How to Prevent Muscle Loss in a Calorie Deficit
A calorie deficit is required to lose fat.
There’s an abundance of information on this website about fat loss and getting into a calorie deficit, but here’s the very brief summary:
- If you want to lose fat, you need to provide your body less energy than what it requires to maintain your weight.
- You can use this calculator to get an idea of how many calories you ought to be eating to lose fat.
- Prioritise protein and unprocessed foods to feel more full on the same calories and increase the number of calories you burn (via the thermic effect of food).
That’s the short version. If you want a bit more detail about losing fat, then check out this free fat loss guide.
But how do you prevent muscle loss when losing fat?
Why You Need to Keep your Hard Earned muscle!
You spent months, maybe even a year or multiple years, training hard, diligently getting in your protein, tracking your lifts and progressively overloading maybe just to gain a few pounds of muscle. You don’t want to put that all at risk by getting your fat loss phase wrong!
When you’re in a calorie deficit, your body will use whatever is on hand for energy and nutrients, in the absence of food. This isn’t just limited to body fat. Your body can use muscle for energy too, and it will if you let it.
If you lose muscle, you can just end up back at square one. Build muscle and gain fat > lose fat and lose muscle = be right back where you started! No one wants to spin their wheels and waste years!
More Muscle Means You Burn More Calories at Rest
Muscle is metabolically expensive tissue. This means it requires a lot of energy to maintain it compared to other types of tissue. The good thing about this is it means you get to eat more food just to maintain your weight! You’ll have a higher TDEE (total daily energy expenditure) and it will be harder for you to gain fat compared to when you had less muscle!
You also have larger “sugar reservoirs” as muscle is where your body stores most of its glycogen. Glycogen is a substance your body keeps in muscles and your liver as a store of energy it can tap into easily. Glycogen is basically just sugar (glucose) from carbohydrates. Your body’s preferred form of energy is glucose. Any available glucose in the bloodstream will be used for energy when your body needs it. If it’s not available, your body will turn to your glycogen stores or bodyfat stores instead. As glycogen is already glucose and doesn’t have to be converted for use as energy (like body fat) it will be used first.
More Muscle Makes it Harder to Store Body Fat
The reason why it’s harder to gain fat when you’ve got more muscle is because the above process works in reverse too. You won’t store excess glucose in the bloodstream as fat if your body needs to use it straight away. Any excess will be stored as glycogen if the stores aren’t already full. Having more muscle means you have more places to store the glucose. Only once the glycogen stores are full will you store excess glucose as body fat.
Most people never use the glycogen in their muscles because they never perform any intense physical activity where the body needs to tap into those easily accessible stores of energy. Their bodies also never tap into those glycogen stores for energy during a calorie deficit. As a result, they always have full glycogen stores and excess glucose has to be stored as fat.
That is why having more muscle and resistance training makes you healthier and more insulin sensitive (this is a good thing) and it is harder for you to gain fat.
More Muscle Correlates with Longer Life and Better Quality of Life
As you age (after about age 30) you’ll be losing 3-5% of your muscle mass per decade. That might not sound like a lot, but consider a 180 lb thirty year old male with 35% muscle mass. They would have 63 lbs of muscle (which is about average).
If they lose 5% of their mass per decade, they would have 60 lbs of muscle by age 40, 57 by age 50, 54 by age 60, 51 by age 70 and 49 by age 80. That’s 14 lbs of muscle loss. This is why older people are more frail, more at risk of non-communicable diseases and have poor quality of life.
- You lose muscle as you age (sarcopenia).
- Having less muscle means you expend less energy so it’s easier to eat in a calorie surplus and gain fat.
- You have fewer places to store excess energy as glycogen so it’s easier to gain fat.
- With less muscle and more fat daily life becomes much more difficult.
- You move less as a result, and gain more fat as you continue to lose muscle.
This all leads to increasing frailty, decreasing quality of life and greater risk of diseases like diabetes, cardiovascular disease, cancer etc.
How to Prevent Muscle Loss While You Lose Fat
Now you know why it’s vital to hang onto as much muscle as possible. Unfortunately, the body isn’t perfect and it does store some fat as you build muscle. The 100% lean bulk is an elusive thing that will probably evade you forever. At some point during your muscle gaining journey, you’ll probably want to lose fat. Thankfully, there are several things you can do to prevent muscle loss.
1. Be resistance training
If you are lifting weights or performing bodyweight exercises, you are signalling to your body that muscle is still needed. When you’re in a calorie deficit, losing fat, it’s use it or lose it when it comes to muscle.
2. Continue lifting heavy
DO NOT subscribe to the WRONG view that you need to “lift light weights with high reps to lose fat”. This is totally incorrect. How heavy you lift and how many reps you do has absolutely no bearing on whether you gain muscle or lose fat. To lose fat, you need to be in a calorie deficit. You MUST continue lifting heavy so that your body knows your muscle mass is needed and is less likely to use it for fuel.
3. Do not go for a reckless calorie deficit
Large calorie deficits are reckless. More than 20-25% of your TDEE is reckless. You’ll lose weight quickly, but you’ll put your muscle mass at much greater risk. Remember your body only cares about your survival. It doesn’t care about your vanity. If you have a reckless calorie deficit, you are signalling to your body that there is a food shortage. Your body will increase stress hormones as it thinks it will help you to survive. You’ll be very food driven so you’ll likely experience intense cravings and the whole diet will just be harder to stick to. You’re more likely to have nutrient deficiencies and feel like crap. Your immune system may be lowered and you’re more likely to get sick. These things will make you more likely to snap and binge, negating the whole point of the calorie deficit in the first place.
What’s more important for this article, however, is that a large calorie deficit is more likely to lead to muscle mass loss than a moderate calorie deficit. This is because your body knows the muscle requires more energy to sustain it. It will get rid of the muscle mass so you can survive on fewer calories.
Avoid all this. Keep your calorie deficit to 20-25% of your TDEE. You can get a rough calculation of your TDEE here.
4. Keep Your Protein Intake High
Protein is required to repair muscles. If you’re damaging them with lifting (as you should be, use it or lose it, remember?) the protein has got to come from somewhere to repair them. Your body also requires protein for other growth/repair like skin, nails and other tissues, and for enzymes, hormones and other body chemicals.
I know you desperately want to lose fat, but don’t be tempted to drop your protein intake so you can reduce calories further! It’s a bad idea. If you’re not getting enough protein in your diet, your body will find those amino acids from somewhere else. Oh look, there’s all this muscle hanging around we can tap into!”
Note: I get a lot of requests from Indian followers/readers, following an Indian vegetarian diet, asking about how to hit a high protein goal without meat or fish. While I’m not an expert in this myself (not being from India), I can highly recommend this blog post on increasing protein intake with a vegetarian Indian diet.
5. Reduce Lifting Volume
If you’re in a calorie deficit, the chances are you’re not going to gain much, if any, muscle. Your priority should absolutely be hanging onto the muscle you already have.
Continuing with a high volume routine is insanity at this point. All you need to do is lift at high intensity (heavy weights) so your body knows the muscle is still needed, then stop! A couple of work sets taken near failure of a compound lift is enough per body part!
If you continue smashing your muscles to pieces with endless exercises, sets and reps multiple times per week, the chances are good that you won’t be able to recover. The quality of your sessions is going to go downhill fast and it’s quite likely you won’t have the nutrients available to repair your muscles. You’re breaking the muscles down in the gym, but you’re not repairing them adequately outside of it. This will lead to the slow erosion of muscle tissue over time.
Bonus tip! You want to be taking creatine! It will provide a noticeable boost to your strength. Any creatine monohydrate will do. See here for the benefits of creatine monohydrate vs HCL.
If you’re making these mistakes with your routine, get a better one!
The number one mistake I see is people doing WAY TOO MUCH in the gym.
I’ve got 7 free workout programs you can download here. If they don’t seem like they contain enough work, you probably need to get on one of them.