{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,13]],"date-time":"2026-09-13T03:09:56Z","timestamp":1789268996186,"version":"build-2803163510"},"reference-count":108,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2025,2,2]],"date-time":"2025-02-02T00:00:00Z","timestamp":1738454400000},"content-version":"vor","delay-in-days":1,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2025,2,1]],"date-time":"2025-02-01T00:00:00Z","timestamp":1738368000000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["J cachexia sarcopenia muscle"],"published-print":{"date-parts":[[2025,2]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Fat mass (FM) and fat\u2010free mass (FFM) are body composition estimates commonly reported in research studies and clinical settings. Recently, fat\u2010free mass indexed to height (fat\u2010free mass index; FFMI) has been shown to be positively associated with impaired insulin sensitivity or insulin resistance. Consequently, hypertrophic resistance training which can increase FFM was also questioned. This paper sets out to evaluate these propositions.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>In this narrative review, we discuss possible reasons that link FFMI to adverse metabolic health outcomes including the limitations of the body composition model that utilizes FFM. The safety of resistance training is also briefly discussed.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Approximately 50% of FFM is comprised of skeletal muscle (SM), with the other 50% being viscera, skin, and bone; FFM and SM cannot be conflated. FFM and fat mass (FM) can both rise with increasing body weight and adiposity, indicating a positive correlation between the two compartments. Risk assessment models not adequately adjusting for this correlation may cause erroneous conclusions, however which way FM and FFM are indexed. Adipose tissue accumulation with weight gain, measured by dual\u2010energy X\u2010ray absorptiometry or bioelectrical impedance, can inflate FFM estimates owing to increased connective tissue. Increased adiposity can also result in fat deposition within skeletal muscle disrupting metabolic health. Importantly, non\u2010skeletal muscle components of the FFM, i.e., the liver and pancreas, both critical in metabolic health, can also be negatively affected by the same lifestyle factors that impact SM. The most frequently used body composition techniques used to estimate FM and FFM cannot detect muscle, liver or pancreas fat infiltration. Prospective evidence demonstrates that resistance training is a safe and effective exercise modality across all ages, especially in older adults experiencing age\u2010 or disease\u2010related declines in muscle health.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>The association between FFM and insulin resistance is largely an artefact driven by inadequate assessment of skeletal muscle. If FM and FFM are used, at the minimum, they need to be evaluated in context with one another. Body composition methods, such as magnetic resonance imaging, which measures skeletal muscle rather than fat\u2010free mass, and adipose tissue as well as muscle ectopic fat, are preferred methods. Resistance training is important in achieving and maintaining good health across the lifespan. While strength and power are critical components of resistance training, the reduction of skeletal mass through ageing or disease may require hypertrophic training to mitigate and slow down the progression of this often\u2010inevitable process.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/jcsm.13714","type":"journal-article","created":{"date-parts":[[2025,2,3]],"date-time":"2025-02-03T02:24:11Z","timestamp":1738549451000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":23,"title":["Fat\u2010Free Mass: Friend or Foe to Metabolic Health?"],"prefix":"10.1002","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1068-5122","authenticated-orcid":false,"given":"Christopher\u00a0J.","family":"Oliver","sequence":"first","affiliation":[{"name":"Faculty of Health Southern Cross University  Lismore NSW Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mike","family":"Climstein","sequence":"additional","affiliation":[{"name":"Clinical and Health Services Faculty of Health Southern Cross University  Bilinga QLD Australia"},{"name":"Exercise and Sport Science Exercise, Health &amp; Performance Faculty Research Group Faculty of Health Sciences University of Sydney  Sydney NSW Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nedeljka","family":"Rosic","sequence":"additional","affiliation":[{"name":"Faculty of Health Southern Cross University  Bilinga QLD Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anja","family":"Bosy\u2010Westphal","sequence":"additional","affiliation":[{"name":"Institut f\u00fcr Humanern\u00e4hrung und Lebensmittelkunde Christian\u2010Albrechts\u2010Universit\u00e4t zu Kiel  Kiel Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Grant","family":"Tinsley","sequence":"additional","affiliation":[{"name":"Department of Kinesiology &amp; Sport Management Texas Tech University  Lubbock Texas USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephen","family":"Myers","sequence":"additional","affiliation":[{"name":"Faculty of Health Southern Cross University  Lismore NSW Australia"},{"name":"NatMed\u2010Research  Evans Head NSW Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2025,2,2]]},"reference":[{"key":"e_1_2_5_2_1","doi-asserted-by":"publisher","DOI":"10.1002\/jcsm.12856"},{"key":"e_1_2_5_3_1","doi-asserted-by":"publisher","DOI":"10.1002\/jcsm.12520"},{"key":"e_1_2_5_4_1","doi-asserted-by":"publisher","DOI":"10.1111\/cen.14085"},{"key":"e_1_2_5_5_1","doi-asserted-by":"publisher","DOI":"10.1007\/s40520-018-0993-y"},{"key":"e_1_2_5_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.arr.2016.04.007"},{"key":"e_1_2_5_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.pcd.2020.05.003"},{"key":"e_1_2_5_8_1","doi-asserted-by":"publisher","DOI":"10.3389\/fphys.2021.656909"},{"key":"e_1_2_5_9_1","doi-asserted-by":"publisher","DOI":"10.1177\/0148607114550189"},{"key":"e_1_2_5_10_1","doi-asserted-by":"publisher","DOI":"10.1093\/ajcn\/56.1.19"},{"key":"e_1_2_5_11_1","doi-asserted-by":"publisher","DOI":"10.1152\/ajpendo.2002.282.1.E132"},{"key":"e_1_2_5_12_1","doi-asserted-by":"publisher","DOI":"10.1159\/000499607"},{"key":"e_1_2_5_13_1","doi-asserted-by":"publisher","DOI":"10.3390\/ijms24054651"},{"key":"e_1_2_5_14_1","doi-asserted-by":"publisher","DOI":"10.1038\/ejcn.2012.138"},{"key":"e_1_2_5_15_1","doi-asserted-by":"publisher","DOI":"10.1080\/07315724.1991.10718128"},{"key":"e_1_2_5_16_1","doi-asserted-by":"publisher","DOI":"10.1007\/s11357-014-9741-1"},{"key":"e_1_2_5_17_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00592-020-01594-6"},{"key":"e_1_2_5_18_1","doi-asserted-by":"publisher","DOI":"10.1089\/chi.2021.0157"},{"key":"e_1_2_5_19_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.diabres.2016.07.018"},{"key":"e_1_2_5_20_1","doi-asserted-by":"publisher","DOI":"10.1589\/jpts.28.1036"},{"key":"e_1_2_5_21_1","doi-asserted-by":"publisher","DOI":"10.1111\/dme.13789"},{"key":"e_1_2_5_22_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-018-37347-3"},{"key":"e_1_2_5_23_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0263213"},{"key":"e_1_2_5_24_1","doi-asserted-by":"publisher","DOI":"10.1589\/jpts.34.353"},{"key":"e_1_2_5_25_1","doi-asserted-by":"publisher","DOI":"10.1017\/S1368980014001918"},{"key":"e_1_2_5_26_1","doi-asserted-by":"publisher","DOI":"10.3945\/ajcn.113.078576"},{"key":"e_1_2_5_27_1","doi-asserted-by":"publisher","DOI":"10.1038\/ejcn.2017.31"},{"key":"e_1_2_5_28_1","doi-asserted-by":"publisher","DOI":"10.1111\/obr.13190"},{"key":"e_1_2_5_29_1","doi-asserted-by":"publisher","DOI":"10.14218\/JCTH.2020.00065"},{"key":"e_1_2_5_30_1","doi-asserted-by":"publisher","DOI":"10.4093\/dmj.2020.0277"},{"key":"e_1_2_5_31_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41574-022-00784-2"},{"key":"e_1_2_5_32_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00330-023-09856-x"},{"key":"e_1_2_5_33_1","first-page":"155","article-title":"Training Strategies to Optimize Cardiovascular Durability and Life Expectancy","volume":"120","author":"O'Keefe J. 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