National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, USA.
National Institute on Drug Abuse, Baltimore, Maryland, USA.
Obesity (Silver Spring). 2018 Jun;26(6):1026-1033. doi: 10.1002/oby.22195. Epub 2018 Apr 29.
Ad libitum high-fat diets (HFDs) spontaneously increase caloric intake in rodents, which correlates positively with weight gain. However, it remains unclear why rodents overeat HFDs. This paper investigated how changing the proportion of diet that came from HFDs might alter daily caloric intake in mice.
Mice were given 25%, 50%, or 90% of their daily caloric need from an HFD, along with ad libitum access to a low-fat rodent chow diet. Food intake was measured daily to determine how these HFD supplements impacted total daily caloric intake. Follow-up experiments addressed the timing of HFD feeding.
HFD supplements did not alter total caloric intake or body weight. In a follow-up experiment, mice consumed approximately 50% of their daily caloric need from an HFD in 30 minutes during the light cycle, a time when mice do not normally consume food.
An HFD did not disrupt regulation of total daily caloric intake, even when up to 90% of total calories came from the HFD. However, HFDs increased daily caloric intake when provided ad libitum and were readily consumed by mice outside of their normal feeding cycle. Ad libitum HFDs appear to induce overconsumption beyond the mechanisms that regulate daily caloric intake.
随意给予高脂肪饮食（HFD）会自发增加啮齿动物的热量摄入，这与体重增加呈正相关。然而，目前尚不清楚为什么啮齿动物会过量食用 HFD。本文研究了改变 HFD 的饮食比例如何改变小鼠的每日热量摄入。
小鼠从 HFD 中获得其每日热量需求的 25%、50%或 90%，同时随意获得低脂啮齿动物饲料。每日测量食物摄入量，以确定这些 HFD 补充剂如何影响总日热量摄入。后续实验解决了 HFD 喂养的时间问题。
HFD 补充剂并未改变总热量摄入或体重。在后续实验中，小鼠在光照周期内的 30 分钟内消耗了大约 50%的 HFD 日热量需求，而此时小鼠通常不进食。
即使高达 90%的总热量来自 HFD，HFD 也不会破坏总日热量摄入的调节。然而，随意给予 HFD 会增加每日热量摄入，并且很容易被小鼠在正常进食周期之外消耗。随意的 HFD 似乎会导致过度摄入，超出了调节每日热量摄入的机制。
