{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,10]],"date-time":"2026-10-10T06:25:07Z","timestamp":1791613507157,"version":"4.3.4"},"reference-count":44,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2025,11,25]],"date-time":"2025-11-25T00:00:00Z","timestamp":1764028800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Institute of Education, Nanyang Technological University, Singapore"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Background\/Objectives: Long-term alternate-day fasting (ADF) effectively combats obesity, but its short-term effects are less clear. Like other diets, ADF-induced weight loss often includes muscle loss, and whether protein supplementation mitigates this is uncertain. This study examined the effects of short-term ADF on body composition and health and whether protein supplementation preserves muscle mass during weight loss in young Asian men with an unhealthy BMI (\u226523.0 kg\/m2). Methods: Twenty participants were recruited for a single-arm trial to address the first objective, and twenty-six participants were randomly assigned to a control (C) or protein group (P) in a follow-up trial to address the second objective. The participants alternated between feeding (ad libitum) and fasting (400\u2013600 kcal consumed between 12 and 2 PM) days for four weeks. The participants in P consumed 25 g of whey protein as part of the fasting-day meal. Pre\u2013post body composition was assessed using bioelectrical impedance analysis. Anthropometry, fasting blood glucose (FG), and resting blood pressure (BP) were measured weekly. Results: Since interaction effects were absent, data from all three groups were combined for analyses. Four weeks of ADF significantly (p &lt; 0.001) reduced body (2.4 kg), fat (1.6 kg), and fat-free (0.8 kg) mass. BP and FG levels remained unchanged (p = 0.753\u20130.919). No significant differences were detected between the C and P groups for any of the measures. Conclusions: Short-term ADF effectively reduced body and fat mass, but it also reduced muscle mass, and this reduction was not attenuated by low-dose protein supplementation (25 g) during fasting days. Future studies should explore the effectiveness of protein or leucine supplementation, throughout the feeding and fasting days, in terms of preserving muscle during weight loss.<\/jats:p>","DOI":"10.3390\/nu17233691","type":"journal-article","created":{"date-parts":[[2025,11,25]],"date-time":"2025-11-25T15:29:47Z","timestamp":1764084587000},"page":"3691","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Effects of Four Weeks of Alternate-Day Fasting with or Without Protein Supplementation\u2014A Randomized Controlled Trial"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7655-9834","authenticated-orcid":false,"given":"Benedict Wei Jun","family":"Pang","sequence":"first","affiliation":[{"name":"Physical Education and Sports Science, National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore"},{"name":"Geriatric Education and Research Institute, Singapore 768024, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1972-1150","authenticated-orcid":false,"given":"Yifan","family":"Yang","sequence":"additional","affiliation":[{"name":"Physical Education and Sports Science, National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore"},{"name":"Science of Learning in Education Centre, National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nur","family":"Rashiqah","sequence":"additional","affiliation":[{"name":"Physical Education and Sports Science, National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christopher Bingqiang","family":"Huang","sequence":"additional","affiliation":[{"name":"Physical Education and Sports Science, National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Da Wei","family":"Sim","sequence":"additional","affiliation":[{"name":"Physical Education and Sports Science, National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,11,25]]},"reference":[{"key":"ref_1","unstructured":"WHO (2024, August 30). Global Health Observatory (GHO) Data\u2014Overweight and Obesity 2022. Available online: https:\/\/www.who.int\/gho\/ncd\/risk_factors\/overweight_obesity\/obesity_adults\/en\/."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"WHO (2004). Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet, 363, 157\u2013163.","DOI":"10.1016\/S0140-6736(03)15268-3"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Chen, K.K., Wee, S.-L., Pang, B., Lau, L.K., Jabbar, K.A., Seah, W.T., and Ng, T.P. (2021). Relationship between BMI with percentage body fat and obesity in Singaporean adults\u2014The Yishun Study. BMC Public Health, 21.","DOI":"10.1186\/s12889-021-11070-7"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"815","DOI":"10.1016\/S0140-6736(11)60814-3","article-title":"Health and economic burden of the projected obesity trends in the USA and the UK","volume":"378","author":"Wang","year":"2011","journal-title":"Lancet"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"110801","DOI":"10.1016\/j.nut.2020.110801","article-title":"Effects of intermittent fasting and energy-restricted diets on lipid profile: A systematic review and meta-analysis","volume":"77","author":"Meng","year":"2020","journal-title":"Nutrition"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Cho, Y., Hong, N., Kim, K.W., Cho, S.J., Lee, M., Lee, Y.H., Lee, Y.H., Kang, E.S., Cha, B.S., and Lee, B.W. (2019). The Effectiveness of Intermittent Fasting to Reduce Body Mass Index and Glucose Metabolism: A Systematic Review and Meta-Analysis. J. Clin. Med., 8.","DOI":"10.3390\/jcm8101645"},{"key":"ref_7","first-page":"117","article-title":"Intermittent fasting and weight loss: Systematic review","volume":"66","author":"Welton","year":"2020","journal-title":"Can. Fam. Physician"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"371","DOI":"10.1146\/annurev-nutr-071816-064634","article-title":"Metabolic Effects of Intermittent Fasting","volume":"37","author":"Patterson","year":"2017","journal-title":"Annu. Rev. Nutr."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1186\/1475-2891-12-146","article-title":"Alternate day fasting for weight loss in normal weight and overweight subjects: A randomized controlled trial","volume":"12","author":"Varady","year":"2013","journal-title":"Nutr. J."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"154336","DOI":"10.1016\/j.metabol.2020.154336","article-title":"Effect of alternate-day fasting on obesity and cardiometabolic risk: A systematic review and meta-analysis","volume":"111","author":"Park","year":"2020","journal-title":"Metab. Clin. Exp."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Cui, Y., Cai, T., Zhou, Z., Mu, Y., Lu, Y., Gao, Z., Wu, J., and Zhang, Y. (2020). Health Effects of Alternate-Day Fasting in Adults: A Systematic Review and Meta-Analysis. Front. Nutr., 7.","DOI":"10.3389\/fnut.2020.586036"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1002\/osp4.52","article-title":"Alternate-day versus daily energy restriction diets: Which is more effective for weight loss? A systematic review and meta-analysis","volume":"2","author":"Alhamdan","year":"2016","journal-title":"Obes. Sci. Pract."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"930","DOI":"10.1001\/jamainternmed.2017.0936","article-title":"Effect of Alternate-Day Fasting on Weight Loss, Weight Maintenance, and Cardioprotection Among Metabolically Healthy Obese Adults: A Randomized Clinical Trial","volume":"177","author":"Trepanowski","year":"2017","journal-title":"JAMA Intern. Med."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"462","DOI":"10.1016\/j.cmet.2019.07.016","article-title":"Alternate Day Fasting Improves Physiological and Molecular Markers of Aging in Healthy, Non-obese Humans","volume":"30","author":"Stekovic","year":"2019","journal-title":"Cell Metab."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1093\/ajcn\/81.1.69","article-title":"Alternate-day fasting in nonobese subjects: Effects on body weight, body composition, and energy metabolism","volume":"81","author":"Heilbronn","year":"2005","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2128","DOI":"10.1152\/japplphysiol.00683.2005","article-title":"Effect of intermittent fasting and refeeding on insulin action in healthy men","volume":"99","author":"Halberg","year":"2005","journal-title":"J. Appl. Physiol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1186\/1475-2891-9-35","article-title":"Dietary and physical activity adaptations to alternate day modified fasting: Implications for optimal weight loss","volume":"9","author":"Klempel","year":"2010","journal-title":"Nutr. J."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"eabd8034","DOI":"10.1126\/scitranslmed.abd8034","article-title":"A randomized controlled trial to isolate the effects of fasting and energy restriction on weight loss and metabolic health in lean adults","volume":"13","author":"Templeman","year":"2021","journal-title":"Sci. Transl. Med."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1138","DOI":"10.3945\/ajcn.2009.28380","article-title":"Short-term modified alternate-day fasting: A novel dietary strategy for weight loss and cardioprotection in obese adults","volume":"90","author":"Varady","year":"2009","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"212","DOI":"10.1016\/j.clnu.2025.08.033","article-title":"Alternate-day fasting elicits larger changes in fat mass than time-restricted eating in adults without obesity\u2014A randomized clinical trial","volume":"53","author":"Derron","year":"2025","journal-title":"Clin. Nutr."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1186\/s12970-017-0174-y","article-title":"International society of sports nutrition position stand: Diets and body composition","volume":"14","author":"Aragon","year":"2017","journal-title":"J. Int. Soc. Sports Nutr."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"S105","DOI":"10.1017\/S0007114512002589","article-title":"Dietary protein\u2014Its role in satiety, energetics, weight loss and health","volume":"108","author":"Lemmens","year":"2012","journal-title":"Br. J. Nutr."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1281","DOI":"10.3945\/ajcn.112.044321","article-title":"Effects of energy-restricted high-protein, low-fat compared with standard-protein, low-fat diets: A meta-analysis of randomized controlled trials","volume":"96","author":"Wycherley","year":"2012","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"374","DOI":"10.1016\/j.physbeh.2012.08.004","article-title":"Relatively high-protein or \u2018low-carb\u2019 energy-restricted diets for body weight loss and body weight maintenance?","volume":"107","author":"Soenen","year":"2012","journal-title":"Physiol. Behav."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1038\/ijo.2015.182","article-title":"Protein intake and lean body mass preservation during energy intake restriction in overweight older adults","volume":"40","author":"Backx","year":"2016","journal-title":"Int. J. Obes."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1370","DOI":"10.1002\/oby.20353","article-title":"Alternate day fasting and endurance exercise combine to reduce body weight and favorably alter plasma lipids in obese humans","volume":"21","author":"Bhutani","year":"2013","journal-title":"Obesity"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1476","DOI":"10.1007\/s11695-014-1190-5","article-title":"Validation study of multi-frequency bioelectrical impedance with dual-energy X-ray absorptiometry among obese patients","volume":"24","author":"Faria","year":"2014","journal-title":"Obes. Surg."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Ram\u00edrez-V\u00e9lez, R., Tordecilla-Sanders, A., Correa-Bautista, J.E., Gonz\u00e1lez-Ru\u00edz, K., Gonz\u00e1lez-Jim\u00e9nez, E., Triana-Reina, H.R., Garc\u00eda-Hermoso, A., and Schmidt-RioValle, J. (2018). Validation of multi-frequency bioelectrical impedance analysis versus dual-energy X-ray absorptiometry to measure body fat percentage in overweight\/obese Colombian adults. Am. J. Hum. Biol., 30.","DOI":"10.1002\/ajhb.23071"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1159\/000176061","article-title":"Accuracy of bioelectrical impedance consumer devices for measurement of body composition in comparison to whole body magnetic resonance imaging and dual X-ray absorptiometry","volume":"1","author":"Later","year":"2008","journal-title":"Obes. Facts"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2152","DOI":"10.1038\/oby.2010.54","article-title":"Improvements in coronary heart disease risk indicators by alternate-day fasting involve adipose tissue modulations","volume":"18","author":"Bhutani","year":"2010","journal-title":"Obesity"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1007\/s10389-006-0024-x","article-title":"Development of the World Health Organization Global Physical Activity Questionnaire (GPAQ)","volume":"14","author":"Armstrong","year":"2006","journal-title":"J. Public Health"},{"key":"ref_32","unstructured":"(2024, February 02). NHLBI Obesity Education Initiative Expert Panel on the Identification, Evaluation, and Treatment of Obesity in Adults (US). Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report, Available online: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK2003\/."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1","DOI":"10.2165\/00007256-200535010-00001","article-title":"Diet and exercise for weight loss: A review of current issues","volume":"35","author":"Volek","year":"2005","journal-title":"Sports Med."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1363","DOI":"10.1152\/jappl.1986.61.4.1363","article-title":"Metabolic responses to exercise after fasting","volume":"61","author":"Dohm","year":"1986","journal-title":"J. Appl. Physiol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"292S","DOI":"10.1093\/ajcn\/56.1.292S","article-title":"Glycogen storage: Illusions of easy weight loss, excessive weight regain, and distortions in estimates of body composition","volume":"56","author":"Kreitzman","year":"1992","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1038\/ejcn.2015.195","article-title":"Intermittent energy restriction and weight loss: A systematic review","volume":"70","author":"Davis","year":"2016","journal-title":"Eur. J. Clin. Nutr."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"511","DOI":"10.3945\/an.116.014506","article-title":"Preserving Healthy Muscle during Weight Loss","volume":"8","author":"Cava","year":"2017","journal-title":"Adv. Nutr."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Larsen, A.E., Bibby, B.M., and Hansen, M. (2018). Effect of a Whey Protein Supplement on Preservation of Fat Free Mass in Overweight and Obese Individuals on an Energy Restricted Very Low Caloric Diet. Nutrients, 10.","DOI":"10.3390\/nu10121918"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2891","DOI":"10.1001\/jama.299.24.2891","article-title":"The Recommended Dietary Allowance of Protein: A Misunderstood Concept","volume":"299","author":"Wolfe","year":"2008","journal-title":"JAMA"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"276","DOI":"10.3945\/ajcn.113.068775","article-title":"Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar protein synthesis in young men: A double-blind, randomized trial","volume":"99","author":"Breen","year":"2014","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1088","DOI":"10.1093\/jn\/nxy091","article-title":"Leucine, Not Total Protein, Content of a Supplement Is the Primary Determinant of Muscle Protein Anabolic Responses in Healthy Older Women","volume":"148","author":"Devries","year":"2018","journal-title":"J. Nutr."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1093\/ajcn\/82.1.41","article-title":"A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations","volume":"82","author":"Weigle","year":"2005","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1780","DOI":"10.1017\/S0007114511007422","article-title":"Resistance exercise enhances myofibrillar protein synthesis with graded intakes of whey protein in older men","volume":"108","author":"Yang","year":"2012","journal-title":"Br. J. Nutr."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"1213","DOI":"10.1249\/MSS.0b013e31816a85ce","article-title":"Exercise attenuates the weight-loss-induced reduction in muscle mass in frail obese older adults","volume":"40","author":"Frimel","year":"2008","journal-title":"Med. Sci. Sports Exerc."}],"container-title":["Nutrients"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6643\/17\/23\/3691\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,11,25]],"date-time":"2025-11-25T15:41:04Z","timestamp":1764085264000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6643\/17\/23\/3691"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,11,25]]},"references-count":44,"journal-issue":{"issue":"23","published-online":{"date-parts":[[2025,12]]}},"alternative-id":["nu17233691"],"URL":"https:\/\/doi.org\/10.3390\/nu17233691","relation":{},"ISSN":["2072-6643"],"issn-type":[{"value":"2072-6643","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,11,25]]}}}