A recent study found that our bodies burn more energy when we restrict our eating to certain times of the day.
Weight Gain and Obesity
Obesity and weight gain is a consequence of eating a high calorie diet. But, the health effect of diet depends, to a certain extent, on when during the day we choose to consume our meals.
Eating when you’re normally inactive – at nighttime for example – makes you more susceptible of becoming obese. Though not fully understood why this happens, researchers derive that obesity results in part from a variance between meal timing and the natural day-night cycle, or circadian rhythm.
A National Institutes of Health-funded research team led by Dr. Joseph Bass at Northwestern University studied the metabolic effects of a high fat diet in mice when feeding was restricted to either daytime or nighttime.
Circadian Rhythms Influence Creatine Metabolism
Mice are nocturnal. They usually eat at night. Additionally, mice have higher levels of a nutrient called creatine in their fat cells. Creatine stores excess energy during times of low energy demand and releases it to power the cell during times of high demand. But, creatine can also release its stored energy as heat in a process known as a futile creatine cycle.
The research team wanted to test whether creatine was behind the effect of feeding time on weight gain. So, they studied the effect of time-restricted feeding in mice engineered to be creatine-deficient. In these mice, eating only at night did not reduce weight gain or increase energy expenditure compared to daytime eating.
These results suggest that, because of nighttime feeding, more heat was produced from the energy stored in creatine…raising the amount of total energy use and reducing weight gain in the mice.
In addition, the results suggest that circadian rhythms influence creatine metabolism.
Gaining Less Weight on a High-Fat Diet
To test this idea, the researchers engineered mice with increased activity in genes that control circadian rhythms. These mice actually gained less weight on a high-fat diet…in addition to using more oxygen than the control mice. They also had increased futile creatine cycling and better glucose tolerance.
High-fat diets are noted for suppressing genes involved in circadian rhythms — predominantly in fat tissue.
These latest findings give further understanding into the connections between diet, metabolism, and the body’s circadian clock. They also present a clarification for the benefits of time-restricted feeding.
Dr. Bass briefly explains,
“The clock is sensitive to the time people eat, especially in fat tissue, and that sensitivity is thrown off by high-fat diets. We still don’t understand why that is, but what we do know is that as animals become obese, they start to eat more when they should be asleep. This research shows why that matters.”
The results of this study appeared in Science on October 20, 2022.