Karl J Philip, Smith Tracey J, Wilson Marques A, Bukhari Asma S, Pasiakos Stefan M, McClung Holly L, McClung James P, Lieberman Harris R
Military Nutrition Division, US Army Research Institute of Environmental Medicine, 10 General Greene Ave, Bldg 42, Natick, MA 01760, USA.
Military Nutrition Division, US Army Research Institute of Environmental Medicine, 10 General Greene Ave, Bldg 42, Natick, MA 01760, USA.
Metabolism. 2016 Apr;65(4):416-27. doi: 10.1016/j.metabol.2015.11.001. Epub 2015 Nov 6.
Military personnel frequently endure intermittent periods of severe energy deficit which can compromise health and performance. Physiologic factors contributing to underconsumption, and the subsequent drive to overeat, are not fully characterized. This study aimed to identify associations between appetite, metabolic homeostasis and endocrine responses during and following severe, short-term energy deprivation.
Twenty-three young adults (17M/6F, 21±3years, BMI 25±3kg/m(2)) participated in a randomized, controlled, crossover trial. During separate 48-h periods, participants increased habitual energy expenditure by 1647±345kcal/d (mean±SD) through prescribed exercise at 40-65% VO2peak, and consumed provided isovolumetric diets designed to maintain energy balance at the elevated energy expenditure (EB; 36±93kcal/d energy deficit) or to produce a severe energy deficit (ED; 3681±716kcal/d energy deficit). Appetite, markers of metabolic homeostasis and endocrine mediators of appetite and substrate availability were periodically measured. Ad libitum energy intake was measured over 36h following both experimental periods.
Appetite increased during ED and was greater than during EB despite maintenance of diet volume (P=0.004). Ad libitum energy intake was 907kcal/36h [95% CI: 321, 1493kcal/36h, P=0.004] higher following ED compared to following EB. Serum beta-hydroxybutyrate, free fatty acids, branched-chain amino acids, dehydroepiandrosterone-sulfate (DHEA-S) and cortisol concentrations were higher (P<0.001 for all), whereas whole-body protein balance was more negative (P<0.001), and serum glucose, insulin, and leptin concentrations were lower (P<0.001 for all) during ED relative to during EB. Cortisol concentrations, but not any other hormone or metabolic substrate, were inversely associated with satiety during EB (R(2)=0.23, P=0.04). In contrast, serum glucose and DHEA-S concentrations were inversely associated with satiety during ED (R(2)=0.68, P<0.001). No associations between physiologic variables measured during EB and ad libitum energy intake following EB were observed. However, serum leptin and net protein balance measured during ED were inversely associated with ad libitum energy intake following ED (R(2)=0.48, P=0.01).
These findings suggest that changes in metabolic homeostasis during energy deprivation modulate appetite independent of reductions in diet volume. Following energy deprivation, physiologic signals of adipose and lean tissue loss may drive restoration of energy balance.
www.clinicaltrials.gov #NCT01603550.
军事人员经常经历间歇性的严重能量不足，这可能会损害健康和表现。导致能量摄入不足以及随后暴饮暴食冲动的生理因素尚未完全明确。本研究旨在确定在严重短期能量剥夺期间及之后食欲、代谢稳态和内分泌反应之间的关联。
23名年轻成年人（17名男性/6名女性，21±3岁，BMI 25±3kg/m²）参与了一项随机、对照、交叉试验。在单独的48小时期间，参与者通过在40 - 65% VO₂峰值下进行规定运动，使日常能量消耗增加1647±345千卡/天（平均值±标准差），并食用提供的等容量饮食，这些饮食旨在在能量消耗增加时维持能量平衡（能量平衡组，EB；36±93千卡/天能量不足）或产生严重能量不足（能量不足组，ED；3681±716千卡/天能量不足）。定期测量食欲、代谢稳态标志物以及食欲和底物可用性的内分泌介质。在两个实验期之后的36小时内测量自由能量摄入量。
在能量不足期间食欲增加，尽管饮食量保持不变，但仍大于能量平衡组（P = 0.004）。与能量平衡组之后相比，能量不足组之后的自由能量摄入量高出907千卡/36小时[95%置信区间：321, 1493千卡/36小时，P = 0.004]。与能量平衡组相比，能量不足组期间血清β-羟基丁酸、游离脂肪酸、支链氨基酸、硫酸脱氢表雄酮（DHEA - S）和皮质醇浓度更高（所有P < 0.001），而全身蛋白质平衡更负（P < 0.001），血清葡萄糖、胰岛素和瘦素浓度更低（所有P < 0.001）。在能量平衡组期间，皮质醇浓度而非任何其他激素或代谢底物与饱腹感呈负相关（R² = 0.23，P = 0.04）。相比之下，在能量不足组期间血清葡萄糖和DHEA - S浓度与饱腹感呈负相关（R² = 0.68，P < 0.001）。未观察到能量平衡组期间测量的生理变量与能量平衡组之后的自由能量摄入量之间的关联。然而，能量不足组期间测量的血清瘦素和净蛋白质平衡与能量不足组之后的自由能量摄入量呈负相关（R² = 0.48，P = 0.01）。
这些发现表明，能量剥夺期间代谢稳态的变化独立于饮食量的减少来调节食欲。能量剥夺后，脂肪和瘦组织损失的生理信号可能驱动能量平衡的恢复。
www.clinicaltrials.gov #NCT01603550
