Does Dieting Affect Your Gains?
Does dieting affect your gains – the effects of lowered energy intakes on muscle mass on trained women
In a recent study, researchers looked at the effect of Low Energy Availability (LEA) on muscle protein synthesis in trained females. LEA arises when the energy intake doesn’t suffice to cover the energy demands from physical exercise and basal physiological operations. This state has been previously linked to several physiological downsides like reproductive dysfunction, but its impact on muscle protein synthesis among exercising females needed to be better understood.
The researchers conducted a randomised controlled trial with 30 eumenorrheic (having normal menstrual cycles) females matched based on their training histories. The participants were assigned to undergo a 10-day LEA or Optimal Energy Availability (OEA) period. During these 10 days, all participants were provided with a standardised diet and partook in a supervised mixed regimen of resistance and cardiovascular exercise training. This setup was designed to monitor the effects of energy availability on muscle protein synthesis closely.
The findings revealed that LEA significantly reduced the daily integrated myofibrillar and sarcoplasmic muscle protein synthesis compared to OEA. Myofibrillar protein synthesis is crucial for muscle strength and mass, while sarcoplasmic protein synthesis is related to the muscle’s metabolic and endurance capacities. The adverse effects of LEA extended beyond just protein synthesis. It also led to notable reductions in lean mass, resting metabolic rate, and even altered hormonal levels, which included a decrease in free androgen index and thyroid hormone concentrations (1)
The study essentially suggests that insufficient energy intake can reduce the muscle-building processes and, by extension, could impair athletic performance and overall physical health. The hormonal changes observed also imply broader physiological disruptions, which could have longer-term health implications if LEA is sustained over an extended period.
Conclusion: It is important to ensure adequate energy availability in females for proper muscle protein synthesis and, by extension, better muscular adaptations to training. This study sheds light on the importance of balanced energy intake for optimal athletic performance and the broader spectrum of physiological well-being. The key takeaway is to stay in a caloric deficit for a short time. Diet phases should be shorter, with periodic breaks for a minimum of 2 weeks to improve training performance and improved hormonal signalling. This ties in with the research I covered recently on “diet breaks” helping adherence to fat loss. A slower rate of weight loss with intermittent breaks would appear to be advantageous for women trying to lose fat and still train.
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