To burn fat you have to create an energy deficit. You do this mainly through diet, possibly with some help from cardio. But how big or how small should that deficit be, if you also want to keep your hard-earned muscle mass?

Key points:

1. During the cut you try to lose fat while maintaining your muscle mass.

2. To maintain muscle mass, you must continue to train as intensively and voluminously as possible.

3. To lose fat you need an energy deficit. You create that first and foremost by eating less. In addition, you can also move a little more, in the form of cardio and/or upgrading your NEAT.

4. Cutting is a lot harder than just losing weight. If the energy deficit becomes too big, there is a risk of loss of muscle mass. If the energy deficit is too small, the cutting takes an unnecessarily long time, so that you can no longer bulk for a longer period of time (build muscle mass),

5. With an energy deficit of 20-25% of your maintenance level, you probably realize the most fat loss while retaining muscle mass. With this deficiency you lose 0.5 to 1% of your body weight on a weekly basis.

6. Keep your protein intake high during the cut, but don’t go higher than necessary (1.8-2.7 g/kg/day) and don’t eat more fat than strictly necessary (0.5-1 g/kg /day), so the rest of your calories can go to carbohydrates, the primary source of energy for strength training.

7. Your strength performance during training is the most important indicator of possible muscle loss while cutting. In addition, your weight and fat percentage can also give an indication.

8. If there is a threat of loss of muscle mass, it is best to end the cut or take a break (refeed or diet break).

CUTTING VERSUS LOSING WEIGHT

In order to efficiently build muscle mass, you will have to train with a calorie surplus (bulking). For substantial gains, you should go about 10 to 20 percent above your daily maintenance level. Unfortunately, it is inevitable that your fat mass will also increase during bulking. No problem, because you can train off that fat later (by cutting).

Now fat loss in itself is a piece of cake: simply a matter of eating less than you use in energy, or creating an energy deficit. And that in turn is mainly a matter of discipline and self-control.

However, ‘cutting’ is not just about losing your excess pounds. The difference with ‘normal’ weight loss is that with cutting you also have to maintain the muscle mass that you have built up. And preserving muscles in the event of a long-term energy deficit requires smart programming of nutrition, training and recovery.

Beginners can even build muscle with an energy deficit (body recomposition), with average and advanced bodybuilders this is usually not possible and even muscle preservation is already difficult. After all, in the event of an energy deficiency, your body has to use energy sparingly and maintain muscle mass, which consumes energy.

In addition, you should continue to train intensively and voluminously during the cut. This is the only way to give your body the signal that it is ‘necessary’ to leave the existing muscle mass intact. Being able to do heavy strength training with a long-term energy deficit is no easy task. Especially that is what makes cutting so much more difficult than ‘just’ losing weight.

In summary:
Cutting is not ‘just’ losing weight. In addition to losing fat, you have to maintain your muscle mass. Muscle maintenance costs a lot of energy, so your body tends to break down muscle mass in the event of an energy deficit. You can prevent this by keeping training as much as possible as you did in the bulk.

CALCULATING ENERGY BALANCE AND ENERGY DEFICIT

To know whether you have an energy deficit at all or an energy surplus, you need to know your energy balance (also called maintenance level). That is the calorie intake at which you neither gain nor lose weight.

ENERGY BALANCE (MAINTENANCE LEVEL)

Your maintenance level is easy to calculate using an online calculator. However, most of these calculators make a much too rough estimate of the calories you burn with physical activity. Plus, you probably won’t be doing strength training and cardio every day, which is why counting these as part of your maintenance level makes no sense.

We therefore advise you to assume a ‘bare’ maintenance level, in other words your energy needs excluding cardio, strength training and/or other sports. Use our step-by-step plan to accurately calculate your daily calorie requirement.

ENERGY DEFICIT

The energy deficit can be determined in two ways: as a percentage of the weight, or as an absolute value. Usually a percentage is used, because that does the most justice to individual differences. Example: a person with a maintenance level of 2500 kcal per day can eat (2500 – 500 =) 2000 kcal per day with an energy deficit of 20 percent. The absolute energy deficit is therefore 500 kcal.

COUNTING CALORIES

To be sure whether you are actually putting the desired energy deficit into practice, the use of a calorie app is indispensable: a miscalculation of a few hundred calories can already ensure that you no longer have an energy deficit. The macronutrient ratio also plays an important role in the cut, as we will see below. And a calorie app is indispensable for that too.

In summary:
Your energy balance or maintenance level is the number of calories at which you neither gain nor lose weight. Your energy deficit is the amount of calories you eat below your maintenance level, usually expressed as a percentage of your maintenance level. In order to know whether you are actually putting a certain energy deficit into practice, the use of a calorie app is necessary.

CREATING AN ENERGY DEFICIT

It is clear that you need an energy deficit: your body will only use fat reserves when it does not receive enough energy, in other words through your diet. Reducing your fat percentage is theoretically possible without an energy deficit, namely if you build more muscle than you gain fat mass. But for natural bodybuilders, especially the more advanced, this is hardly feasible in practice.

To create an energy deficit you can in fact turn two knobs: that of food (energy coming in) and that of movement (energy that is used). If you had to choose between the two, the first is by far the most effective ^[ i ] : fat loss always starts with a calorie-restricted diet. Think about it: there are many diet methods (keto, paleo, intermittent fasting , high-carb, low-carb), but ultimately they are all based on one thing: an energy deficit.

You can possibly make dieting easier by doing some cardio, but that is not strictly necessary. Of course doing cardio does offer all kinds of health benefits, but we are now focusing purely on body composition. Excessive cardio can have a negative effect on your strength training recovery.

In summary:
You can only lose fat with an energy deficit. A calorie-restricted diet is by far the most effective way to create that deficit (way more efficient than just doing cardio).

SIDE EFFECTS OF AN ENERGY DEFICIT

If you maintain an energy deficit for a longer period of time, this has consequences for the functioning of your body. Yes, you burn fat, but a lot more happens. Your body functions on survival principles and doesn’t care about your aesthetic goals. You will therefore have to deal with the following matters.

YOUR BODY USES ENERGY MORE EFFICIENTLY (METABOLIC ADAPTATION)

Almost immediately after applying an energy deficit, your body adapts to this by using the available energy more efficiently. For example, it will cut down on unconscious movements (NEAT) and on your resting metabolism. We also call this metabolic adaptation. More on that in this article. As a result, your maintenance level gradually decreases.

Over time, that level has even dropped to such an extent that you no longer have an energy deficit, even though you still eat just as little. In short, you end up on a fat loss plateau. In order to burn fat again, you will have to reduce your calorie intake even further, or do (more) cardio.

GLYCOGEN STORES ARE DEPLETED

Glycogen is the energy your body produces from glucose and then stores it in your liver and muscles (this process is called glycogenolysis). The glycogen in your muscle cells is the most important and efficient source of energy for strength training. These stocks are replenished after the training. Complete replenishment of glycogen stores can take up to 24 hours ^[ ii ] . This requires carbohydrates. In total, only about 2 grams of glycogen can be stored per 100 grams of muscle. The glucose that is not used for direct energy or for glycogenolysis is stored as fat.

With an energy deficit you get relatively few carbohydrates. During cutting, your protein intake must remain high (about 1,8 g protein per kg body weight per day), so you have to cut back on carbohydrates and fats. Even if you maintain a minimal fat intake (0.5-1 g per kg body weight per day ^[ xx ] ), you still get fewer carbohydrates than normal. After some time, the glycogen stores in your muscles can no longer be fully replenished, which is at the expense of your energy and therefore your performance during training. In combination with the previous point (metabolic adaptation), this problem only gets worse over time. This threatens to lose muscle mass. In such a case, you’d better take a refeed or diet break (see also below).

HORMONE LEVELS ARE GETTING WORSE

With a long-term energy deficit, the values of important hormones also change. And unfortunately not for the better. For example, the level of leptin, also known as the ‘hunger hormone’ ^[ iii ] decreases . That sends signals to your brain that there is an energy deficit, which increases your feeling of hunger. Leptin also works closely with the thyroid hormones. Reduced leptin levels can therefore also result in an (even) slower metabolism. In addition, they may negatively impact things like libido, overall energy, strength, ability to recover and mood. To prevent too fast letptine drops, you have to keep the proportion of carbohydrates in your daily calorie intake as high as possible.

With a persistent energy deficit, your body will also cut back on the production of testosterone. Rest assured, that does not immediately mean that you will lose muscle mass, because then your testosterone levels should already be below the medical threshold. That doesn’t happen so quickly, not even in the thirties and forties. However, lower testosterone levels also have a negative influence on energy, mood, sexual desire and unfortunately also on the degree of fat burning. To keep your testosterone levels up to some extent, eat at least 0.6 g of fat per kg of body weight every day ^[ xx ] . Make sure you get both saturated and monounsaturated fats ^[ iv ] .

Finally, in the event of an energy deficiency, the value of the ‘stress hormone’ cortisol increases, which has an unfavorable influence on fat burning and can also have a catabolic effect, ie promotes muscle breakdown ^[ v ] . A good night’s sleep is very important to keep cortisol in check . You should also not do excessive cardio, which increases your coristol levels without counteracting increased testosterone levels (as is the case with strength training).

All mentioned factors worsen as an energy deficit persists. It is also known as diet fatigue .

In summary:
The longer an energy deficit lasts, the more burden (‘diet fatigue’) you experience: metabolic adaptation (which causes your maintenance level to fall), glycogen stores that are depleted (which means you have less energy for your training) and hormone levels that deteriorate (which causes your e.g. getting more hungry and less energetic).

INDIVIDUAL DIFFERENCES

As much as we would like to give you ready-made answers, the optimal energy deficit does not exist. How deep you should write in your calories depends on many personal factors. As:

the fat percentage;
the degree of everyday busyness and stress;
the purpose of the cut: complete training/competition preparation or interim fat loss (‘minicut’);
the time limit, if any, to achieve that goal.

In summary:
The optimal energy deficit does not exist, because too many personal factors play a role.

FAT PERCENTAGE AND FAT LOSS

Your current fat percentage largely determines how much weight you can lose in a certain time frame. Take a look at the graph below. If you are above 15%, you can initially lose more than 1% of your weight weekly.

How much weight you can lose with a certain fat percentage. Source: Revive Stronger.

With such a high fat percentage, dietary fatigue occurs much less quickly. After all, the body then has sufficient fat reserves to maintain energy and hormone levels. In addition, the metabolism is in principle high, so that its decline is less noticeable. Keep in mind that it is much easier to go from 18 to 12 percent body fat, for example, than from 12 to 10. With a high fat percentage you can safely handle a large energy deficit, even if you will have it over time, when you still experience dietary fatigue. occurs should be reduced.

In summary:
Your current fat percentage partly determines how much fat you can lose in a certain period of time. People with a high fat percentage can lose fat faster and therefore also have a greater energy deficit.

DANGERS OF AN INCORRECT ENERGY DEFICIT

The question now is how big an energy deficit should be for optimal cutting results. Not an unimportant question, because an incorrectly chosen energy deficit can lead to three problems:

you spend way too long cutting, so you can’t build muscle for a long time;
you lose muscle mass while cutting;
you aren’t able to maintain cutting.

In the worst case, all three problems occur at the same time.

In short, the perfect energy deficit is the energy deficit in which you achieve maximum fat loss with a minimum loss of muscle mass, and that can be sustained physically and mentally.

In summary:
A wrongly chosen energy deficit can, among other things, cause you to cut unnecessarily long or lose muscle mass.

HOW BIG SHOULD THE ENERGY DEFICIT BE?

Which energy deficit is efficient for an average bodybuilder? Let’s go through the options.

SMALL

Most bodybuilders who start cutting already have a fairly low fat percentage, often below 15% (men). The body can then only have few fat reserves, so that diet fatigue will occur fairly quickly. This is reason for many coaches to advise a small energy deficit, for example of only 10% of the maintenance level. In practice, this means that you only eat a few hundred calories less than usual.

However, such a limited energy deficit is far from efficient. After all, it means that you lose fat very slowly and the moment there is any substantial fat loss, diet fatigue still occurs. Suspended execution, as it were.

Of course, a limited energy deficit is the safest route to muscle preservation, but the risk of muscle loss during cutting should not be exaggerated. With sufficient protein intake and effective strength training, your muscle mass should normally be able to remain intact, even with a greater energy deficit ^[ xix ] .

The consequence of such a careful calorie reduction is that you are cutting unnecessarily long, and cutting means that you cannot build muscle mass.

That a small energy deficit is ineffective is illustrated by a 2015 study ^[ vi ] . Finnish scientists examined the differences between managing a small calorie deficit (-12%, av. -300 kcal) and an average deficit (-24%, av. -750 kcal) in strength-oriented athletes (jumpers and sprinters). The athletes with the small calorie reduction had hardly lost any fat after four weeks. Their muscle mass was preserved. In the group with the major deficit, however, they had lost an average of almost 2 kg: largely fat, because the muscle mass was also virtually unaffected. Important: protein intake was maintained in both groups.

BIG

However, that does not mean that you can radically cut your calories. And for three reasons:

On balance, a normal person needs 1200-1600 kcal per day to function properly ^[ vii ] ;
There is a limit to how much fat you can burn daily without also losing muscle mass ^[ viii ] . We already saw that that limit depends on your fat percentage.
Several studies have made it plausible that a large energy deficit can more easily be at the expense of muscle mass ^[ ix ]^[ x ]^[ xi ]^[ xii ] . Although you lose weight faster with a large energy deficit, the fat loss is offset by a greater loss of muscle mass than if you would lose weight more slowly.

Now, even with a smaller energy deficit, you will sooner or later have to deal with reduced training performance due to faster depleted glycogen stores and an increase in cortisol. But with a large energy deficit, this seems to occur relatively faster, according to the studies, with a relatively faster loss of muscle mass as a possible result. In fact, this is also apparent from a 2018 meta-analysis, which looked at 16 studies examining the effects of energy shortages of varying magnitude ^[ xiii ] . This showed that a deficiency greater than 300 kcal resulted in a significant decrease in physical strength ^[ xiv ]. It should be noted, however, that these were studies that examined the physical performance of soldiers and not specifically that of strength athletes.

AVERAGE

So there actually seems to be a ‘sweet spot’ for fat loss, an energy deficit where you lose fat the fastest without losing muscle mass. Based on the available research, coach and scientist Eric Helms made the following recommendation in 2014:

Caloric intake should be set at a level that results in bodyweight losses of approximately 0.5 to 1%/wk to maximize muscle retention. ^[ xv ]

If you translate that into an energy deficit, you arrive at 20-25% of your maintenance level, according to Helms, an average energy deficit. At a maintenance level of 2500 kcal per day, you should therefore have a deficit of 500-600 kcal. A larger energy deficit (30%) is only suitable for people who are very overweight (fat percentage > 15%) or possibly in the case of a ‘minicut’ of a few weeks at most (see below).

Keep in mind that you need to reduce your calorie intake over time to maintain that deficit. This is under the influence of the aforementioned metabolic adaptation, whereby the maintenance level decreases and at a certain point you no longer have an energy deficit.

There is no guideline for the extent to which the maintenance level decreases for the given energy deficit. That’s mostly a matter of keeping an eye on the scales: if you lose less than 0.5 kg per week over time, you’ll need to lower your calorie intake to keep losing fat at the same rate. Or you have to do (more) cardio.

In summary:
On average, with an energy deficit of 20-25% you realize the most fat loss while retaining muscle mass. With this deficiency you will lose 0.5 to 1% of your body weight weekly. To maintain this rate of fat loss and prevent a plateau, you will need to lower your maintenance level over time. This can be done by eating less and/or by doing (more) cardio.

THE MACROS: CARBOHYDRATES HIGH!

In addition to calorie intake, the distribution of those calories among the macronutrients (proteins, carbohydrates and fat) also plays an important role in cutting.

In essence: keep your protein intake high during the cut, but don’t go higher than necessary (1.8-2.7 g/kg/day) and do not eat more fat than is strictly necessary (~0.6 g/kg/day) So the rest of your calories can go to carbohydrates, the primary energy source for strength training. In short:

proteins: 1.8-2.7 g per kg of body weight
fats: 0.5-1 g per kg of body weight
carbohydrates: the rest

But carbohydrates are fattening, right? No, calories are fattening. Or rather, too many calories. For fat loss, it makes no difference whether you go low-carb or low-fat, as a large-scale study has shown ^[ xviii ] .

In summary:
Keep your protein intake high during the cut, but don’t go higher than necessary (~1.8-2.7 g/kg/day) and do not eat more fat than is strictly necessary (0.5-1 g/kg/day), so the rest of your calories can go to carbohydrates, the primary energy source for strength training.

HOW DO YOU KNOW IF YOU ARE LOSING MUSCLE MASS?

If you follow the rules of cutting and use a calorie app to monitor your diet, you don’t have to worry about muscle loss. However, loss of muscle mass cannot be completely ruled out, especially not with a prolonged cut or if you (forced) use an aggressive energy deficit. But how do you actually know if you are losing muscle mass?

MIRROR

Of course there is the mirror, but it can be a deceptive indicator. With an energy deficit, your muscles will quickly look less full – flatter, and smaller. However, this is probably not a result of muscle loss, but of the less full glycogen stores in your muscles, which in turn are the result of the reduced carbohydrate intake. So don’t panic.

You will only see the true result of your cut much later, when you eat ‘normally’ again and consume a lot of carbohydrates. You have to take into account the fact that you look a little less full during cutting. Even though we can imagine that it is not really motivating.

POWER

The best way to determine whether you’re actually losing muscle mass is based on your performance in the gym (like you keep track of it in training logs).

Normally you should not or hardly lose any strength during a cut, except if you cut for a long time or if you cut with a very low fat percentage. If you lose significant strength on the important exercises, that is probably an indication of (beginning) muscle loss.

Keep in mind that the relationship between muscle size and strength is not a completely one-to-one. For example, we know from anecdotal evidence that you often become less strong if you have less fat on your bones.

Can you also get stronger during the cut? In theory yes. That would mean that you build muscle mass, despite having a calorie deficit, so body recomposition. In practice, this usually only happens with novice strength athletes and/or with people who have a lot of fat mass. If it works, you can see body recomposition as a very successful cut.

WEIGHT AND FAT PERCENTAGE

Keep a close eye on the scale. If you lose more than 1% of your body weight weekly with an energy deficit of 20-25%, this may mean that you are losing muscle mass in addition to fat.

Keep in mind that you may lose much more than 1% in the first week of the cut. However, this is due to the loss of fluids due to less food volume in your entire body. After this fluid loss, your weight loss should stabilize at 0.5 to 1% per week. Weigh yourself in the morning, right after getting up. Compare the results from week to week.

An even more reliable indicator is the decrease in your weight in relation to that of your fat percentage. However, fat percentage is difficult to measure accurately yourself .

WHAT TO DO IN CASE OF MUSCLE LOSS?

If you think you are losing muscle mass, you need to intervene. Maybe it’s time to ‘just’ end your cut and start bulking again. Cut cycles don’t have to be very long anyway. So-called minicuts are an effective means of keeping the fat percentage in check during the ‘bulk season’. A minicut usually refers to a cutting cycle of two to a maximum of six weeks.

If stopping is not an option, for example because you are working towards a competition, photo shoot or vacation, then hopefully you have scheduled enough time to insert a refeed (short break) or diet break (long break). Learn how to apply these strategies in this article. It also includes strategies for when you don’t have time for a break.

In summary:
Your strength performance during training is the most important indicator of possible muscle loss. In addition, your weight and fat percentage can also give an indication. In case of (imminent) muscle loss, it is best to end your cut or take a break.

IN SUMMARY