While several intermittent fasting plans limit eating to six or eight hours a day, a food consumption window as long as 10 hours may still help your overall well-being, according to new research.
The study, which involved more than 37,000 participants, found that hunger, mood, and sleep can all improve with a daily schedule of fasting for 14 hours. Under this type of plan, for example, a person might take a first bite at 9 a.m., and then finish eating for the day by 7 p.m.
Presented this week at the European Nutrition Conference, the findings also highlighted that consistency counts: Those who maintained the same time frame for fasting had greater benefits than those who varied their eating window day to day.
“Our participants fasted for 14 hours against the noisy backdrop of our day-to-day lives and found there was a big improvement in how they felt,” says Sarah Berry, MD, an author of the study, a researcher at King’s College in London and chief scientist with the ZOE Health Study, a research project that uses data reported via a mobile app. “A 10-hour eating window is pragmatic and achievable for most people.”
“I was surprised that even reducing your eating window by, on average, two hours, there is still a really big improvement on how people felt,” she adds.
Intermittent Fasting Led to Improvements in Health Measures All Around
For the analysis, Dr. Berry and colleagues evaluated self-reported information from 37,545 users of the ZOE health app, who were asked to follow their regular eating pattern for one week and then switched to a 10-hour eating window for at least two weeks. More than 96 percent opted in for additional weeks of the intermittent fasting plan, and over 70 percent were classified as highly engaged, meaning they regularly logged in and completed questionnaires.
The scientists observed that those who followed the 14-hour intermittent fasting plan over a longer period reported higher energy, better mood, improved sleep, and lower hunger. They also observed less benefit for people who were inconsistent and varied their eating window day to day.
Overall, just over half of highly engaged users reported a small reduction in weight over 2 to 16 weeks — an average of almost two and a half pounds.
Of the highly engaged, nearly 8 out of 10 were female, with a mean age of 60 and a body mass index of 25.6, which is within the overweight range, according to the Centers for Disease Control and Prevention (CDC). ZOE has noted previously that its respondents are overwhelmingly female.
The investigators wrote that the older average age suggests that an older population is more likely to stick to a time-restricted eating plan.
“We believe this is more feasible in their life compared to younger people,” says Kate Bermingham, PhD, another author of the study and a postdoctoral researcher at King’s College and at ZOE.
Real-Life Results Support Time-Limited Eating Plans
For Lilian de Jonge, PhD, a professor in the department of nutrition and food studies at George Mason University in Fairfax, Virginia, this new analysis builds on previous research demonstrating the potential positives of intermittent fasting.
“Almost all research on time restrictive eating has been performed as a clinical trial with relatively small groups of participants in a controlled environment,” she says. “This study is done in a very large group of free-living people, which provides information on compliance and practicality.”
These types of intermittent fasting plans can be very effective for those who are trying to lose weight but find it difficult to count calories, according to Alaina Vidmar, MD, a pediatric endocrinologist, obesity medicine specialist, and the medical director of the Healthy Weight Clinic at Children’s Hospital Los Angeles.
“Counting calories every day is really hard, and it can be really cumbersome,” says Dr. Vidmar. ”This study highlights that time-restricted eating might be just a more simple approach for some groups of people.”
She further suggests that intermittent fasting by its nature may reduce calorie-intake by limiting the window during which a person eats.
“This type of eating plan may also help the body’s metabolic system utilize its calories more efficiently, so things like glucose, insulin, cortisol, and other hormones may be at their most optimal alignment.”