The fitness industry’s unwavering commitment to the 30-gram protein-per-meal threshold may rest on shakier scientific ground than widely assumed. A landmark 2009 study by Moore and colleagues—conducted with just 6 subjects and measuring muscle protein synthesis over only 4 hours—became the foundation for a claim that persisted largely unchallenged for over a decade.
Recent peer-reviewed evidence from 2016 to 2023 tells a different story. Research by Macnaughton and Trommelen demonstrates that 40–50 grams of protein can produce significantly greater muscle protein synthesis than the traditional 20–30 gram threshold, particularly following whole-body resistance training. These newer studies employed larger sample sizes and more comprehensive methodologies, suggesting the original limits may have been overly conservative.
The findings underscore an important principle in nutrition science: as evidence evolves, so too must clinical and practical guidance. Individual factors—including lean body mass, exercise type, and training status—appear to matter more than fixed gram thresholds.
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