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      The Three-Month Effects of a Ketogenic Diet on Body Composition, Blood Parameters, and Performance Metrics in CrossFit Trainees: A Pilot Study

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          Abstract

          Adopting low carbohydrate, ketogenic diets remains a controversial issue for individuals who resistance train given that this form of dieting has been speculated to reduce skeletal muscle glycogen levels and stifle muscle anabolism. We sought to characterize the effects of a 12-week ketogenic diet (KD) on body composition, metabolic, and performance parameters in participants who trained recreationally at a local CrossFit facility. Twelve participants (nine males and three females, 31 ± 2 years of age, 80.3 ± 5.1 kg body mass, 22.9 ± 2.3% body fat, 1.37 back squat: body mass ratio) were divided into a control group (CTL; n = 5) and a KD group ( n = 7). KD participants were given dietary guidelines to follow over 12 weeks while CTL participants were instructed to continue their normal diet throughout the study, and all participants continued their CrossFit training routine for 12 weeks. Pre, 2.5-week, and 12-week anaerobic performance tests were conducted, and pre- and 12-week tests were performed for body composition using dual X-ray absorptiometry (DXA) and ultrasound, resting energy expenditure (REE), blood-serum health markers, and aerobic capacity. Additionally, blood beta hydroxybutyrate (BHB) levels were measured weekly. Blood BHB levels were 2.8- to 9.5-fold higher in KD versus CTL throughout confirming a state of nutritional ketosis. DXA fat mass decreased by 12.4% in KD ( p = 0.053). DXA total lean body mass changes were not different between groups, although DXA dual-leg lean mass decreased in the KD group by 1.4% ( p = 0.068), and vastus lateralis thickness values decreased in the KD group by ~8% ( p = 0.065). Changes in fasting glucose, HDL cholesterol, and triglycerides were similar between groups, although LDL cholesterol increased ~35% in KD ( p = 0.048). Between-group changes in REE, one-repetition maximum (1-RM) back squat, 400 m run times, and VO 2peak were similar between groups. While our n-sizes were limited, these preliminary data suggest that adopting a ketogenic diet causes marked reductions in whole-body adiposity while not impacting performance measures in recreationally-trained CrossFit trainees. Whether decrements in dual-leg muscle mass and vastus lateralis thickness in KD participants were due to fluid shifts remain unresolved, and increased LDL-C in these individuals warrants further investigation.

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          Most cited references 24

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          A randomized trial comparing a very low carbohydrate diet and a calorie-restricted low fat diet on body weight and cardiovascular risk factors in healthy women.

          Untested alternative weight loss diets, such as very low carbohydrate diets, have unsubstantiated efficacy and the potential to adversely affect cardiovascular risk factors. Therefore, we designed a randomized, controlled trial to determine the effects of a very low carbohydrate diet on body composition and cardiovascular risk factors. Subjects were randomized to 6 months of either an ad libitum very low carbohydrate diet or a calorie-restricted diet with 30% of the calories as fat. Anthropometric and metabolic measures were assessed at baseline, 3 months, and 6 months. Fifty-three healthy, obese female volunteers (mean body mass index, 33.6 +/- 0.3 kg/m(2)) were randomized; 42 (79%) completed the trial. Women on both diets reduced calorie consumption by comparable amounts at 3 and 6 months. The very low carbohydrate diet group lost more weight (8.5 +/- 1.0 vs. 3.9 +/- 1.0 kg; P < 0.001) and more body fat (4.8 +/- 0.67 vs. 2.0 +/- 0.75 kg; P < 0.01) than the low fat diet group. Mean levels of blood pressure, lipids, fasting glucose, and insulin were within normal ranges in both groups at baseline. Although all of these parameters improved over the course of the study, there were no differences observed between the two diet groups at 3 or 6 months. beta- Hydroxybutyrate increased significantly in the very low carbohydrate group at 3 months (P = 0.001). Based on these data, a very low carbohydrate diet is more effective than a low fat diet for short-term weight loss and, over 6 months, is not associated with deleterious effects on important cardiovascular risk factors in healthy women.
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            A high-fat, ketogenic diet induces a unique metabolic state in mice.

            Ketogenic diets have been used as an approach to weight loss on the basis of the theoretical advantage of a low-carbohydrate, high-fat diet. To evaluate the physiological and metabolic effects of such diets on weight we studied mice consuming a very-low-carbohydrate, ketogenic diet (KD). This diet had profound effects on energy balance and gene expression. C57BL/6 mice animals were fed one of four diets: KD; a commonly used obesogenic high-fat, high-sucrose diet (HF); 66% caloric restriction (CR); and control chow (C). Mice on KD ate the same calories as mice on C and HF, but weight dropped and stabilized at 85% initial weight, similar to CR. This was consistent with increased energy expenditure seen in animals fed KD vs. those on C and CR. Microarray analysis of liver showed a unique pattern of gene expression in KD, with increased expression of genes in fatty acid oxidation pathways and reduction in lipid synthesis pathways. Animals made obese on HF and transitioned to KD lost all excess body weight, improved glucose tolerance, and increased energy expenditure. Analysis of key genes showed similar changes as those seen in lean animals placed directly on KD. Additionally, AMP kinase activity was increased, with a corresponding decrease in ACC activity. These data indicate that KD induces a unique metabolic state congruous with weight loss.
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              Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet.

              We recently proposed that the biological markers improved by carbohydrate restriction were precisely those that define the metabolic syndrome (MetS), and that the common thread was regulation of insulin as a control element. We specifically tested the idea with a 12-week study comparing two hypocaloric diets (approximately 1,500 kcal): a carbohydrate-restricted diet (CRD) (%carbohydrate:fat:protein = 12:59:28) and a low-fat diet (LFD) (56:24:20) in 40 subjects with atherogenic dyslipidemia. Both interventions led to improvements in several metabolic markers, but subjects following the CRD had consistently reduced glucose (-12%) and insulin (-50%) concentrations, insulin sensitivity (-55%), weight loss (-10%), decreased adiposity (-14%), and more favorable triacylglycerol (TAG) (-51%), HDL-C (13%) and total cholesterol/HDL-C ratio (-14%) responses. In addition to these markers for MetS, the CRD subjects showed more favorable responses to alternative indicators of cardiovascular risk: postprandial lipemia (-47%), the Apo B/Apo A-1 ratio (-16%), and LDL particle distribution. Despite a threefold higher intake of dietary saturated fat during the CRD, saturated fatty acids in TAG and cholesteryl ester were significantly decreased, as was palmitoleic acid (16:1n-7), an endogenous marker of lipogenesis, compared to subjects consuming the LFD. Serum retinol binding protein 4 has been linked to insulin-resistant states, and only the CRD decreased this marker (-20%). The findings provide support for unifying the disparate markers of MetS and for the proposed intimate connection with dietary carbohydrate. The results support the use of dietary carbohydrate restriction as an effective approach to improve features of MetS and cardiovascular risk.
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                Author and article information

                Journal
                Sports (Basel)
                Sports (Basel)
                sports
                Sports
                MDPI
                2075-4663
                09 January 2018
                March 2018
                : 6
                : 1
                Affiliations
                [1 ]School of Kinesiology, Auburn University, Auburn, AL 36849, USA; kephartw@ 123456uww.edu (W.C.K.); par0021@ 123456auburn.edu (P.A.R.); pwm0009@ 123456auburn.edu (P.W.M.); mzr0049@ 123456auburn.edu (M.A.R.); moblecb@ 123456auburn.edu (C.B.M.); jmartin@ 123456auburn.vcom.edu (J.S.M.); kyoung@ 123456auburn.vcom.edu (K.C.Y.)
                [2 ]Department of Health, Physical Education, Recreation and Coaching, University of Wisconsin-Whitewater, Whitewater, WI 53190, USA
                [3 ]Department of Nutrition, Dietetics and Hospitality Management, Auburn University, Auburn, AL 36849, USA; cdp0017@ 123456auburn.edu (C.D.P.); huggikw@ 123456auburn.edu (K.W.H.)
                [4 ]Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL 36830, USA
                [5 ]Applied Sports Performance Institute, Tampa, FL 33607, USA; rlowery@ 123456theaspi.com (R.P.L.); jwilson@ 123456theaspi.com (J.M.W.)
                Author notes
                [* ]Correspondence: mdr0024@ 123456auburn.edu ; Tel.: +1-334-844-1925; Fax: +1-334-944-1467
                [†]

                Both authors equally contributed to this work.

                Article
                sports-06-00001
                10.3390/sports6010001
                5969192
                © 2018 by the authors.

                Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( http://creativecommons.org/licenses/by/4.0/).

                Categories
                Article

                strength, ketogenic diet, body composition, power

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