Asset 19 angle-down-bold angle-left-bold angle-right-bold angle-up-bold Asset 10 certifications Asset 14 close-bold close Asset 8 Asset 12 menu Asset 18 Asset 17 Asset 6 Asset 16 Asset 9 Asset 15 Asset 11 Asset 13

Get answers to all your questions!

Things like:

How long is the program?
Is the program and exam online?
What makes ACE's program different?

Call (888) 825-3636 or Chat chat icon now!

March 2013

Study: A Calorie is Just a Calorie, But When You Eat it is Important, Too


In life, they say, timing is everything. The same may be true for losing weight as well. New research suggests that, while calories are important, whenyou consume them may have a significant effect on how much weight you lose.

Most weight-loss plans center around a balance between caloric intake and energy expenditure. However, new research sheds light on a new factor that is necessary to shed pounds: timing. Researchers from Brigham and Women's Hospital (BWH), in collaboration with the University of Murcia and Tufts University, have found that it's not simply what you eat, but also when you eat, that may help with weight-loss regulation.

“This is the first large-scale prospective study to demonstrate that the timing of meals predicts weight-loss effectiveness,” says Frank Scheer, Ph.D., M.Sc., director of the Medical Chronobiology Program and associate neuroscientist at BWH, assistant professor of medicine at Harvard Medical School and senior author on this study. “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 a weight-loss program.”

To evaluate the role of food timing in weight-loss efforts, researchers recruited 420 overweight participants to follow a 20-week weight-loss treatment program in Spain. The participants were divided into two groups: early-eaters and late-eaters, according to the self-selected timing of the main meal, which in this Mediterranean population was lunch. During this meal, 40 percent of the total daily calories are consumed. Early-eaters ate lunch anytime before 3 p.m. and late-eaters, after 3 p.m. They found that late-eaters lost significantly less weight than early-eaters and displayed a much slower rate of weight-loss. Late-eaters also had a lower estimated insulin sensitivity, which is a risk factor for diabetes.

Researchers found that timing of the other (smaller) meals did not play a role in the success of weight loss. However, the late-eaters—who lost less weight—also consumed fewer calories during breakfast and were more likely to skip breakfast altogether. 

In the study, which was published in the January 29, 2013, issue of International Journal of Obesity, researchers also examined other factors that often play a role in weight loss, such as total calorie intake and expenditure, levels of the appetite hormones leptin and ghrelin, and sleep duration. Among these factors, they found no differences between the late-eater and early-eater groups, suggesting that the timing of the meal was an important and independent factor in weight-loss success.

“This study emphasizes that the timing of food intake itself may play a significant role in weight regulation,” explains Marta Garaulet, Ph.D., professor of physiology at the University of Murcia Spain, and lead author of the study. She suggests that weight-loss efforts should focus on not only caloric intake, macronutrient distribution and exercise, but the timing of meals as well.

In other words, it appears the old adage to "breakfast like a king, lunch like a prince and supper like a pauper" may be good advice after all.

Garaulet, M. et al. (2013). Timing of food intake predicts weight loss effectiveness. International Journal of Obesity, DOI: 10.1038/ijo.2012.229.

Search This Issue
Keeping You Posted


Part of our mission at ACE is to connect qualified fitness professionals with people who need them most, which we do through our Find an ACE Trainer tool at Make sure you’re putting your best foot forward by updating your My ACE profile today.
Read More »


Join ACE Exercise Physiologist Pete McCall for ACE's newest free webinar, Understanding Myofascial Anatomy, on March 20. Learn how fascia and connective tissues work synergistically to control movement, and methods of organizing exercises tailored to the way your clients move.
Read More »


Named the “World’s Greatest Athlete” at the 2008 Olympics, Bryan Clay went from being a drug-abusing kid to a gold medalist in the decathlon. Hear how he’s used his struggles to help others at ACE West on May 16-18 in San Diego, Calif.
Read More »

Ace Certified News

ACE's Certified News is produced 12 times per year by the American Council on Exercise. No material may be reprinted without permission.

Publisher: Scott Goudeseune
Technical Editor: Cedric X. Bryant, Ph.D.
Editor In Chief: Christine J. Ekeroth
Art Director: Karen F. McGuire