Calorie surplus

A calorie surplus is an intake of calories above what the body burns, creating positive energy balance and weight gain.^{1International Personal Trainer Academy, Certified Personal Trainer Textbook, p. 464.} With adequate protein, a surplus favors tissue growth, and resistance training increases that effect.^{2Schoenfeld, Science and Development of Muscle Hypertrophy, 2nd ed., p. 221.} Training status affects where the weight goes: untrained clients gain mostly fat-free mass, while well-trained clients direct more of the surplus toward fat.^{2Schoenfeld, Science and Development of Muscle Hypertrophy, 2nd ed., p. 221.}

Muscle is about 75% water, and a pound contains only 500 to 600 kcal.^{3Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 131.} Building it costs more: tissue synthesis, training and adaptive increases in expenditure all need fuel.^{3Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 131.}

Where sources differ

The NSCA suggests 350 to 500 kcal a day above maintenance calories to support about a pound of lean gain per week, with smaller surpluses for experienced clients.^{3Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 131.} Schoenfeld cites 500 to 1,000 kcal a day for well-trained clients, or 200 to 300 for those who want to limit fat gain.^{2Schoenfeld, Science and Development of Muscle Hypertrophy, 2nd ed., p. 221.} Helms sets lower targets scaled to body weight and training experience.^{4Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 67.}

In practice

• Helms targets monthly gains of 1 to 1.5% of body weight for beginners, 0.5 to 1% for intermediates and up to 0.5% for advanced clients.^{5Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 61.} For a 180 lb (82 kg) beginner, that’s about 200 to 300 kcal a day over maintenance.^{4Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 67.}
• Faster gains mostly add fat: in a 12-week study of trained athletes, a small surplus built the same muscle and strength as an extra 600 calories a day, with one fifth of the fat gain.^{6Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 60.}
• Keep protein at 1.6 g/kg of body weight a day or more.^{3Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 131.}