Can You Build Muscle In A Calorie Deficit?

build muscle in calorie deficit

Building muscle can happen in a calorie deficit, but it is more complicated. When you eat enough food to meet your daily caloric needs, you supply your body with enough calories or energy to fuel all of its processes, including muscle growth. When you are in a calorie deficit, your body does not have enough energy to run all functions, including muscle growth. This energy deficit means the body has to get the extra energy it needs from somewhere else, and this is usually stored body fat. But the body can also down-regulate specific body processes such as muscle growth to conserve energy. In rare cases, the body can break down muscle to release amino acids, which the body then converts to energy.

What is a calorie deficit?

Technically speaking, when you are in a calorie deficit, you eat less food than your body needs to function correctly. When your body is in a caloric deficit, your body uses fat as an energy source, resulting in weight loss since it draws from its fat reserves. If you are trying to build muscle, your caloric deficit shouldn’t be so high that you can’t lift weights properly. Instead, it would be best to eat a number of calories that will cause your body to go into a caloric deficit environment, but not so few calories that you will lose weight too rapidly and not be able to exercise and recover properly.

A good starting point for a calorie deficit where you can lose fat and gain muscle simultaneously is 500 calories under your daily caloric needs. So, for example, if your daily caloric needs are 2,000 calories per day, you would subtract 500 calories, which would mean you would consume 1,500 calories per day. This size of a deficit is enough of a deficit to get weight loss and a small enough deficit that you can still build muscle simultaneously as your weight loss. It is important to note that when you decrease your caloric intake, you have to increase your protein intake to maintain muscle mass and prevent muscle catabolism. If you are trying to gain muscle while losing fat, you absolutely have to increase your protein intake in a calorie deficit environment.

What makes muscles grow?

Muscles grow by being stimulated or challenged to deal with levels of resistance or weight that they are not used to. This stimulus causes microtrauma in the form of tearing in the muscle fibres. The body responds by repairing these micro-tears, and the body repairs the fibres and makes them larger and thus stronger so that they can adapt and handle the new stimulus or weight better in the future. This process of the muscle fibres growing in size is called muscle hypertrophy. The body can also adapt to increase muscle stimulus by creating new muscle fibres, and this process is called muscle hyperplasia. Muscle hyperplasia is rare, and the usual adaptation from training or working out is hypertrophy or the growth in the size of the already existing muscle fibres.

We have explained the basics of how muscles grow in size to give you an idea of how energy-intensive this process can be and how the body will need a lot of protein and amino acids to facilitate the repair and growth of the muscle fibres. So, you need to ensure you do not drop your caloric intake too drastically, and you need to ensure you are consuming a large enough amount of protein to facilitate muscle repair.

Can you build muscle in a calorie deficit?

Scientific studies show that you can gain muscle while in a calorie deficit. It is not easy to do and requires careful calculation of your body’s daily caloric needs, how much of a caloric deficit you will be in, and how much protein you need to consume to prevent muscle catabolism or breakdown.

The pursuit of losing weight and gaining muscle simultaneously is often referred to as body recomposition. A good example of real-world body recomposition would be a chubby boy who, once he hits puberty, the hormonal cascade completely changes his body. We have all seen this before, where a boy hits puberty, and in a short period of time, he loses all his fat and puts on a large amount of muscle at the same time. This is a perfect example of body recomposition.

So can you build muscle and lose fat at the same time? If you are not a teenage boy with the perfect cascade of anabolic hormones, the answer is yes. However, it is tough and tricky to pull off successfully.

Numerous studies prove that you can gain muscle on a calorie deficit. One such study demonstrated that you could build more muscle and lose more fat by simply increasing your protein.[1] The following study specifically looked at high protein intake during a reduced calorie intake and its effect on weight loss and muscle mass.[2] The study concluded that higher protein intake along with a calorie deficit could result in more significant fat loss and muscle gain. 

can you build muscle on maintenance calories?

You can most certainly build muscle on maintenance calories, and it is a lot easier than trying to build muscle on restricted calories. Maintenance calories is a term that means you are taking in exactly enough calories to cover your body’s energy needs. So there is no excess in calories and no deficit in calories either. If you are eating and taking in enough calories to cover your body’s energy needs, then your body will have enough energy to expend on building muscle.

Summary of building muscle in a calorie deficit

As you can see from the studies referenced in this article, it is entirely possible to build muscle when in a caloric deficit. Building muscle while in a calorie deficit is not easy and takes knowledge and willpower, but it is certainly possible.


  1. Regional, but not total, body composition changes in overweight and obese adults consuming a higher protein, energy-restricted diet are sex specific – PubMed (
  2. Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial | The American Journal of Clinical Nutrition | Oxford Academic (

The content and information contained within this article is not intended to be taken in anyway as medical advice. You should always consult your doctor before starting any exercise or nutritional supplement etc.