Reverse Obesity with Time-Restricted Eating

Did You Know…that what you eat may be less important than when you eat?

Obesity threatens every aspect of personal health for whom it affects, and as the epidemic continues, its associated expenses also threaten to crush our nation’s healthcare system.

Typically, advice on reversing obesity focuses on dietary choices.  But what if when you eat is just as important as what you eat—or even more important? Groundbreaking new research from the Salk Institute suggests that this may very well be true!  The timing of meals and snacks may influence weight control more than the number of calories you consume.

The research suggests that restricting caloric consumption to an 8- to 12-hour period (which most people did just a century ago) could even prevent and reverse high cholesterol, diabetes, and obesity.

What is “Time-Restricted” Eating? 

With our modern lifestyles, humans have adapted to a nearly around-the-clock eating schedule that includes highly caloric late-night snacks.  Time-restricted eating simply means defining and adhering to a specific period of eating during the day, and not eating for the rest of the day.

Time-restricted eating hasn’t been studied in humans yet, but researchers at the Salk institute have been testing the method in mice and the results were extremely impressive.

  • Mice fed during an 8 -12 hour period stayed healthier and slimmer, even when they were fed a high-fat diet.
  • Mice who ate only during a specified 8-hour period reversed obesity and diabetes.
  • Mice fed the same diet but allowed to eat any time of day or night fared much worse.

Impressive Benefits Under Varying Conditions 

Researchers from Salk assigned nearly 400 mice (some normal weight and some obese), to various diets and eating time restrictions.

Mice limited to a 9 to 12-hour eating period gained less weight than mice allowed to eat without time restriction—in spite of the fact that both groups of mice took in the same number of calories.  Further, the time-restricted mice gained more lean muscle mass than the other mice.

The benefits of time-restricted feeding held true regardless of:

  • Mouse weight
  • Diet type
  • Length of time restriction (to a degree)

Different lengths of the eating period—9, 10, or 12 hours—all resulted in similarly lean mice.

Benefits Continued Even When Diet Was Interrupted 

The researchers gave some of the time-restricted eating mice a break from the restriction on weekends, allowing them unrestricted food access 24-hours a day for those 2 days.  Still, these mice experienced very similar benefits to those whose eating was restricted 7 days per week.  They had less fat mass and gained less weight than the mice whose eating periods were never restricted.

This suggests that the benefits of time-restricted eating will persist regardless of occasional interruptions.  “The fact that it worked no matter what the diet, and the fact that it worked over the weekend and weekdays, was a very nice surprise,” says the study’s first author Amandine Chaix.


Obese Mice Dropped 5% of Body Weight in Days

Especially exciting was the finding about obese mice.  When researchers restricted their food access to a 9-hour window, these mice dropped 5% of their body weight within a few days—despite eating the same number of calories as before!  More importantly, time-restricted eating kept them from gaining further weight, whereas mice on an unrestricted high-fat diet throughout the study gained another 25% of their body weight by the end of the 38 weeks.
These results were published recently in the journal Cell Metabolism.  The authors say that “time restriction better synchronizes the function of hundreds of genes and gene products in our body with the predictable time of eating.”