If you train hard but eat as if you were sedentary, you may be under-fueling without realizing it. The commonly cited recommendation of 0.8 grams of protein per kilogram of body weight per day was originally established to prevent deficiency in the general population. It was not designed to optimize muscle growth, recovery, metabolic resilience, or performance. In practical terms, it represents a minimum threshold for health maintenance, not necessarily a functional target for someone who lifts, runs, or diets.
When researchers began examining protein needs in resistance-trained individuals, the picture became more nuanced. A widely cited meta-analysis by Morton et al. in the British Journal of Sports Medicine (2018) suggests that intakes around 1.4 to 1.6 g/kg/day appear to maximize gains in lean mass for those engaged in strength training, with diminishing returns beyond that range. That does not mean higher intakes are harmful, only that additional benefit becomes less clear. In periods of energy restriction, such as during fat loss phases, protein needs seem to rise. Helms et al. in the Journal of the International Society of Sports Nutrition (2014) observed that higher intakes help preserve lean mass in active individuals dieting aggressively, and more recent analyses tend to support similar ranges. Age adds another layer. Bauer et al. in the Journal of the American Medical Directors Association (2013), along with subsequent reviews in Frontiers in Nutrition, suggest that older adults may require closer to 1.2 to 1.5 g/kg/day to counteract anabolic resistance and reduce the risk of sarcopenia.
Daily totals, however, are only part of the equation. Distribution across meals appears to matter more than many people assume. Research on muscle protein synthesis indicates that while overall intake is the dominant factor, consuming sufficient protein per meal may enhance the anabolic response. Estimates often fall around 0.3 to 0.4 g/kg per meal for younger adults, and somewhat higher for older adults, based on work by Moore et al. in the Journal of Applied Physiology (2009) and later discussion by Schoenfeld and Aragon in JISSN (2018). Eating 10 or 15 grams at a time, even if repeated throughout the day, may not consistently reach the leucine threshold required to effectively stimulate muscle protein synthesis. This detail is frequently overlooked in practice.
None of this suggests that more protein is always better. Excessive intake beyond physiological demand does not guarantee better outcomes and may simply displace other nutrients. Still, equating the minimum requirement with an optimal target can be misleading. If you are physically active, trying to lose fat, or moving into middle age and beyond, relying strictly on 0.8 g/kg may leave adaptation on the table. A range of 1.2 to 1.6 g/kg/day, adjusted for context and distributed thoughtfully across meals, appears to align more closely with current evidence. The key is matching intake to demand rather than defaulting to a deficiency-prevention guideline.
Scientific references
Morton RW et al., 2018, British Journal of Sports Medicine
Helms ER et al., 2014, Journal of the International Society of Sports Nutrition
Bauer J et al., 2013, Journal of the American Medical Directors Association
Moore DR et al., 2009, Journal of Applied Physiology
Schoenfeld BJ & Aragon AA, 2018, Journal of the International Society of Sports Nutrition