重新分析饮食干预检验治疗成功的因素试验（DIETFITS）发现碳水化合物-胰岛素模型的证据。

Evidence for the carbohydrate-insulin model in a reanalysis of the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) trial.

机构信息

Metabolic Diseases Research Unit, National Institute for Medical Sciences and Nutrition Salvador Zubiran, Tlalpan, Mexico City, Mexico; Monterrey Institute of Technology and Higher Education, Xochimilco, Mexico City, Mexico.

Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, MN, USA.

出版信息

Am J Clin Nutr. 2023 Mar;117(3):599-606. doi: 10.1016/j.ajcnut.2022.12.014. Epub 2023 Jan 6.

DOI:10.1016/j.ajcnut.2022.12.014

PMID:36811468

Abstract

BACKGROUND

The Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) trial demonstrated that meaningful weight loss can be achieved with either a "healthy low-carbohydrate diet" (LCD) or "healthy low-fat diet" (LFD). However, because both diets substantially decreased glycemic load (GL), the dietary factors mediating weight loss remain unclear.

OBJECTIVES

We aimed to explore the contribution of macronutrients and GL to weight loss in DIETFITS and examine a hypothesized relationship between GL and insulin secretion.

DESIGN

This study is a secondary data analysis of the DIETFITS trial, in which participants with overweight or obesity (aged 18-50 y) were randomized to a 12-mo LCD (N = 304) or LFD (N = 305).

RESULTS

Measures related to carbohydrate intake (total amount, glycemic index, added sugar, and fiber) showed strong associations with weight loss at 3-, 6-, and 12-mo time points in the full cohort, whereas those related to total fat intake showed weak to no associations. A biomarker of carbohydrate (triglyceride/HDL cholesterol ratio) predicted weight loss at all time points (3-mo: β [kg/biomarker z-score change] = 1.1, P = 3.5 × 10; 6-mo: β = 1.7, P = 1.1 × 10; and 12-mo: β = 2.6, P = 1.5 × 10), whereas that of fat (low-density lipoprotein cholesterol + HDL cholesterol) did not (all time points: P = NS). In a mediation model, GL explained most of the observed effect of total calorie intake on weight change. Dividing the cohort into quintiles of baseline insulin secretion and GL reduction revealed evidence of effect modification for weight loss, with P = 0.0009 at 3 mo, P = 0.01 at 6 mo, and P = 0.07 at 12 mo.

CONCLUSIONS

As predicted by the carbohydrate-insulin model of obesity, weight loss in both diet groups of DIETFITS seems to have been driven by the reduction of GL more so than dietary fat or calories, an effect that may be most pronounced among those with high insulin secretion. These findings should be interpreted cautiously in view of the exploratory nature of this study.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01826591).

摘要

背景

饮食干预检验治疗成功的相互作用因素（DIETFITS）试验表明，通过“健康低碳水化合物饮食”（LCD）或“健康低脂肪饮食”（LFD）都可以实现有意义的体重减轻。然而，由于这两种饮食都大大降低了血糖负荷（GL），介导体重减轻的饮食因素仍不清楚。

目的

我们旨在探讨 DIETFITS 中宏量营养素和 GL 对体重减轻的贡献，并检验 GL 与胰岛素分泌之间的假设关系。

设计

这是 DIETFITS 试验的二次数据分析，其中超重或肥胖的参与者（年龄 18-50 岁）被随机分配到 12 个月的 LCD（N = 304）或 LFD（N = 305）组。

结果

在整个队列中，与碳水化合物摄入量相关的测量指标（总量、血糖指数、添加糖和纤维）在 3、6 和 12 个月的时间点与体重减轻呈强相关，而与总脂肪摄入量相关的测量指标呈弱相关或无相关性。碳水化合物的生物标志物（甘油三酯/高密度脂蛋白胆固醇比值）预测了所有时间点的体重减轻（3 个月：β[每生物标志物 z 分数变化的公斤数] = 1.1，P = 3.5×10；6 个月：β = 1.7，P = 1.1×10；12 个月：β = 2.6，P = 1.5×10），而脂肪的生物标志物（低密度脂蛋白胆固醇+高密度脂蛋白胆固醇）则没有（所有时间点：P = NS）。在一个中介模型中，GL 解释了总卡路里摄入量对体重变化的大部分观察到的影响。根据基线胰岛素分泌和 GL 降低将队列分为五分位数，结果显示体重减轻存在效应修饰，3 个月时 P = 0.0009，6 个月时 P = 0.01，12 个月时 P = 0.07。