What to eat before a workout and when is best to exercise, is often highly contested. Now a new study has suggested that eating nothing beforehand might be the best way forward.
A study published in the American Journal of Physiology by
researchers at the University of Bath found you might be likely to burn
more fat if you have not eaten first.
Researchers studied a group of overweight males who walked for 60
minutes at 60 per cent maximum oxygen consumption in one scenario on an
empty stomach and in another two hours after eating a high-calorie,
carb-based breakfast.
Their blood samples were taken after eating or fasting and then after
exercising. Gene expression in fat (adipose) tissue differed
significantly in each scenario and the expression of two genes increased
when the men fasted and exercised and decreased when exercising after
eating. This likely signals that stored fat was used to fuel metabolism
during exercise rather than the carbohydrates from the meal.
After eating, the fat tissue is “busy responding to the meal and a bout
of exercise at this time will not stimulate the same [beneficial]
changes in adipose tissue. This means that exercise in a fasted state
might provoke more favourable changes in adipose tissue and this could
be beneficial for health in the long term,” author of the study Dylan
Thompson wrote.
Adipose tissue plays an important role during exercise and during
moderate exercise provides much of the energy for working skeletal
muscle
Mr Thompson said that as adipose tissue is impacted by weight loss
and weight gain (the genes increase in weight loss and decrease in
weight gain) their research proposes “feeding before exercise blunts
some of the health-related changes induced by exercise training”.
However, the study does have limitations in the fact only ten men
were measured and it only measured the effects of skipping breakfast on a
morning workout, not other mealtimes. The study also does not mean that
skipping a meal before exercising will result in accelerated weight
loss.
Ruben Tabaras, a personal trainer and strength and conditioning coach, recently told The Independent he personally does not eat before a workout as it makes him feel unwell.
“If the stomach is digesting food then it is using bloody to do so
and that blood could better be used in the muscles, hence why people
feel sick when working out,” he suggested.
However, many athletes and other personal trainers ensure they eat
something carb and protein heavy in order to have the correct amount of
fuel in their body to power them through a tough workout.