Gaining Muscle Mass in a Deficit vs. Bulking (Research Review)

Written by: Adam Tzur
Acknowledgements: Brandon Roberts
Article length: ~3200 words
Last updated: 25.04.2018
Studies reviewed: 60+



  • Beginners and people with relatively high body fat percentages can gain muscle mass & strength in a calorie deficit (also known as a cut or fat loss program).
  • A dirty bulk might lead to quicker muscle gains but also greater fat gains.
  • Intermediately trained lifters might be able to gain in a deficit, as well. If your body fat is low and you are well trained, it’s safer to go for a slow/lean bulk.
  • Studies suggest that it's harder to gain muscle mass compared to strength in a deficit, if you’re trained. But, you might be able to do both depending on the factors listed in this article.
  • Here is an overview of the deficit gaining and body recomposition studies


  • Untrained = Someone who is new to lifting. A beginner.
  • Trained = These are intermediately trained lifters. Usually, they will have 2+ years of experience with strength training.
  • Advanced = These are typically athletes or bodybuilders. They are very strong in relation to their body weight, and usually have considerable amounts of lean mass (i.e. rugby players). Or, they could be bodybuilders with a lot of lean mass and low body fat %.

The article continues below

Can we gain muscle in a deficit?

The preponderance of the evidence suggests that both beginners, novices, intermediates, and even advanced athletes can gain muscle and strength while losing fat. You can find an overview of the deficit gaining and body recomposition studies further down in the article.

Things to keep in mind:

  1. We might lose muscle mass if we cut calories without doing strength training (Villareal et al., 2016). Hence, it’s important to do strength training while cutting to avoid muscle loss (Stiegler and Cunliffe 2006; Miller et al., 2013; Churchward-Venne et al., 2013; Trexler et al., 2014; Helms et al., 2014a; Helms et al., 2014b; Murphy et al., 2014; Hulmi et al., 2016). But in older adults, aerobic training in itself could preserve more muscle mass than being sedentary (Weinheimer et al., 2010).
  2. Cutting should be done with small or moderate deficits (i.e. around -500 kcal) to avoid loss of muscle mass (Garthe et al., 2011; Sundgot-Borgen and Garthe, 2011; Trexler et al., 2014; Helms et al., 2014a; Murphy et al., 2014; Khodaee et al., 2015; Manore et al., 2015; Hulmi et al., 2016). Very low calorie diets might lead to more muscle atrophy (Chaston et al., 2007).
  3. There are other negative effects of rapid weight loss (hormonal, physiological, and psychological) (Sundgot-Borgen and Garthe, 2011; Franchini et al., 2012; Trexler et al., 2014; Khodaee et al., 2015; Manore et al., 2015; Hulmi et al., 2016; Aloui et al., 2016; Hulmi et al., 2016). I will review this in more detail in another article.
  4. You might want to eat a high-protein diet when you go on a cut to preserve muscle mass (Stiegler and Cunliffe 2006; Wycherley et al., 2012; Churchward-Venne et al., 2013; Pasiakos et al., 2013; Phillips, 2014; Trexler et al., 2014; Helms et al., 2014; Helms et al., 2014a; Murphy et al., 2014; Manore et al., 2015; Kim et al., 2016; Hulmi et al., 2016).
    For example, 1.5-1.8 grams protein per kg bw (Phillips, 2014; Murphy et al., 2014; Hulmi et al., 2016). Maybe even more (i.e. >2 grams per kg bw) (Phillips, 2014; Murphy et al., 2014; Helms et al., 2014).

“While greater deficits yield faster weight loss, the percentage of weight loss coming from lean body mass (LBM) tends to increase as the size of the deficit increases ”

- Helms et al., 2014a

Deficit gaining, recomping, or bulking?

We are similar, yet different

Athletes have different levels of success when bulking, as shown in the graph below. The same is true for cutting (Garthe et al., 2011). Not everyone can gain muscle and lose fat at the same time. It might depend on factors like:

Garthe et al., 2012 - Athletes respond differently to bulking.

A great deal of studies show that there are high-responders, low-responders, and non-responders to training. This means that our bodies react differently to similar training programs and diets. I won’t go into details here, but check out my article on it, and Greg’s, as well.

Cutting with little body fat

You might be more likely to lose muscle mass if you cut calories when your body fat is already low (i.e. below 7-10% for men) (Rossow et al., 2013; Helms et al., 2014a; Kistler et al., 2014; Huovinen et al., 2015; Robinson et al., 2015). In two studies on women bodybuilding competitors, they lost fat and muscle mass during contest prep but it was probably because they hit 12% body fat by the end (van der Ploeg et al., 2001; Hulmi et al., 2016). This is very low for women! To illustrate it, women suffering from anorexia nervosa have 9-13% body fat (Mayo-Smith, 1989; Mayer et al., 2005). The menstrual cycle can stop when body fat becomes very low (Halliday et al., 2016). Some suggest 12% for women is akin to 4% for men. Here’s a comparison image from Builtlean:

I don’t want to encourage you to drop to unhealthy bodyfat levels that are akin to eating disorders. So please consider your level of body fat before you decide to restrict calories. Drastic calorie reductions might lead to disordered eating (Manore et al., 2015). Although, this shouldn’t be a problem for most of us since we’re more likely to have too much body fat rather than too little.

What is the best method to gain muscle and lose fat?


“The best method” depends on your diet and program (Helms et al., 2014b). As we see in the graph below, some women were able to gain lean mass, but most did not (though they did go to very low body fat levels, which affects gains!). They all used their own diets and training programs.

Figure by Hulmi et al., 2016

With that caveat out of the way, let’s see what the research has to say.


Bulking (eating in a surplus) is the traditional way of gaining muscle mass. You can gain slowly (lean bulk) or quickly (dirty bulk). It’s sometimes said that a dirty bulk is better for putting on muscle mass, but you will also gain a lot of fat at the same time (Garthe et al., 2012). In the figure below, the dirty bulk group gained a lot more fat than the lean bulk group.

“The excess energy intake in a weight gain protocol should (...) be considered carefully since greater rates of gain are likely to include larger increases in body fat storage in already strength-trained athletes” - Garthe et al., 2012

Bar chart by Garthe et al., 2012 (Edited for clarity) - The white group (NCG) ate ~3600kcal, black group ate ~3000kcal

Some have pointed out that the amount of energy you consume affects how much muscle you can build:

“a significant correlation between total energy intake and gains in lean mass (r = .43, p = .04) was demonstrated” - MacKenzie-Shalders et al., 2016

Others support this idea as well, the more energy and protein you consume, the more gains. From a metabolic ward study:

Figure by Bray et al., 2012 - Note that the participants were in a metabolic ward and they did not strength train during the intervention and still gained LBM. High and medium protein groups increased their energy expenditure by about 200 kcal by the end of the study

Though if you don’t consume enough protein, the extra energy is stored as fat, as you can see in the low-protein group (same study):

Bar chart by Churchward-Venne et al., 2013, based on Bray et al., 2012. This shows us that it’s necessary to consume enough protein if we want to gain LBM.

"With the low protein diet, more than 90% of the extra energy was stored as fat. Because there was no change in lean body mass" - Bray et al., 2012

In conclusion for bulking, there's some evidence that more calories might lead to greater LBM gains, but the evidence isn't very strong and we need more studies.

Gaining in a caloric deficit

It is possible to gain muscle mass and strength in a caloric deficit, but there are many factors that decide whether it will work for you or not. It’s probably a good idea to go for deficit gaining if you’re overweight, or a beginner/novice. If you’re both, even better.

If you are, however, a lean athlete with years of strength training experience, it might work, it might not. I can’t speak in certainties. You could try it, just make sure to keep protein high (i.e. 2g per kg bw), go for a slow cut (maximum -500kcal per day), get enough sleep & recovery, avoid excessive stress, have the right genetics, and use a solid strength training program. The better your body composition is, the harder deficit gaining will be for you, in all likelihood (Helms et al., 2014b; Rossow et al., 2013; Kistler et al., 2014; Huovinen et al., 2015). The graph below shows that endurance athletes with lower body fat %, lost FFM on a cut. Those with body fat over 10% did not.

Correlation by Huovinen et al., 2015. Note that they didn’t follow a strength training program in this study and that the sample size was small.

Gaining strength is easier, because more studies suggest that you can gain strength even if you’re quite well trained (see the study overview table above for details).

Bar chart by Garthe et al., 2011 - Novice/intermediate lifters gain more strength on the BP during a slow cut (SR) compared to a quick cut (FR).

Overview of Studies

There are several studies that suggest beginners and novice/intermediate lifters can gain muscle and strength while losing fat.  Note that we've excluded several studies from this table. For example, studies with unhealthy subjects, low protein intakes, and some studies where participants didn’t strength train. I do this because it’s normal to lose muscle mass when subjects don’t lift or eat enough protein.

Note: there's also a substantial amount of studies where subjects lose both fat mass and lean body mass. These studies will be included in a forthcoming article.

Body Recomposition and Deficit Gaining


Study & Subjects Results
Sigal et al., 2014
N = 304
Duration: 22 weeks
Diet: not controlled
Untrained 14-80 y.o. boys and girls
Not measured

Fat mass


Treuth et al., 1994

N = 22
Duration: 16 weeks
Untrained 60 y.o. men

+2 kg fat-free mass

Fat mass
-2 kg fat mass


Donnelly et al., 1993

N = 14
Duration: 13 weeks
Untrained obese women
800 kcal diet (VLED)

16 kg weight lost

24% weight lost was from FFM (glycogen/water mass loss?)
Gain in muscle fiber CSA

Fat mass
76% weight lost was from fat

Demling and DeSanti, 2000

N = 38
Duration: 12 weeks
Untrained 34 y.o. overweight men

Strength training groups gained 2 and 4 kg FFM

Fat mass
Mean fat loss 2.5 to 7 kg over 3 different groups

Strength increased 29% and 59%

Arazi and Asadi, 2011

N = 39
Duration: 1 + 8 weeks
Untrained 20 y.o. men

Increased arm circumference

Fat mass


Nindl et al., 2000

N = 31
Duration: 24 weeks
Untrained 28 y.o. women

2.2% increased LBM
Increased rectus femoris CSA and total thigh CSA

Fat mass
10% decreased fat mass

Palumbo et al., 2017

N = 16
Duration: 12 weeks
Untrained ~31yo women

Total body mass unchanged (recomposition)

Gained ~1.2 kg LBM (DXA). LBM gains were only significant to the limbs they were training (upper-body group vs lower-body group)

Fat mass
Lost ~1.7 to ~2 kg fat

Josse et al., 2010
N = 20
Duration: 12 weeks
Untrained 23yo women
BMI = 25-26
~2 kg gain in LBM

Fat mass
Lost 1.6kg fat

Strength increased in all exercises by 52103%

Consolazio et al., 1975

N = ?
Duration: ~6 weeks
Untrained men

Protein group gained 3.28 % LBM

Fat mass
Protein group lost 2.21 kg fat mass

Eliot et al., 2008

N = 42
Duration: 14 weeks

Untrained 48–72yo men

Whey Protein group increased arm bone-free FFM by 8.2% (*), and whole-body BF-FFM by 0.7 kg (non-significant)

Fat mass
Fat mass was completely unchanged (0 kg).
Body recomposition

Verreijen et al., 2017
N = 100
Duration: 10 weeks
Untrained 55–80 yo obese men
Results for PRO+EX group

Gained 0.5kg LBM

Fat mass
Lost 3kg fat mass

Meirelles and Gomes, 2016

N = 21
Duration: 8 weeks
Beginners, 34–45 yo overweight and obese men and women

Body recomposition

Maintained muscle thickness

Fat mass
Body fat decreased 35%, waist circumference decreased by ~4 cm

1419% increase in strength

Marks et al., 1995

N = 44
Duration: 20 weeks
Inactive, overweight 20–49 yo women

Body mass loss for intervention groups was between -3.7 to -5.4 kg

All groups maintained FFM

Strength 1RM increased significantly for both groups.



Measuring FFM with DXA is imperfect, but not useless

DXA and FFM measurements are imperfect (also read the section below: Glycogen/water mass can affect beginner gains).

For trained athletes, SEM is a couple of % for fat, and around 1% for FFM, according to Garthe et al., 2012 and their repeated DXA measure tests.

“For DXA reproducibility, 10 male and female athletes did two repeated measurements within 24 hours, and the coefficient of variation in DXA Lunar Prodigy total body scan for repeated measurements was 3% for FM and 0.7% for LBM.” - Garthe et al., 2012

Others find little difference between DXA and MRI measurements:

“Dual-energy X-ray absorptiometry and magnetic resonance imaging fat mass measurements showed good agreement (r = 0. 72-0.92); their lean mass measurements were similar as well, showing approximately 5.5% increases in leg lean tissue.” - Nindl et al., 2000

This is just a snapshot from two studies. I will have to write a separate article on body composition measurements, and look at the literature in its totality.

Glycogen/water mass can affect beginner gains

Beginners gain glycogen and water mass when they first start strength training programs. I've previously written about this here. This is a bit of an issue since "noob gains" are partially glycogen/water gains (Ribero et al., 2014). This affects lean body mass (LBM), fat free mass (FFM), or cross-sectional area (CSA). Muscle glycogen/water content even affects MRI measurements (Nygren et al., 2001). But, there are several studies that show beginners lose or maintain FFM when they go on a cut. Probably due to a reduction in carb (glycogen) or protein intake. Hence, it’s not a given that beginners will increase FFM when they train and cut.

In trained lifters, it is unlikely that FFM increases are glycogen/water mass. Here’s why:

  • Trained lifters already had their "noob gains" for glycogen/water mass. These water gains come relatively quickly when we first start to train (Ribero et al., 2014).
  • In a deficit, we eat less carbohydrates. Carb intake regulates muscle glycogen stores. If anything, glycogen stores will shrink slightly in a deficit.

Comparing gains/fat loss across studies with different methodologies is difficult

There are few studies that directly compare bulk/cut vs. recomp vs. deficit gaining

Other considerations

  • Several of the studies have deficit gaining as a secondary outcome (i.e. they're testing other things in the study, while the deficit gaining is more of a side-effect)
  • Fitness research is based on probabilities and averages. Some people might be able to gain in a deficit, some may not be. Many factors affect whether you will be able to successfully gain in a deficit.
  • Survivor bias: Several of the studies had many dropouts. This means that only those that “survived” the study, are measured and evaluated. Those that had no improvements might have become frustrated and dropped out. This could inflate the study results (muscle gain/fat loss).
  • In some studies, i.e. Ploeg et al., 2001, the women who were preparing for a bodybuilding contest did excessive cardio (10h per week), for part of their prep period. They lost FFM, but they might have been able to avoid that if they didn’t do so much cardio (interference effect) (Helms et al., 2014b). They also dropped down to very low body fat levels.

For more info on limitations, read the following article: Why study results don’t always apply to you (the limitations of research)