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Most weight loss advice focuses on calories consumed and calories burned, but new research has highlighted the importance of timing when it comes to shedding pounds.
In collaboration with Spain's University of Murcia and Tufts University, BWH's Frank Scheer, PhD, MSc, has found that it's not simply what you eat, but also when you eat, that can help you lose weight. The study was published in the International Journal of Obesity late last month.
"This is the first large-scale prospective study to demonstrate that the timing of meals predicts weight loss effectiveness," said senior study author Scheer, associate neuroscientist and director of BWH's Medical Chronobiology Program. "Our results indicate that late eaters displayed a slower weight loss rate and lost significantly less weight than early eaters, suggesting that the timing of large meals could be an important factor in weight loss."
To evaluate the role of food timing in weight loss effectiveness, researchers studied 420 overweight participants who followed a 20-week weight loss treatment program in Spain. The participants were divided into two groups: early eaters and late eaters, according to the timing of their main meal, which was lunch. During this meal, 40 percent of the total daily calories are consumed. The early group ate lunch anytime before 3 p.m. and late eaters, after 3 p.m. Researchers found that late eaters lost significantly less weight than early eaters, and displayed a much slower rate of weight loss.
The timing of other smaller meals did not seem to play a role, but late eaters consumed fewer calories during breakfast and were more likely to skip breakfast altogether. Late eaters also had a lower estimated insulin sensitivity, a risk factor for diabetes.
When it came to total caloric intake and expenditure, appetite, hormones and sleep, researchers found no differences between the two groups, suggesting that the timing of the meal was an important and independent factor in weight loss success.
"This study emphasizes that novel therapeutic strategies should incorporate not only the caloric intake and macronutrient distribution, but also the timing of food," said Marta Garaulet, PhD, lead study author and professor at the University of Murcia.