I’m kicking this week off with a piece of provocative news: UK researchers are reporting that the best way to win the battle of the bulge and lose fat is to exercise on an empty stomach.
Mind you, the study (which appears in the online in the British Journal of Nutrition) is small. But, researchers say that by omitting breakfast before exercise, you might be more inclined to eat a more optimal balance of food throughout the day. In fact, when twelve physically active men participated in one of four scenarios — rest without breakfast, exercise without breakfast, breakfast followed by rest, or breakfast followed by exercise –that is actually what they found.
A bit of detail is in order here:
Men who exercised had a moderately intense run on a treadmill, during which time they expended approximately 700 calories. (Note that for the men assigned rest, an equivalent time was spent resting as on the treadmill). After exercising or resting, all the groups had a protein drink comprising approximately 444 calories. Ninety minutes later, they had lunch (pasta) and advised to eat as much as they wanted until they felt comfortably full. Then, the researchers measured energy and fat levels in the blood.
Interestingly, exercising in the morning (around 10 am) appeared to help balance out the day in terms of food and no attempts appeared to be made to compensate for the earlier activity in terms of caloric intake; appetite was also unaffected. But, here’s the critical piece: exercising in a fasted state appeared to increase the amount of fat burned by as much as 20%. And, while eating breakfast appeared to improve overall appetite throughout the day (helping to insure that it remained more balanced and did not lead to additional consumption), it tended to cancel out any appetite-suppressive benefits offered by exercise.
The bottom line is that by fasting before exercising, you may be able to accelerate fat loss. The question remains as to whether or not the same results can found in women and among larger numbers of individuals. And if these fat loss remains over time.
I’d love to hear from some RDs and fitness folks out there. What do you think?