Biyikoglu Hayriye, Robertson M Denise, Collins Adam L
Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Surrey, GU2 7XH, UK.
School of Life and Health Sciences, University of Roehampton, London, SW15 5PH, UK.
Eur J Nutr. 2025 Mar 20;64(3):133. doi: 10.1007/s00394-025-03646-5.
Low-carbohydrate diets and intermittent energy restriction may offer metabolic advantages in fuel utilisation, that are independent of weight loss. The underlying mechanisms for these effects are unclear but may involve extensions of the catabolic phase and/or attenuation of insulin secretion. To address this gap, we aimed to investigate the independent acute metabolic effect of carbohydrate restriction at varying energy levels. Twelve, (six female) healthy overweight/obese participants (27.3 ± 1.8 years; 25.2 ± 1.6 kg/m) completed this three-way study. Volunteers followed three diets for one day (36 h, covering the intervention day and overnight fasting), separated by 5-day washout: a normal carbohydrate, energy-balanced diet (nEB, 55% CHO), a low-carbohydrate, energy-balanced diet (LCEB, 50 g/day CHO), and a low-carbohydrate, energy-restricted diet (LC25, 50 g/day CHO with 75% energy restriction). Fasting and serial postprandial (360 min) measurements to a mixed test meal were collected the following morning. Additionally, subjective appetite responses and two-day subsequent ad libitum food intake was assessed. Both low-carbohydrate with and without energy restriction diets induced comparable decrease in triacylglycerol iAUC (p = 0.02, p = 0.04, respectively), and respiratory quotient (both p < 0.01) along with increase in non-esterified fatty acids (both p < 0.01) and 3-hydroxybutyrate (p = 0.001, p = 0.01, respectively) levels. Compared to a non-restricted carbohydrate, energy-balanced diet, postprandial glucose levels significantly increased in the LCEB arm (p = 0.024) and showed a rising trend in the LC25 arm (p = 0.07). Neither insulin responses nor resting, and diet-induced thermogenesis were significantly altered by variations in energy or carbohydrate content. These findings demonstrate that carbohydrate restriction, without altering energy intake, can elicit effects similar to those observed in short-term fasting. As such we propose a strategy of repeated carbohydrate restriction cycles alone may be an emerging alternative approach for the enhancement of cardiometabolic health, warranting further investigation.
低碳水化合物饮食和间歇性能量限制可能在燃料利用方面提供代谢优势，且这些优势独立于体重减轻。这些效应的潜在机制尚不清楚，但可能涉及分解代谢阶段的延长和/或胰岛素分泌的减弱。为了填补这一空白，我们旨在研究不同能量水平下碳水化合物限制的独立急性代谢效应。12名（6名女性）健康超重/肥胖参与者（27.3±1.8岁；25.2±1.6kg/m²）完成了这项三因素研究。志愿者遵循三种饮食方案各一天（36小时，涵盖干预日和夜间禁食），中间间隔5天的洗脱期：正常碳水化合物、能量平衡饮食（nEB，55%碳水化合物）、低碳水化合物、能量平衡饮食（LCEB，50克/天碳水化合物）和低碳水化合物、能量限制饮食（LC25，50克/天碳水化合物且能量限制75%）。第二天早上收集空腹和对混合测试餐的连续餐后（360分钟）测量数据。此外，评估主观食欲反应和随后两天的随意食物摄入量。有能量限制和无能量限制的低碳水化合物饮食均导致三酰甘油iAUC（分别为p = 0.02，p = 0.04）和呼吸商（均为p < 0.01）显著降低，同时非酯化脂肪酸（均为p < 0.01）和3-羟基丁酸水平升高（分别为p = 0.001，p = 0.01）。与非限制碳水化合物的能量平衡饮食相比，LCEB组餐后血糖水平显著升高（p = 0.024），LC25组呈上升趋势（p = 0.07）。能量或碳水化合物含量的变化均未显著改变胰岛素反应、静息代谢率和饮食诱导的产热。这些发现表明，在不改变能量摄入的情况下，碳水化合物限制可引发与短期禁食类似的效应。因此，我们提出仅重复碳水化合物限制周期的策略可能是一种新兴的改善心脏代谢健康的替代方法，值得进一步研究。
