Effekt av tre månaders ketodiet på kroppssammansättning & prestation hos CrossFit-are

[King Grub]

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 VO2peak 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.

The Three-Month Effects of a Ketogenic Diet on Body Composition, Blood Parameters, and Performance Metrics in CrossFit Trainees: A Pilot Study. Sports 2018, 6(1), 1.

http://www.mdpi.com/2075-4663/6/1/1

[Melker2]

Det var som 17 ��
Jag trodde inte performance på KD skulle fungera så bra på så pass högintensiva moment.

Att det fungerar bra på långlopp har jag egen erfarenhet av men jag tycker 1RM brukar öka när jag laddat kolisar.

[r3mpuh]

Tack för att du postade studien Grub! Fann fullängdaren riktigt intressant/kul(lätt) att läsa. :)

Det var förvisso inga direkta nyheter under parasollet, att man går ned i vikt utav att ligga på kcal underskott likt Keto-personerna rapporterade att de gjorde iaf i slutet av studien, men om jag inte minns helt fel samt uppfattade det hela rätt: Så var Ketogruppens viktnedgång om något en bieffekt av deras kosthållningsbyte & alltså inget angivnet direktiv att ligga på kcal-underskott.

Enda perioderna i mitt liv som jag själv lyckats minska min kroppsvikt under har även de varit utav en kostmässigt glycogen restrikterad art.

Tror det personligen har att göra med en viss form av inadekvat belöningssystemrespons på födointagets energimängd annars/brist på disciplin. Tror jag åt upp mot 20000 kcal under en dag för ett par veckor sedan, medans jag idag kämpade med att få ned 1,5 hamburgare, 4,5 Light Hushållsskivor+2,5 medium ägg. Den aptitnedtryckande effekten som en någorlunda ketogen kosthållning resulterar i rent empiriskt sett, har för mig visat sig vara den enda effektiva stoppklossen på vägen emot min resa till att bli (o)aptitligt fet. *jorgen*