Research

Energy balance

The exact energy cost of skeletal muscle hypertrophy is unknown, and common textbook estimates based solely on tissue composition are likely inaccurate because they ignore the metabolic costs of synthesis, exercise, and adaptive thermogenesis.

Do not rely on textbook calculations for the exact energy cost of muscle gain. These estimates are likely inaccurate. Instead, use a conservative surplus (1,500-2,000 kJ/day) and adjust based on your progress. Individual responses vary greatly due to genetics and metabolic adaptations.

StrongRefutesHIGH confidence
The exact energy cost of skeletal muscle hypertrophy is not known. Likewise, it is not clear if this energy cost can be met purely from endogenous (i.e., internal fat stores) and/or exogenous sources (i.e., diet).
Gary Slater et al. · Frontiers in Nutrition · 2019

Why this rating

The paper is a review highlighting the lack of direct research, so the evidence is for the *absence* of precise data.

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

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