Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ.
Am J Clin Nutr. 2019 Sep 1;110(3):593-604. doi: 10.1093/ajcn/nqz062.
Greater increase in 24-h energy expenditure (24EE) during overfeeding and smaller decrease in 24EE during fasting ("spendthrift" metabolic phenotype) are associated with more weight loss during sustained caloric restriction in overweight subjects.
The aim of this study was to investigate whether these acute metabolic responses can also predict weight gain during sustained overfeeding in lean individuals.
Seven lean men participated in this study. Prior to overfeeding, 24EE responses to fasting and 200% normal-protein overfeeding were measured in a whole-room indirect calorimeter. Volunteers underwent 6 wk of 150% low-protein (2%) overfeeding followed by another wk of weight-maintaining diet, during which 24EE was revaluated. Body composition, 24EE, and various hormone concentrations, including fibroblast growth factor 21 (FGF21), were assessed at baseline, at wk 1, 3, and 6 of the overfeeding period, and 1 wk following overfeeding through the use of dual-energy X-ray absorptiometry, indirect calorimetry, and ELISA. Cumulative energy surplus was calculated from 24EE, daily physical activity, and direct measurements of calories of nutrient intake, feces, and urine by bomb calorimetry.
The average weight gain during 6 wk of low-protein overfeeding was 3.8 kg (6.1%, min: +2.5%, max: +8.0%). During 24-h fasting at baseline, 24EE decreased on average (mean ± SD) by 158 ± 81 kcal/d (P = 0.007). Subjects with less 24EE decrease during fasting (more metabolically spendthrift individuals) gained less weight (r = -0.84, P = 0.03), less fat mass (r = -0.81, P = 0.049), and stored less calories (r = -0.91, P = 0.03) during overfeeding. Following overfeeding, increased 24EE above requirements for achieved body size was associated with less weight and fat mass gain (r = -0.78, P = 0.04) and with the increase in 24EE during 200% normal-protein overfeeding measured at baseline (r = 0.91, P = 0.005). Serum FGF21 concentrations increased up to 44-fold during overfeeding (P < 0.0001).
Low-protein overfeeding may be an important tool to identify metabolic phenotypes (spendthrift compared with thrifty) that characterize susceptibility to weight gain. This trial was registered at clinicaltrials.gov as NCT00687115.
超重受试者在持续热量限制期间，过量进食时 24 小时能量消耗（24EE）增加更多，禁食时 24EE 减少更少（“挥霍”代谢表型），与体重减轻更多相关。
本研究旨在探讨这些急性代谢反应是否也可以预测瘦人在持续过量进食期间的体重增加。
7 名瘦人参加了这项研究。在整个房间间接测热仪中测量了空腹和 200%正常蛋白质过量进食期间的 24EE 反应，然后进行了 6 周的 150%低蛋白（2%）过量进食，随后进行了 1 周的维持体重饮食，在此期间重新评估了 24EE。在过量进食期间的第 1、3 和 6 周以及过量进食后 1 周，使用双能 X 射线吸收仪、间接测热法和酶联免疫吸附试验评估身体成分、24EE 和各种激素浓度，包括成纤维细胞生长因子 21（FGF21）。通过弹式热量计从 24EE、日常体力活动以及营养素摄入、粪便和尿液的直接热量测量中计算出累计能量过剩。
6 周低蛋白过量进食期间的平均体重增加为 3.8 公斤（6.1%，最小值：+2.5%，最大值：+8.0%）。在基线时的 24 小时禁食期间，24EE 平均下降（平均 ± SD）158 ± 81 kcal/d（P = 0.007）。在禁食期间 24EE 下降较少（代谢挥霍更多的个体）的受试者体重增加较少（r = -0.84，P = 0.03），脂肪量减少较少（r = -0.81，P = 0.049），并且在过量进食期间储存的卡路里减少较少（r = -0.91，P = 0.03）。过量进食后，24EE 增加超过实现身体大小所需的量与体重和脂肪量增加减少（r = -0.78，P = 0.04）以及在基线时测量的 200%正常蛋白质过量进食期间 24EE 的增加相关（r = 0.91，P = 0.005）。血清 FGF21 浓度在过量进食期间增加了 44 倍（P < 0.0001）。
低蛋白过量进食可能是一种重要的工具，可以识别出代谢表型（挥霍型与节俭型），这些表型可表征体重增加的易感性。这项试验在 clinicaltrials.gov 上注册为 NCT00687115。
