Intermittent fasters have long known that spacing out meals into intervals makes them feel better and helps keep their weight in check. And now, new mainstream medical research is further confirming that fact, with findings suggesting that 10 hour feeding windows provide the optimal routine for health-seekers.
The research also encourages beginning the feeding window early in the morning with a balanced breakfast. Participants who ate meals four hours later in the day were “more hungry, burned calories at a slower rate, and had body changes which promoted fat growth,” according to the study at Brigham and Women’s Hospital, published this week in the peer-reviewed journal Cell Metabolism.
“In this study, we asked, ‘Does the time that we eat matter when everything else is kept consistent?’” said first author Nina Vujovic, a researcher who specializes in circadian disorders. “And we found that eating four hours later [and skipping breakfast] makes a significant difference for our hunger levels, the way we burn calories after we eat, and the way we store fat.”
The study took overweight patients and assigned them 10-hour feeding windows (intermittent fasting); but assigned different windows to different groups. For example, a participant in the early group might eat at about 9 a.m., 1 p.m. and 5 p.m.; the other group at 1 p.m., 5 p.m. and 9 p.m.
There’s no such thing as a perfect intermittent fasting calculator, but eating early does have its medical benefits
Participants tracked their own hunger levels, and researchers took blood samples and body fat tissue to help determine hormone levels throughout the day. According to researchers, late eating more than doubled the likelihood of being hungry. Late eating also caused lower levels of the hormone leptin, which is present when we feel full, researchers said.
“We wanted to test the mechanisms that may explain why late eating increases obesity risk,” senior author Frank Scheer, director of the medical chronobiology program in Brigham’s division of sleep and circadian disorders, said in a statement. “This study shows the impact of late versus early eating. Here, we isolated these effects by controlling for confounding variables like caloric intake, physical activity, sleep, and light exposure, but in real life, many of these factors may themselves be influenced by meal timing. In larger scale studies, where tight control of all these factors is not feasible, we must at least consider how other behavioral and environmental variables alter these biological pathways underlying obesity risk.”
So what does this study mean for you? It means you should always be tinkering with your health until you dial in an eating schedule that works best for your body. Eating a healthy breakfast and then finishing the day with an early dinner may be the exact methodology that changes your body composition and helps you feel more energized and focused throughout the day.
Some extremely healthy people, however, swear by skipping breakfast and keeping their eating window from lunch to a dinner around 6 or 7 pm. Neither option is explicitly better than the other; what’s important is that you understand the power of intermittent fasting, then choose whole, nutritious foods, and finally tinker with the process until you feel your best.