Effects of a 15-Day Low Carbohydrate, High-Fat Diet in Resistance-Trained Men. Issue 11 (November 2018)

• Record Type: Journal Article
• Authors: Waldman, Hunter S.; Krings, Ben M.; Basham, Steven A.; Smith, John Eric W.; Fountain, Brent J.; McAllister, Matthew J.
• Is Part Of: Journal of strength and conditioning research. Volume 32:Issue 11(2018)
• Publication Date: 2018-11
• Subjects: fat oxidation -- carbohydrate restriction -- insulin -- sports nutrition -- isocaloric diet; Physical education and training -- Periodicals; Weight training -- Physiological aspects -- Periodicals; Physical fitness -- Periodicals; 613.7
• DOI: 10.1519/JSC.0000000000002282
• Languages: English
• ISSNs: 1064-8011

Abstract

Abstract : Abstract: Waldman, HS, Krings, BM, Basham, SA, Smith, JW, Fountain, BJ, and McAllister, MJ. Effects of a 15-day low carbohydrate, high-fat diet in resistance-trained men. J Strength Cond Res 32(11): 3103–3111, 2018—This study examined the effects of a 15-day isocaloric low carbohydrate (<25% E), high-fat (>50% E) (LCHF) diet on physiological and metabolic alterations in resistance-trained (RT) men. College-aged RT men ( n = 11) completed 4 V[Combining Dot Above]O2 max tests using treadmill every 5 days during the 15-day trial. Blood was drawn intravenously pre-exercise across each experimental trial for insulin, cortisol, and glucose. Pulmonary data were collected and substrate oxidation (OXI) was calculated during exercise. Body mass decreased ( p < 0.04) with no further changes in anthropometric measures. Time to exhaustion was not affected across each day. Insulin dropped below baseline values ( p < 0.0005). Cortisol increased from baseline to day 5 ( p < 0.004) but returned back to near baseline at day 10, whereas glucose remained within normal range throughout the duration of the study. Carbohydrate (CHO) OXI dropped ( p < 0.001) from baseline to day 5, and fat OXI increased from baseline to day 5 ( p < 0.0001). Heart rate decreased from baseline to day 5 ( p < 0.001) and again from day 10 to 15 ( p < 0.02). Oxygen uptake (V[Combining Dot Above]O2 ) decreased from day 5 to 10 ( p < 0.0001). A nonketo LCHF diet appears to favor RT men by altering metabolic markers without decrements in aerobic performance and be a potential diet intervention used by coaches. However, the reported cardiorespiratory responses should be interpreted reasonably because of the possibility the subjects running economy improved over experimental trials.