The study has found that people who finished eating all their meals by early afternoon had smaller fluctuations in hunger and burned slightly more fat than people who ate throughout the day.
According to Courtney Peterson, the study author and an assistant professor of nutrition sciences at the University of Alabama at Birmingham in the US, the results show the timing of calories likely does matter. Although more research is needed, she said.
Peterson said the more you can eat your food earlier in the day, even if you’re not changing the timing of your meals, the better.
She said that though not everyone can always change their diet, almost everyone has some sort of control over when they eat or how much food they consume at each meal.
The timing of meals may matter because the body has an internal clock — the circadian rhythm, which follows a 24-hour cycle — and does certain things better at different times of the day, Peterson explained.
“We know your best blood sugar control is in the morning,” she said. “We also know that when you eat food, the energy it takes to digest it is a little higher in the morning.”
Research in mice has already found rodents who graze throughout the day gain more weight than those who eat all their food within a window early in the “rodent day.” Mice that munch when they should normally be sleeping may also disrupt their learning and memory.
For the study, 11 people tried two eating schedules for four days. In one, they ate all their food between 8:00 AM and 2:00 PM. In the other, they engaged in a more typical meal schedule, starting to eat at 8:00 AM and finishing at 8:00 PM. They ate exactly the same amount of calories on both eating schedules.
The changes didn’t affect how many calories people were burning, the researchers found. But when the participants ate all their food early in the day, they burned about 6% more fat and their hunger levels were more even throughout the day, even though they were essentially fasting for 18 hours between dinner and breakfast. Perhaps that’s because when your body realizes you’ve had all your calories for the day, there’s no need to get hungry, Peterson theorized.
The findings might be promising for weight loss, she said.
If you’d like to try a similar eating plan, she noted most people find squeezing all their meals into a six-hour window to be too difficult. Eight hours — from 8:00 AM to 4:00 PM, for example — is more doable, she said.
Another strategy may be to keep the same meal times, but make breakfast and lunch your biggest meals, Peterson said. In other words, follow the old adage: Eat breakfast like a king, lunch like a prince and dinner like a pauper. Traditional societies, like the Mediterranean culture, often do just that and consume their biggest meal in the middle of the day.