Department of Sport and Exercise Sciences, Durham University, Durham, UK.
Physiology, Exercise and Nutrition Research Group, University of Stirling, Stirling, UK.
Eur J Appl Physiol. 2021 Mar;121(3):771-781. doi: 10.1007/s00421-020-04555-7. Epub 2020 Dec 1.
Increasing protein intake during energy restriction (ER) attenuates lean body mass (LBM) loss in trained males. However, whether this relationship exists in trained females is unknown. This study examined the impact of higher compared to lower protein intakes (35% versus 15% of energy intake) on body composition in trained females during 2 weeks of severe ER.
Eighteen well-trained females completed a 1-week energy balanced diet (HD100), followed by a 2-week hypoenergetic (40% ER) diet (HD60). During HD60, participants consumed either a high protein (HP; 35% protein, 15% fat) or lower protein (CON; 15% protein, 35% fat) diet. Body composition, peak power, leg strength, sprint time, and anaerobic endurance were assessed at baseline, pre-HD60, and post-HD60.
Absolute protein intake was reduced during HD60 in the CON group (from 1.6 to 0.9 g·d·kgBM) and maintained in the HP group (~ 1.7 g·d·kgBM). CON and HP groups decreased body mass equally during HD60 (- 1.0 ± 1.1 kg; p = 0.026 and - 1.1 ± 0.7 kg; p = 0.002, respectively) and maintained LBM. There were no interactions between time point and dietary condition on exercise performance.
The preservation of LBM during HD60, irrespective of whether absolute protein intake is maintained or reduced, contrasts with findings in trained males. In trained females, the relationship between absolute protein intake and LBM change during ER warrants further investigation. Future recommendations for protein intake during ER should be expressed relative to body mass, not total energy intake, in trained females.
在能量限制（ER）期间增加蛋白质摄入可减轻训练有素的男性的瘦体重（LBM）损失。然而，这种关系在训练有素的女性中是否存在尚不清楚。本研究在训练有素的女性中，比较了较高与较低蛋白质摄入量（分别占能量摄入的 35%和 15%）对 ER 期间 2 周的身体成分的影响。
18 名训练有素的女性完成了 1 周的能量平衡饮食（HD100），随后进行了 2 周的低能量（40% ER）饮食（HD60）。在 HD60 期间，参与者摄入高蛋白（HP；35%蛋白质，15%脂肪）或低蛋白（CON；15%蛋白质，35%脂肪）饮食。在基线、HD60 前和 HD60 后评估身体成分、最大功率、腿部力量、冲刺时间和无氧耐力。
在 CON 组中，HD60 期间绝对蛋白质摄入量减少（从 1.6 降至 0.9 g·d·kgBM），而在 HP 组中则保持不变（约 1.7 g·d·kgBM）。在 HD60 期间，CON 和 HP 组的体重均相等下降（-1.0±1.1 kg；p=0.026 和-1.1±0.7 kg；p=0.002），并保持了 LBM。在运动表现方面，时间点和饮食条件之间没有交互作用。
在 HD60 期间，无论绝对蛋白质摄入量是保持还是减少，LBM 的保留与训练有素的男性不同。在训练有素的女性中，ER 期间绝对蛋白质摄入与 LBM 变化之间的关系需要进一步研究。在训练有素的女性中，ER 期间蛋白质摄入的建议应相对于体重而不是总能量摄入来表达。
