Sciarrillo Christina M, Guo Juen, Hengist Aaron, Darcey Valerie L, Hall Kevin D
National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, United States.
National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, United States.
Am J Clin Nutr. 2024 Oct;120(4):953-963. doi: 10.1016/j.ajcnut.2024.08.013. Epub 2024 Aug 18.
Crossover studies can induce order effects, especially when they lack a washout period.
We performed secondary analyses comparing groups of subjects randomly assigned to different diet orders in 2 inpatient crossover studies originally designed to compare within-subject differences in ad libitum energy intake. One study compared minimally processed low-carbohydrate (LC) compared with low-fat (LF) diets, and the other matched macronutrients and compared minimally processed food (MPF) with ultraprocessed food (UPF) diets.
Diet order group comparisons of changes in body weight and body composition, and differences in energy expenditure and food intake were assessed over 4 wk in 20 adults randomly assigned to either the LC followed immediately by the LF diet (LC → LF) or the opposite order (LF → LC), and 20 adults randomly assigned to either the MPF followed by the UPF (MPF → UPF) diets or the opposite order (UPF → MPF).
Subjects randomly assigned to LC → LF lost 2.9 ± 1.1 kg more body weight (P <0.001) and 1.5 ± 0.6 kg more body fat (P = 0.03) than the LF → LC group, likely because the LC → LF group consumed 921 ± 304 kcal/d less than the LF → LC group (P = 0.003). These energy intake differences were driven by the last 2 wk (-1610 ± 312 kcal/d; P < 0.0001), perhaps because of carryover effects of gut adaptations during the first 2 wk arising from large differences in the mass of food (1296 ± 215 g/d; P <0.00001) and fiber consumed (58 ± 6 g/d; P <0.00001). There were no significant diet order effects on energy intake, body weight, or body composition changes between UPF → MPF and MPF → UPF groups.
Diet order significantly affected energy intake, body weight, and body fat in a 4-wk crossover inpatient diet study varying in macronutrients, but not in a similarly structured study varying in ultraprocessed foods. This trial was registered at clinicaltrials.gov as NCT03407053 and NCT03878108.
交叉研究可能会产生顺序效应，尤其是在缺乏洗脱期的情况下。
在两项住院患者交叉研究中，我们进行了二次分析，比较随机分配到不同饮食顺序的受试者组。这两项研究最初旨在比较自由能量摄入量的个体内差异。一项研究比较了最低加工的低碳水化合物（LC）饮食与低脂（LF）饮食，另一项研究匹配了宏量营养素，并比较了最低加工食品（MPF）与超加工食品（UPF）饮食。
在20名随机分配为立即从LC饮食改为LF饮食（LC→LF）或相反顺序（LF→LC）的成年人，以及20名随机分配为从MPF饮食改为UPF饮食（MPF→UPF）或相反顺序（UPF→MPF）的成年人中，评估了4周内饮食顺序组在体重和身体成分变化、能量消耗和食物摄入量差异方面的情况。
随机分配到LC→LF组的受试者比LF→LC组多减重2.9±1.1kg（P<0.001），多减体脂1.5±0.6kg（P=0.03），这可能是因为LC→LF组比LF→LC组每天少摄入921±304千卡（P=0.003）。这些能量摄入差异在前两周（-1610±312千卡/天；P<0.0001）的基础上，由最后两周驱动，这可能是由于前两周肠道适应的遗留效应，这是由于食物摄入量（1296±215克/天；P<0.00001）和膳食纤维摄入量（58±6克/天；P<0.00001）存在巨大差异所致。在UPF→MPF组和MPF→UPF组之间，饮食顺序对能量摄入、体重或身体成分变化没有显著影响。
在一项为期4周的交叉住院饮食研究中，饮食顺序对宏量营养素不同的饮食中能量摄入、体重和体脂有显著影响，但在一项结构类似、超加工食品不同的研究中则没有。本试验已在clinicaltrials.gov上注册，注册号为NCT03407053和NCT03878108。
