's also proven that HIIT sessions increase your metabolic rate for up to 24 hours afterwards, spike your growth hormone levels (meaning, it accelerates muscles growth) and increase fat oxidation in your muscles. Plus HIIT can actually build muscle, rather than burning it.

Don't do more than 2 sessions per week and no longer than 30 minutes per session. As your conditioning improves, you will be able to expand the intervals and increase the intensity. Aim for a bike-based workout, which is better for your joints than the treadmill.

Rest well

I can't stress it enough: Sleep is one of the most important aspects for both, fat loss and muscle growth. You need proper regeneration. Rest is part of the game!

Not getting enough sleep might also increase cortisol levels, which has a negative impact on fat loss and muscle gain.

There's no "one size fits all", even when it comes to how much rest the body needs. According to the National Sleep Foundation, adults should aim to get 7 to 9 hours sleep on average to be well rested. However, training hard will increase your need for sleep, so rest more if your body feels worn down.


Keep in mind, that supplementation is only helpful to get the last 1% out of your body. It's definitely not a magic bullet and you don't need it, but the right supplements can help.


Creatine helps you to build muscle and strength, even when you are in a caloric deficit.

However, some people feel the difference when taking creatine and some are non-responders. If you eat enough red meat though, you don't need it at all.

Whey protein

As I said before, supplementation is not necessary. But actually whey protein is one of the cheapest quality protein source out there (if you buy it online from the manufacturer, which everybody should do!).

And it's a pretty easy and delicious way to get your protein in, especially when you struggle with eating a lot of protein.

I love to make healthier desserts with whey protein, especially when I'm cutting. It's nice to have something sweet to look forward to.

But don't replace meals with a protein shake. Whey is not good for that. Only consume whey shakes post workout and use whey as an ingredient for other meals (e.g. porridge).

Again, if you eat enough protein already, no need for whey whatsoever!

Other than those two, you only add supps that you lack in from your everyday diet. Mainly Omega 3 if you don't eat fatty fish, vitamin C if you don't eat enough fruits/veggies and vitamin D3 if you don't get enough sun light.

No BCAAs, pre-workouts or CLA required. Keep the money and rather buy decent food!


See, it's totally doable to build muscle and lose body fat at the same time. And it seems pretty easy, doesn't it?

A slight caloric deficit paired with heavy (really heavy!) lifting as a beginner can lead to fat loss and muscle gain at the same time, for up to 1 year. After that, your body is too used to training and you have to switch to cutting and bulking.

But don't expect insane changes over night. A "recomp" takes time. Good luck!

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