When you workout in the morning without eating breakfast beforehand, your body doesn’t have calories available to use as fuel. Since the body needs something to fuel the motion, it will start burning carbohydrate stores and fat instead.
Despite this concept, the concern with skipping breakfast is that you will end up binge eating later to replace the lost calories, undoing your hard work. A new study published in The Journal of Nutrition sought out to explore this relationship further.
Researchers at the University of Bath asked participants to report to an exercise lab on three different mornings. The first morning, participants consumed a bowl of oatmeal containing 430 calories and then rested. The second morning, they ate the same oatmeal and then rode a bike at a moderate pace for 60 minutes. The third and final morning, they skipped breakfast but rode the bike.
In order to track the participants’ consumption throughout the rest of the day, researchers sent them each home with a basket of food. Participants were asked to eat only from the basket and bring back anything they didn’t eat. The scientists also tracked the participants’ energy expenditure over the 24 hours.
When participants ate breakfast and then rested, they consumed approximately 490 more calories than they burned that day. This is not shocking, and would trend toward weight gain over time.
The second morning, when they ate breakfast and then exercised, they just about broke even. The number of calories participants burned that day was almost exactly the number of calories they consumed.
When the participants skipped breakfast before exercise, they had a deficit of around 400 calories at the end of the day. This means they burned 400 more calories than they consumed, which would lead to weight loss if repeated.
Interestingly enough, the participants ate significantly more at lunch that third morning than they had before, but they still rounded out the day with a calorie deficit. This suggests that working out on an empty stomach in the morning may affect how much we eat in total all day long-- alleviating the fear of undoing your hard work at lunchtime.
Although this is only one short-term study, the findings are definitely intriguing. If you’re looking to lose weight, consider skipping breakfast before hitting the gym.
Read more in The New York Times.