Timing of meals may influence weight gain
MedWire News: Results from a study carried out in mice suggest that the timing of meals may be just as important as the amount of calories consumed for regulating bodyweight.
The authors found that mice who were only allowed access to food for 8 hours were less likely to become obese than those who had 24-hour access, regardless of calorie intake.
Satchidananda Panda (Salk Institute for Biological Studies, La Jolla, California, USA) and colleagues explain that diet-induced obesity in mice has previously been attributed solely to excessive fat intake.
However, they add that animals given 24-hour, ad libitum access to food tend to eat continually, disrupting their normal feeding cycles.
To assess whether disruption of the metabolic cycle could influence weight gain, the team compared mice allowed restricted access to food during 8 hours of "darkness" and mice allowed ad libitum access to food for more than 100 days. The two groups were further divided into mice given normal food (average fat content) and those given high-fat food.
The researchers found that mice with ad libitum access to high-fat food developed obesity, diabetes, and the metabolic syndrome. However, mice with restricted access to high-fat food did not become obese despite consuming a similar amount of calories to the mice given ad libitum access to high-fat food. Neither group of mice given normal food became obese.
The mice with restricted access to high-fat food showed increased thermogenesis and improved nutrient utilization rhythms compared with the mice who had ad libitum access, which the researchers believe explains the lower levels of adiposity and liver steatosis in this group. The mice with restricted food access also had normal glucose tolerance, reduced serum cholesterol, increased production of bile acid, and improved motor function compared with the ad libitum mice.
Mice who were exposed to restricted feeding also had improved pathway function for the metabolic regulators cAMP response element-binding protein (CREB), mammalian target of rapamycin (mTOR), and AMP-activated protein kinase (AMPK) and oscillations of the circadian clock. Disruptions in these pathways have been linked to metabolic disease.
"Current public health surveys on human nutrition focus on the quality of nutrition and quantity of food consumption with no evidence-based method in place to monitor temporal pattern of food intake," write the authors in Cell Metabolism.
"More studies are necessary to define the relationship between temporal eating and obesity in humans," they add. "The results presented in our study with mice suggest that restricted feeding could be a nonpharmacological intervention in humans that could prevent obesity and its associated metabolic disorders."
By Helen Albert