Gardner Christopher D, Trepanowski John F, Del Gobbo Liana C, Hauser Michelle E, Rigdon Joseph, Ioannidis John P A, Desai Manisha, King Abby C
Stanford Prevention Research Center, Department of Medicine, Stanford University Medical School, Stanford, California.
Quantitative Sciences Unit, Stanford University School of Medicine, Stanford, California.
JAMA. 2018 Feb 20;319(7):667-679. doi: 10.1001/jama.2018.0245.
Dietary modification remains key to successful weight loss. Yet, no one dietary strategy is consistently superior to others for the general population. Previous research suggests genotype or insulin-glucose dynamics may modify the effects of diets.
To determine the effect of a healthy low-fat (HLF) diet vs a healthy low-carbohydrate (HLC) diet on weight change and if genotype pattern or insulin secretion are related to the dietary effects on weight loss.
DESIGN, SETTING, AND PARTICIPANTS: The Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) randomized clinical trial included 609 adults aged 18 to 50 years without diabetes with a body mass index between 28 and 40. The trial enrollment was from January 29, 2013, through April 14, 2015; the date of final follow-up was May 16, 2016. Participants were randomized to the 12-month HLF or HLC diet. The study also tested whether 3 single-nucleotide polymorphism multilocus genotype responsiveness patterns or insulin secretion (INS-30; blood concentration of insulin 30 minutes after a glucose challenge) were associated with weight loss.
Health educators delivered the behavior modification intervention to HLF (n = 305) and HLC (n = 304) participants via 22 diet-specific small group sessions administered over 12 months. The sessions focused on ways to achieve the lowest fat or carbohydrate intake that could be maintained long-term and emphasized diet quality.
Primary outcome was 12-month weight change and determination of whether there were significant interactions among diet type and genotype pattern, diet and insulin secretion, and diet and weight loss.
Among 609 participants randomized (mean age, 40 [SD, 7] years; 57% women; mean body mass index, 33 [SD, 3]; 244 [40%] had a low-fat genotype; 180 [30%] had a low-carbohydrate genotype; mean baseline INS-30, 93 μIU/mL), 481 (79%) completed the trial. In the HLF vs HLC diets, respectively, the mean 12-month macronutrient distributions were 48% vs 30% for carbohydrates, 29% vs 45% for fat, and 21% vs 23% for protein. Weight change at 12 months was -5.3 kg for the HLF diet vs -6.0 kg for the HLC diet (mean between-group difference, 0.7 kg [95% CI, -0.2 to 1.6 kg]). There was no significant diet-genotype pattern interaction (P = .20) or diet-insulin secretion (INS-30) interaction (P = .47) with 12-month weight loss. There were 18 adverse events or serious adverse events that were evenly distributed across the 2 diet groups.
In this 12-month weight loss diet study, there was no significant difference in weight change between a healthy low-fat diet vs a healthy low-carbohydrate diet, and neither genotype pattern nor baseline insulin secretion was associated with the dietary effects on weight loss. In the context of these 2 common weight loss diet approaches, neither of the 2 hypothesized predisposing factors was helpful in identifying which diet was better for whom.
clinicaltrials.gov Identifier: NCT01826591.
饮食调整仍然是成功减肥的关键。然而，对于普通人群而言，没有一种饮食策略始终优于其他策略。先前的研究表明，基因型或胰岛素 - 葡萄糖动态变化可能会改变饮食的效果。
确定健康低脂（HLF）饮食与健康低碳水化合物（HLC）饮食对体重变化的影响，以及基因型模式或胰岛素分泌是否与饮食对减肥的影响相关。
设计、地点和参与者：饮食干预研究治疗成功相关因素（DIETFITS）随机临床试验纳入了609名年龄在18至50岁之间、无糖尿病且体重指数在28至40之间的成年人。试验入组时间为2013年1月29日至2015年4月14日；最终随访日期为2016年5月16日。参与者被随机分配到12个月的HLF或HLC饮食组。该研究还测试了3种单核苷酸多态性多位点基因型反应模式或胰岛素分泌（INS - 30；葡萄糖激发后30分钟的胰岛素血浓度）是否与体重减轻相关。
健康教育工作者通过在12个月内进行的22次特定饮食小组会议，对HLF组（n = 305）和HLC组（n = 304）的参与者进行行为改变干预。会议重点关注实现可长期维持的最低脂肪或碳水化合物摄入量的方法，并强调饮食质量。
主要结局是12个月时的体重变化，以及确定饮食类型与基因型模式、饮食与胰岛素分泌、饮食与体重减轻之间是否存在显著相互作用。
在随机分组的609名参与者中（平均年龄40[标准差，7]岁；57%为女性；平均体重指数33[标准差，3]；244名[40%]具有低脂基因型；180名[30%]具有低碳水化合物基因型；平均基线INS - 30为93μIU/mL），481名（79%）完成了试验。在HLF饮食组与HLC饮食组中，12个月时的平均宏量营养素分布分别为：碳水化合物48%对30%，脂肪29%对45%，蛋白质21%对23%。HLF饮食组12个月时的体重变化为 - 5.3kg，HLC饮食组为 - 6.0kg（组间平均差异为0.7kg[95%CI， - 0.2至1.6kg]）。在12个月体重减轻方面，饮食与基因型模式之间无显著相互作用（P = 0.20），饮食与胰岛素分泌（INS - 30）之间也无显著相互作用（P = 0.47）。共有18起不良事件或严重不良事件，在两个饮食组中分布均匀。
在这项为期12个月的减肥饮食研究中，健康低脂饮食与健康低碳水化合物饮食在体重变化方面无显著差异，基因型模式和基线胰岛素分泌均与饮食对体重减轻的影响无关。在这两种常见的减肥饮食方法中，这两种假设的 predisposing 因素均无助于确定哪种饮食对谁更有益。
clinicaltrials.gov标识符：NCT01826591。
