Shedding Fat Before Breakfast

Weight loss maximized while exercising on empty stomach

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) If maximizing weight loss is the goal, it may be better to save the oatmeal until after the morning jog, instead of before.

A recently published study found that people who exercised in the morning on an empty stomach burned up to 20 percent more body fat than those who ate breakfast before exercise.

"Work out first, then eat breakfast."

Researchers, led by Javier Gonzalez, a PhD student in the Brain, Performance and Nutrition Research Center at Northumbria University in the UK, investigated how breakfast and exercise affected energy and metabolism in physically active men.

Researchers examined 12 young men who were an average of 23 years old and regularly exercised. 

The men fasted overnight and participated in four different exercise tests. The tests included resting without breakfast, exercising without breakfast, eating breakfast followed by resting and, finally, eating breakfast followed by exercise.

The men logged what they consumed in the 24 hours leading up to their tests. Caffeine, alcohol and vigorous physical activity were not allowed going into testing.

After the tests, the participants were given a chocolate milk test drink and lunch to measure the fat and energy burned during the morning.

Researchers found that working out while in a fasted state led to almost 20 percent more fat burned compared to eating breakfast before exercising.

Those who exercised in the morning did not consume extra calories during the day to make up for the work out. These participants also did not feel hungrier throughout the course of the day.

Hunger was suppressed by about 17 percent while in a fasted state. Meanwhile, being fed suppressed hunger by 9 percent.

"The present study found that, compared with rest, exercise suppressed hunger and overall appetite to a greater extent when fasted, compared with the fed state," researchers wrote in their report.

"Nevertheless, it should be noted that appetite was higher in the fasting state prior to exercise."

The participants were more fit overall than the average population, researchers said, so the results may be more trivial compared to a less active population.

"This could be due to the fact that subjects in the present study are regular exercisers and therefore displaying better basal glucose tolerance," researchers wrote.

The researchers noted they did not include women in their study or focus on how being overweight and obese comes into play. Future research should look into the other populations. The study was very small, so larger studies with a greater patient population must be done before these findings could be considered representative of the general population.

The study was published January 29 in the British Journal of Nutrition. The study received no outside funding, and no conflicts of interest were declared.

Reviewed by: 
Review Date: 
February 24, 2013
Last Updated:
February 27, 2013