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    "kind": "note",
    "key": "morton-2018",
    "id": "TAP-RDN-0081",
    "locale": "en",
    "path": "/research/morton-2018/",
    "title": "TAP reading note: A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults",
    "description": "Across 49 trials, supplementation added an average 0.30 kg of fat-free mass (95% CI 0.09–0.52) and 2.49 kg in one-repetition-maximum strength (0.64–4.33) to resistance-training gains. The estimated daily-intake breakpoint was 1.62 g/kg/day, with considerable uncertainty.",
    "rights": "© The Allostasis Project. All rights reserved. Reproduction or adaptation requires separate permission, subject to applicable legal exceptions.",
    "version": "1.0",
    "updatedAt": "2026-11-13",
    "editorial": {
      "contentType": "evidence-review",
      "reviewState": "draft",
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      "updatedAt": "2026-11-13",
      "version": "1.0",
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      "workflow": {
        "ai": {
          "usage": "used",
          "system": "OpenAI Codex",
          "scope": "Source-based synthesis, drafting and translation. Consulted materials and access limits are described in the reading notes.",
          "version": "1.0",
          "tasks": [
            "Literature comparison and evidence extraction",
            "Bilingual explanatory writing and source-linked tables"
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      "revisions": []
    },
    "original": {
      "id": "morton-2018",
      "title": "A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults",
      "authors": "Robert W. Morton et al.",
      "journal": "British Journal of Sports Medicine",
      "year": "2018",
      "url": "https://doi.org/10.1136/bjsports-2017-097608",
      "doi": "10.1136/bjsports-2017-097608",
      "pmid": "28698222"
    },
    "references": [
      {
        "id": "morton-2018",
        "title": "A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults",
        "authors": "Robert W. Morton et al.",
        "journal": "British Journal of Sports Medicine",
        "year": "2018",
        "url": "https://doi.org/10.1136/bjsports-2017-097608",
        "doi": "10.1136/bjsports-2017-097608",
        "pmid": "28698222"
      }
    ],
    "sections": [
      {
        "id": "finding",
        "title": "What the study found",
        "paragraphs": [
          "Across 49 trials, supplementation added an average 0.30 kg of fat-free mass (95% CI 0.09–0.52) and 2.49 kg in one-repetition-maximum strength (0.64–4.33) to resistance-training gains. The estimated daily-intake breakpoint was 1.62 g/kg/day, with considerable uncertainty."
        ]
      },
      {
        "id": "limits",
        "title": "Scope & limitations",
        "paragraphs": [
          "49 randomized trials; 1,863 healthy adults, with a mixture of ages and training histories. Energy-restricted participants were excluded.",
          "The breakpoint analysis used 42 study arms and 723 participants: 95% CI 1.03–2.20 g/kg/day; the segmented model comparison did not reach conventional significance (p=.079). This is a study-level estimate, not an individual requirement, a safety ceiling or a proven optimum. Women and older adults had less evidence."
        ]
      },
      {
        "id": "sample",
        "title": "Population & sample",
        "paragraphs": [
          "49 randomized trials; 1,863 healthy adults, with a mixture of ages and training histories. Energy-restricted participants were excluded."
        ]
      },
      {
        "id": "exposure",
        "title": "Exposure or intervention",
        "paragraphs": [
          "Protein supplements plus resistance training versus training with placebo or no supplement; food-based and isolated-protein interventions were included."
        ]
      },
      {
        "id": "outcomes",
        "title": "Outcomes",
        "paragraphs": [
          "Changes in fat-free mass, one-repetition-maximum strength and muscle size; these are not everyday fatigue or whole-body recovery measures."
        ]
      },
      {
        "id": "duration",
        "title": "Time frame",
        "paragraphs": [
          "Training lasted at least six weeks; publications spanned 1962–2016. Published online in 2017, in the 2018 journal issue."
        ]
      },
      {
        "id": "funding",
        "title": "Research funding",
        "paragraphs": [
          "Stuart M. Phillips acknowledged Canada Research Chairs, Canadian Institutes of Health Research and Natural Sciences and Engineering Research Council of Canada support."
        ]
      },
      {
        "id": "conflicts",
        "title": "Research conflicts of interest",
        "paragraphs": [
          "Phillips disclosed grants, travel and presentation honoraria from the US National Dairy Council, which also supported trials included in the analysis."
        ]
      },
      {
        "id": "basis",
        "title": "Reading scope",
        "paragraphs": [
          "PMC full text: eligibility, pooled results, breakpoint analysis and Figure 5, limitations and declarations. Individual trial data and all supplementary analyses were not independently reanalysed."
        ],
        "links": [
          {
            "label": "Full text in PubMed Central",
            "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC5867436/"
          }
        ]
      }
    ]
  }
}