Hu Mingzhu, Shi Qingde, Sun Shengyan, Hong Hin Ieong, Zhang Haifeng, Qi Fengxue, Zou Liye, Nie Jinlei
Faculty of Education, University of Macau, Macao, Macao SAR, China.
Faculty of Health Sciences and Sports, Macao Polytechnic University, Macao, Macao SAR, China.
Front Nutr. 2022 Jul 6;9:894916. doi: 10.3389/fnut.2022.894916. eCollection 2022.
The effectiveness of low-carbohydrate diets (LCDs) on weight loss and exercise for improving cardiometabolic fitness have been well documented in the literature, but the effects of LCDs and whether adding exercise to a LCD regime could additionally benefit mental health (e. g., by lowering the level of anxiety) and associated changes in eating behavior are less clear in overweight and obese populations. Therefore, this study aimed to investigate the effects of a 4-week LCD with or without exercise on anxiety and eating behavior, and to explore the associations between changes in the psychological state and physiological parameters (i.e., body composition, aerobic fitness, blood pressure, lipid profile, and metabolic hormones).
Seventy-four overweight Chinese women [age: 20.8 ± 3.0 years, body mass index (BMI): 25.3 ± 3.3 kg·m] completed the 4-week randomized controlled trial, which included a LCD group (i.e., ~50 g daily carbohydrate intake) with exercise training 5 days/week (LC-EXE, = 26), a LCD group without exercise training (LC-CON, = 25) and a control group that did not modify their habitual diets and physical activity (CON, = 23). Levels of anxiety, eating behavior scores and physiological parameters (i.e., body weight, V̇O, blood pressure, fasting glucose, blood lipids, and serum metabolic hormones including insulin, C-peptide, leptin, and ghrelin) were measured before and after the intervention.
There were significant reductions in anxiety levels in the LC-EXE compared with the LC-CON group, while no statistical changes were found in eating behaviors in any conditions after the 4-week intervention. Significant reduction in weight (3.0 kg or 4%, < 0.01) and decreases in insulin (30% < 0.01), C-peptide (20% < 0.01), and leptin (40%, < 0.01) were found in both LC-CON and LC-EXE groups, but adding exercise to a LCD regime generated no additional effects. There were significant improvements in V̇O (15% < 0.01) and anxiety (25% < 0.01) in the LC-EXE compared with the LC-CON group, while no statistical differences were found between CON and LC-CON treatments. Further analysis revealed a negative association ( = -0.32, < 0.01) between changes in levels of anxiety and changes in V̇O in all participates, no other correlations were found between changes in psychological and physiological parameters.
Although the combination of a LCD and exercise may not induce additional reductions in body weight in overweight young females, exercise could be a useful add-on treatment along with a LCD to improve cardiometabolic health and lower anxiety levels.
低碳水化合物饮食（LCDs）对减肥的有效性以及运动对改善心脏代谢健康的作用在文献中已有充分记载，但在超重和肥胖人群中，低碳水化合物饮食的效果以及在低碳水化合物饮食方案中加入运动是否能额外有益于心理健康（如降低焦虑水平）和相关饮食行为变化尚不清楚。因此，本研究旨在调查为期4周的有或无运动的低碳水化合物饮食对焦虑和饮食行为的影响，并探讨心理状态变化与生理参数（即身体成分、有氧适能、血压、血脂和代谢激素）之间的关联。
74名超重中国女性[年龄：20.8±3.0岁，体重指数（BMI）：25.3±3.3kg·m²]完成了为期4周的随机对照试验，该试验包括一个每天碳水化合物摄入量约50g且每周进行5天运动训练的低碳水化合物饮食组（LC-EXE，n = 26）、一个无运动训练的低碳水化合物饮食组（LC-CON，n = 25）和一个未改变其习惯饮食和身体活动的对照组（CON，n = 23）。在干预前后测量焦虑水平、饮食行为评分和生理参数（即体重、摄氧量、血压、空腹血糖、血脂以及包括胰岛素、C肽、瘦素和胃饥饿素在内的血清代谢激素）。
与LC-CON组相比，LC-EXE组的焦虑水平显著降低，而在4周干预后，任何情况下的饮食行为均未发现统计学变化。LC-CON组和LC-EXE组的体重均显著降低（约3.0kg或4%，P<0.01），胰岛素（约30%，P<0.01）、C肽（约20%，P<0.01）和瘦素（约40%，P<0.01）均下降，但在低碳水化合物饮食方案中加入运动未产生额外效果。与LC-CON组相比，LC-EXE组的摄氧量（约15%，P<0.01）和焦虑（约25%，P<0.01）有显著改善，而CON组和LC-CON组治疗之间未发现统计学差异。进一步分析显示，所有参与者的焦虑水平变化与摄氧量变化之间存在负相关（r = -0.32，P<0.01），心理和生理参数变化之间未发现其他相关性。
虽然低碳水化合物饮食与运动相结合可能不会使超重年轻女性的体重进一步降低，但运动作为低碳水化合物饮食的辅助治疗手段，可改善心脏代谢健康并降低焦虑水平。
