Research

Energy balance

Skeletal muscle hypertrophy can occur in an energy deficit, particularly in resistance training-naive, overweight, or obese individuals, challenging the textbook requirement for an energy surplus.

If you are new to resistance training or have higher body fat, you do not need to eat in a caloric surplus to build muscle. You can build muscle while losing fat by focusing on high protein intake and consistent resistance training. If you are already highly trained and lean, a small surplus may be more beneficial, but it is not strictly required for all populations.

GoodRefutesHIGH confidence
Indeed, there is clear evidence of marked skeletal muscle hypertrophy in response to a novel resistance training stimulus in otherwise healthy, overweight individuals in conjunction with a hypoenergetic, higher protein meal plan (33, 34).
Gary Slater et al. · Frontiers in Nutrition · 2019

Why this rating

Supported by multiple cited studies showing hypertrophy in deficits, though the paper notes this is less evident in highly trained individuals.

Source

Is an Energy Surplus Required to Maximize Skeletal Muscle Hypertrophy Associated With Resistance Training

Gary Slater et al. · Frontiers in Nutrition · 2019

DOI 10.3389/fnut.2019.00131

narrative_reviewCited 81×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →