PMID- 36726396 OWN - NLM STAT- PubMed-not-MEDLINE LR - 20230203 IS - 2624-9367 (Electronic) IS - 2624-9367 (Linking) VI - 4 DP - 2022 TI - Metabolic impact of feeding prior to a 60-min bout of moderate-intensity exercise in females in a fasted state. PG - 1070477 LID - 10.3389/fspor.2022.1070477 [doi] LID - 1070477 AB - BACKGROUND: The metabolic impact of pre-exercise feeding of protein or carbohydrate on fat oxidation and energy expenditure rates, especially, in females, is poorly understood. METHODS: Recreationally active females (n = 15, 32 +/- 10 years, 164.8 +/- 5.6 cm, 63.5 +/- 9.3 kg, 23.4 +/- 3.2 kg/m(2)) completed four testing sessions in a randomized, double-blind, crossover fashion after fasting overnight. Participants ingested isovolumetric and isoenergetic solutions containing either 25 g of whey protein, casein protein, carbohydrate (CHO), or a non-caloric placebo (PLA). Participants then completed 60 min of treadmill exercise at 15% below ventilatory threshold 30 min after ingestion. Respiratory exchange ratio (RER) was evaluated throughout exercise and resting energy expenditure (REE) was assessed pre-exercise, and 0-, 60-, and 120-min post-exercise. RESULTS: A significant condition x time interaction was observed for RER (p = 0.008) during exercise, with CHO exhibiting higher RER values (vs. PLA) at four time points. A significant main effect for condition was observed for carbohydrate (p = 0.001) and fat (p = 0.02) oxidation rates during exercise, with fat oxidation rates being higher in PLA vs. CHO (p = 0.01). When total fat oxidized was calculated across the entire exercise bout, a significant main effect for condition was observed (p = 0.01), with PLA being greater than CHO (p = 0.04). A significant condition x time interaction (p = 0.02) was found for both absolute and normalized REE, with casein and whey protein having significantly higher values than CHO (p < 0.05) immediately post-exercise. CONCLUSION: When compared to a fasted control (PLA), consuming CHO, but not protein, decreased total fat oxidation prior to a 60-min bout of moderate-intensity exercise in females. CI - (c) 2023 Ratliff, Kerksick, Moon, Hagele, Boring, Walden, Gaige, Stecker, Sunderland and Mumford. FAU - Ratliff, Kayla M AU - Ratliff KM AD - Exercise and Performance Nutrition Laboratory, Kinesiology Department, College of Science, Technology, and Health, Lindenwood University, St. Charles, MO, United States. FAU - Kerksick, Chad M AU - Kerksick CM AD - Exercise and Performance Nutrition Laboratory, Kinesiology Department, College of Science, Technology, and Health, Lindenwood University, St. Charles, MO, United States. FAU - Moon, Jessica M AU - Moon JM AD - Exercise and Performance Nutrition Laboratory, Kinesiology Department, College of Science, Technology, and Health, Lindenwood University, St. Charles, MO, United States. FAU - Hagele, Anthony M AU - Hagele AM AD - Exercise and Performance Nutrition Laboratory, Kinesiology Department, College of Science, Technology, and Health, Lindenwood University, St. Charles, MO, United States. FAU - Boring, Johnathan L AU - Boring JL AD - Exercise and Performance Nutrition Laboratory, Kinesiology Department, College of Science, Technology, and Health, Lindenwood University, St. Charles, MO, United States. FAU - Walden, Kylie AU - Walden K AD - Exercise and Performance Nutrition Laboratory, Kinesiology Department, College of Science, Technology, and Health, Lindenwood University, St. Charles, MO, United States. FAU - Gaige, Connor J AU - Gaige CJ AD - Exercise and Performance Nutrition Laboratory, Kinesiology Department, College of Science, Technology, and Health, Lindenwood University, St. Charles, MO, United States. FAU - Stecker, Richard A AU - Stecker RA AD - Exercise and Performance Nutrition Laboratory, Kinesiology Department, College of Science, Technology, and Health, Lindenwood University, St. Charles, MO, United States. FAU - Sunderland, Kyle L AU - Sunderland KL AD - Exercise and Performance Nutrition Laboratory, Kinesiology Department, College of Science, Technology, and Health, Lindenwood University, St. Charles, MO, United States. FAU - Mumford, Petey W AU - Mumford PW AD - Exercise and Performance Nutrition Laboratory, Kinesiology Department, College of Science, Technology, and Health, Lindenwood University, St. Charles, MO, United States. LA - eng PT - Journal Article DEP - 20230116 PL - Switzerland TA - Front Sports Act Living JT - Frontiers in sports and active living JID - 101765780 PMC - PMC9884971 OTO - NOTNLM OT - diet OT - fasted exercise OT - females OT - nutrient timing OT - protein OT - weight loss COIS- The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. EDAT- 2023/02/03 06:00 MHDA- 2023/02/03 06:01 PMCR- 2023/01/16 CRDT- 2023/02/02 01:55 PHST- 2022/10/14 00:00 [received] PHST- 2022/12/09 00:00 [accepted] PHST- 2023/02/02 01:55 [entrez] PHST- 2023/02/03 06:00 [pubmed] PHST- 2023/02/03 06:01 [medline] PHST- 2023/01/16 00:00 [pmc-release] AID - 10.3389/fspor.2022.1070477 [doi] PST - epublish SO - Front Sports Act Living. 2023 Jan 16;4:1070477. doi: 10.3389/fspor.2022.1070477. eCollection 2022.