A 28-day carbohydrate-restricted diet improves markers of cardiometabolic health and performance in professional firefighters
© 2019 National Strength and Conditioning Association Waldman, HS, Smith, JW, Lamberth, J, Fountain, BJ, and McAllister, MJ. A 28-day carbohydrate-restricted diet improves markers of cardiometabolic health and performance in professional firefighters. J Strength Cond Res 33(12): 3284–3294, 2019—We investigated the effects of a 4-week ad-libitum, nonketogenic, carbohydrate-restricted (,25% of calories) diet (CRD) on cardiometabolic and performance markers in firefighters (FF). Subjects (n 5 15) completed 9 sessions (trials 1–3 [familiarization], trials 4–6 [baseline], and trials 7–9 [post-CRD]). Following habitual western diet, anthropometric measures were assessed, glucose tolerance measured, and then completed a graded cycling test, maximal Wingate test, and conducted their FF physical performance assessment (FPPA) to measure performance while metabolic variables and perceptual responses were recorded. Subjects then adhered to a CRD for a 4-week duration and returned for repeat testing. Body fat as measured by BodPod, and 7-site skinfold thickness decreased (p, 0.01), and a decrease was observed in blood pressure (BP) (p, 0.01;;5 mm Hg) after CRD. There were no differences found for glucose tolerance, but an increase was found for fat oxidation rates (p, 0.01;;0.07 g·min21) and a decrease in carbohydrate oxidation rates across a range of intensities (p, 0.01;;0.24 g·min21). Finally, the 2.41-km run and pull-up performance during the FPPA improved (p, 0.01;;41 second and 3 repetitions, respectively) and with no differences observed between treatments regarding the Wingate test. To date, this is the first CRD implemented with FF and resulted in decreased fat mass (;2.4 kg), BP, and improvements to performance on the FPPA while preserving high-intensity exercise. These data suggest that a 28-day CRD can benefit markers of health in professional FF without detriments to occupational performance.
Journal of Strength and Conditioning Research
Waldman, H., Smith, J., Lamberth, J., Fountain, B., & McAllister, M.
(2019). A 28-day carbohydrate-restricted diet improves markers of cardiometabolic health and performance in professional firefighters. Journal of Strength and Conditioning Research, 33 (12), 3284-3294.