Early risers who exercise before breakfast can burn up to 20% more body fat than others who exercised after having something to eat, says a study.
Researchers sought to find out if the known benefits of exercising after an overnight fast were undermined by an increased appetite and eating more food later in the day.
A team from University of Northumbria at Newcastle asked 12 active men to perform a bout of treadmill exercise at 10 am, either after having breakfast or in a fasted state; having not eaten since the previous evening.
After their exercise, all participants were given a chocolate milkshake recovery drink.
Later in the day, participants were provided with a pasta lunch which they were asked to eat until they felt "comfortably full".
Their lunchtime consumption of energy and fat was assessed and calculated, taking into account the amount of energy and fat burned during the morning period.
The researchers, led by Emma Stevenson and Javier Gonzalez, found the ones who had exercised in the morning did not consume additional calories or experience increased appetite during the day to compensate for their earlier activity.
It was also found that those who exercised in a fasted state managed to burn nearly 20% more fat than those who had taken breakfast before their workout.
It showed that performing exercise on an empty stomach provides the most desirable outcome for fat loss.