Weight loss can be impacted more by the time of day that you eat than the amount of calories you consume, a new study on mice suggests.
A team of researchers from the University of Texas Southwestern Medical Centre conducted the investigation, looking at why calorie-restricted diets improve longevity.
The scientists used a newly developed “high-precision feeding system”, which made use of high-tech sensors and automated feeding equipment and ensured the mice were not disrupted from their sleep.
The mice were divided into five groups, following certain diets and feeding regimes. Some mice could eat as much as they wanted across a 12-hour day or night period, while other mice had a limit on the amount of food they could eat, as well as facing differing time restrictions.
It was discovered that the only mice which experienced weight loss were the ones which followed a reduced-calorie diet plan and ate only during their normal feeding/active cycle.
This was despite eating exactly the same amount of food as another group of mice, which were fed during their rest time in daylight (mice are normally awake at night).
Two groups of mice that had been fed during their normal daytime rest cycle remained active at night, which suggests that they experienced chronic sleep deprivation. The researchers believe this supported the concept that when we eat affects our circadian rhythm, which may impact our lifespan.
“Translated into human behaviour, these studies suggest that dieting will only be effective if calories are consumed during the daytime when we are awake and active,” said the study’s lead author, Dr Joseph Takahashi.
“They further suggest that eating at the wrong time at night will not lead to weight loss even when dieting.
“It has been known for decades that calorie restriction prolongs lifespan in animals, but these types of studies are very difficult to conduct because they required manual feeding of subjects over many years.
“Despite the importance of these factors, manipulating when and how much food is available for extended periods has been difficult in past research.”
The study was published in the journal Cell Metabolism.