It's advantageous to be in a caloric surplus to gain muscle, but bodybuilders should strategically monitor their surplus so they don't gain excess body fat.


  • ·      Much of the research has shown that caloric surplus to gain muscle of 500 calories per day result in a large surplus of fat gain
  • ·      A smaller calorie surplus for muscle growth is recommended for advanced bodybuilders if trying to minimize fat gains (200-300 kcals)


Bulking up is the time to put on strength and size, but the problem is that this often occurs with large increases in fat mass. Researchers had subjects perform a 6-week supervised resistance training protocol 3 sessions per week. The resistance training protocol was periodized to vary the exercise intensity through the training based on repetitions in reserve (RIR). Weeks 1 and 4 had training intensity of 2 RIR, Weeks 2 and 5 were at 1 RIR, and Weeks 3 and 6 were set at an intensity of 0 RIR.

The subjects in the study were encouraged to gain 1 pound or .45 kg per week and were weighed before each training session to promote compliance and encourage weight gain. The subjects drank a mass gainer that was 647.5 calories each day (i.e., 5.5 g fat, 123.5 g carbohydrate, 26 g protein).

At the end of the study, the subjects’ strength and lean mass all went up. Their leg press 1RM increased by 37.2%, bench press 1RM by 12.5%, quad thickness increased by 7.4%, and biceps thickness by 4%. These are great gains, but now for the bad news. The subjects gained three times as much fat mass as lean mass gains (12%). This suggests that gaining 1 pound a week to increase muscle mass results in excess fat gain. Lifters concerned about minimizing fat mass should consume a much lower caloric surplus to minimize fat gains. (12)


Look in any health food store; you will see “MASS GAINERS” anywhere from 1000 to 5000 calories per serving. If you are old enough, you can remember that these weight gainers came in what appeared to be 10 lb. dog bags, and some came in giant cement buckets. Many lifters often consume excess calories during a bulking phase or a mass-gaining phase. So how many extra calories does it take to build muscle?


An energy deficit is never anabolic. It’s always easier to gain muscle in a calorie surplus. People who have never trained before can start a training program and gain muscle in a calorie deficit. (1) This is often seen in obese patients who lose body fat while gaining muscle in a calorie deficit. (2) Advanced athletes will need fewer calories to gain lean mass without the risk of gaining excess body fat.

Overfeeding has been well documented to increase both lean mass and fat gains. The response is variable among individuals. It has been found that 100 days of energy surplus (1000 calories per day) among young, lean male identical twins resulted in a significant individual change in body composition. The average weight gain was about 18 pounds, but the weight gain ranged from 9.46 pounds to 29.26 pounds. For every 2 kg (1.1 pound) of fat mass gained, there was 1 kg (.5 pounds)of lean mass gained. (3) The most common recommendation in nutrition textbooks is to consume a 400-500 calorie surplus per day to increase muscle mass.

The energy content of muscle is estimated to contain approximately 700 to 800 kcal per pound (454 g) due to its high water content (~ 70% water, ~ 22% protein). These estimations have been further improved by Slater et al. in which it was calculated that skeletal muscle contains (543 to 565 kcal/lb.; 370 kcal from protein, 152–164 kcal from fat, and 32–50 kcal from glycogen). (4)  Thus, a weekly surplus of 330-500 calories would result in additional increases in lean mass; however, this has not been scientifically validated. (5)

what is bulking calorie surplus how many calories to gain muscle but not fat how much of a calorie surplus to gain muscle how many extra calories to gain muscle how many calories should i eat to gain lean muscle do you need a calorie surplus to gain


Much of the research has shown that 500 calories per day can lead to additional gains in body fat. Garthe et al. found that athletes consuming 500 calories extra a day had a 15% increase in fat mass compared to a moderate surplus diet, yet lean mass gains were similar. The authors suggested a 200-300 kcal surplus may be more appropriate for increasing lean mass while minimizing fat mass.(6)

Similar results were demonstrated when subjects consuming a high-calorie diet (4000 calories daily) gained more muscle and fat than a moderately high-calorie diet (2500 calories daily).(7) Thus, the moderate surplus group gained a lean mass: fat mass of a 4:1 ratio, and the high-calorie surplus group gained lean: fat mass at a 4:3 ratio. Kreider et al. found that taking a 1000 kcal shake per day led to similar increases in lean mass as a carbohydrate drink but greater gains in fat mass.(8)

what is bulking calorie surplus how many calories to gain muscle but not fat how much of a calorie surplus to gain muscle how many extra calories to gain muscle how many calories should i eat to gain lean muscle do you need a calorie surplus to gain


The research suggests that excess calories greater than 500 calories per day can lead to greater increases in lean mass but also fat mass. If you are looking to minimize gains in fat mass, it’s recommended that you start will smaller calorie surpluses (i.e., 200-300 calories) and then add more calories if needed. The simple answer is that scientists don’t know the exact calories to recommend for increasing lean muscle mass while minimizing fat mass gains.

If you want to gain muscle and fat, then the mega mass shakes are perfectly fine, but it’s become clear that you don’t need 1000 calorie shakes per day as once thought. You should increase your protein intake to minimize the fat gain when using a calorie surplus for muscle growth.


The studies by Antonio et al. on protein overfeeding suggest that excess protein will not contribute to excess fat gain.(9,10) It should be mentioned that an earlier study in experienced lifters who were in caloric maintenance were able to gain muscle (~2.2 lbs.) with protein intakes greater than 2.1 g/kg/bw (close to 1 gram of protein per pound of body weight) in a 10-week study. Interestingly, the control group that consumed similar calories but had less protein (1.6 g/kg/day) gained no lean mass during the 10 weeks.(11) In sum, it’s advantageous to be in a calorie surplus for muscle growth, but bodybuilders should strategically monitor their surplus, so they don’t gain excess body fat.

A meta-analysis of all the studies examining calorie deficits and changes in lean muscle mass responses were examined. The authors found that an energy deficit of 500 calories resulted in blunted increases in lean muscle mass. If you are trying to gain muscle, it’s always better to be in a caloric surplus. (13)

Calorie Surplus for Muscle Growth Key Points

  • ·      Much of the research has shown that 500 calories per day result in a large surplus of fat gain.
  • ·      A smaller calorie surplus for muscle growth is recommended for advanced bodybuilders if trying to minimize fat gains (200-300 kcals)


1.    Longland TM, Oikawa SY, Mitchell CJ, Devries MC, Phillips SM. 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. Am J Clin Nutr 2016; 103(3): 738-46.

2.   Donnelly JE, Sharp T, Houmard J, et al. Muscle hypertrophy with large-scale weight loss and resistance training. Am J Clin Nutr 1993; 58(4): 561-5.

3.  Bouchard C, Tremblay A, Després JP, et al. The response to long-term overfeeding in identical twins. N Engl J Med 1990; 322(21): 1477-82.

4.  Slater GJ, Dieter BP, Marsh DJ, Helms ER, Shaw G, Iraki J. Is an Energy Surplus Required to Maximize Skeletal Muscle Hypertrophy Associated With Resistance Training. Frontiers in Nutrition 2019; 6.

5.         Larson-Meyer DE, Krason RK, Meyer LM. Weight Gain Recommendations for Athletes and Military Personnel: a Critical Review of the Evidence. Current Nutrition Reports 2022.

6.         Garthe I, Raastad T, Refsnes PE, Sundgot-Borgen J. Effect of nutritional intervention on body composition and performance in elite athletes. European Journal of Sport Science 2013; 13(3): 295-303.


7.         Ribeiro AS, Nunes JP, Schoenfeld BJ, Aguiar AF, Cyrino ES. Effects of Different Dietary Energy Intake Following Resistance Training on Muscle Mass and Body Fat in Bodybuilders: A Pilot Study. J Hum Kinet 2019; 70: 125-34.

8.         Kreider RB, Klesges R, Harmon K, et al. Effects of Ingesting Supplements Designed to Promote Lean Tissue Accretion on Body Composition during Resistance Training. International Journal of Sport Nutrition 1996; 6(3): 234-46.

9.         Antonio J, Ellerbroek A, Silver T, et al. A high protein diet (3.4 g/kg/d) combined with a heavy resistance training program improves body composition in healthy trained men and women – a follow-up investigation. Journal of the International Society of Sports Nutrition 2015; 12(1).

10.       Antonio J, Peacock CA, Ellerbroek A, Fromhoff B, Silver T. The effects of consuming a high protein diet (4.4 g/kg/d) on body composition in resistance-trained individuals. Journal of the International Society of Sports Nutrition 2014; 11(1): 19.

11.       Kerksick C, Rasmussen C, Lancaster S, et al. The Effects of Protein and Amino Acid Supplementation on Performance and Training Adaptations During Ten Weeks of Resistance Training. Journal of strength and conditioning research / National Strength & Conditioning Association 2006; 20: 643-53.

12. Smith, R.W.; Harty, P.S.; Stratton, M.T.; Rafi, Z.; Rodriguez, C.; Dellinger, J.R.; Benavides, M.L.; Johnson, B.A.; White, S.J.; Williams, A.D.; Tinsley, G.M. Predicting Adaptations to Resistance Training Plus Overfeeding Using Bayesian Regression: A Preliminary Investigation. J. Funct. Morphol. Kinesiol. 2021, 6, 36.


13. Murphy, C., & Koehler, K. (2022). Energy deficiency impairs resistance training gains in lean mass but not strength: A meta-analysis and meta-regression. Scandinavian journal of medicine & science in sports, 32(1), 125–137.

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