Kaloriunderskott hämmar muskeltillväxt men inte styrkeökningar

[King Grub]

Short-term energy deficits impair anabolic hormones and muscle protein synthesis. However, the effects of prolonged energy deficits on resistance training (RT) outcomes remain unexplored. Thus, we conducted a systematic review of PubMed and SportDiscus for randomized controlled trials performing RT in an energy deficit (RT+ED) for ≥3 weeks. We first divided the literature into studies with a parallel control group without an energy deficit (RT+CON; Analysis A) and studies without RT+CON (Analysis B). Analysis A consisted of a meta-analysis comparing gains in lean mass (LM) and strength between RT+ED and RT+CON. Studies in Analysis B were matched with separate RT+CON studies for participant and intervention characteristics, and we qualitatively compared the gains in LM and strength between RT+ED and RT+CON. Finally, Analyses A and B were pooled into a meta-regression examining the relationship between the magnitude of the energy deficit and LM. Analysis A showed LM gains were impaired in RT+ED vs RT+CON (effect size (ES) = -0.57, p = .02), but strength gains were comparable between conditions (ES = -0.31, p = .28). Analysis B supports the impairment of LM in RT+ED (ES: -0.11, p = .03) vs RT+CON (ES: 0.20, p < .001) but not strength (RT+ED ES: 0.84; RT+CON ES: 0.81). Finally, our meta-regression demonstrated that an energy deficit of ~500 kcal · day-1 prevented gains in LM. Individuals performing RT to build LM should avoid prolonged energy deficiency, and individuals performing RT to preserve LM during weight loss should avoid energy deficits >500 kcal · day-1.

Scand J Med Sci Sports. 2021 Oct 8. Energy Deficiency Impairs Resistance Training Gains in Lean Mass but not Strength: A Meta-Analysis and Meta-Regression.

https://onlinelibrary.wiley.com/doi/10.1111/sms.14075

[skyffelmördarn]

Verkar stämma bra överens med mina egna personliga erfarenheter efter en viktminskning på ca 20g kg senaste 2 åren.

Jag tror anledningen till att man blir svagare vid deff är helt enkelt för att man inte orkar lika mycket för att man äter mindre och inte för att man "förlorar muskler".

[TotteShaped4Life]

Jag gjorde kostscheman åt en kvinna som gick ner 5-6 kg. För 2 veckor sedan tog hon brons i VM i styrkelyft. Hon blev starkare under tiden och sett i förhållande till att hennes vikt minskade var ju den relativa ökningen imponerande.