The most important meal of the day may not be the most important meal of the day after all. That’s according to a new small study that explores the effect of eating breakfast on your appetite.
Researchers from the University of Scranton in Pennsylvania looked into how eating or not eating first thing in the morning influenced how much people ate during the rest of the day. They found out that those who skipped their first meal of the day and went straight into their workouts ate far less on average than those who broke their fast.
The researchers invited 12 white men aged between 18 and 23 to come to their laboratory every morning for two weeks. They were randomly assigned into separate groups. The breakfast group were given a bowl of oatmeal and orange juice, while the no-breakfast group received nothing. After two hours, both groups of men had to run on a treadmill for 60 minutes.
The roles were reversed on the second week. The second group received the same meal of oatmeal and orange juice when they arrived at the lab, while the first group were not given anything.
Throughout the experiment, the participants also received food they can eat throughout the rest of the day and were allowed to eat as much as or as little as they wanted. At the end of the day, they had to return the leftovers to the lab, which the researchers measured to see exactly how many calories each participant consumed.
The results show that the men who skipped breakfast before exercise ate a great deal less than those who ate breakfast before going on the treadmill. This goes straight in the face of common knowledge that eating breakfast helps you feel more satisfied throughout the rest of the day, thus making you eat less.
Specifically, those who did not eat breakfast before working out consumed an average of 3,600 calories every day, which is far less than the 4,500 calories that the breakfast eaters consumed on average.
The no-breakfast group were also able to burn more fat while exercising in a fasted state than the men in the fed group, supporting an increasing number of studies suggest that working out before breakfast is more effective for fat loss.
The researchers say the randomized, controlled study is one of the very few that looks into the relationship between eating or not eating breakfast and weight loss. Although a number of observational studies have noted that people who do not eat breakfast regularly actually weigh more than people who do, the researchers say there are no randomized, controlled trials that support this observation.
“People have been looking for a while at how exercise affects appetite,” Jessica Buchanan, lead researcher and assistant professor and exercise science at the University of Scranton, tells LiveScience. “What really hasn’t been manipulated is whether consuming breakfast affects this at all.”
Buchanan and her team believe that their findings could help people design an effective weight loss or weight maintenance program that takes into account the amount of calories consumed versus the amount of calories expended.
“Energy balance, (which is) the relationship between energy consumed and energy expended, is a simple equation on paper but is a complicated concept in practice that ultimately determines whether an individual’s weight increases, decreases, or stays the same,” the researchers explain.
The study adds to a growing body of research that indicate that eating breakfast may not be all that it’s cut out to be. Various studies show that skipping breakfast does not cause people to pig out the rest of the day but, in fact, suppresses the appetite even more. As this is a relatively new observation, scientists have yet to find out the mental mechanism that explains why this happens.
Granted, the researchers say they had a small, homogenous sample size, thus the results of the study cannot be applied across all groups of people. They also emphasize that they did not look into the results of the experiment beyond one day.
Further research is recommended to investigate the effects of skipping breakfast across larger populations and a wider span of time.
The study is published in the Journal of Nutrition and Metabolisms.