Does exercising on an empty stomach burn more fat? What fasted workouts really do to the body

Solen Le Net

By Solen Le Net


Published: 09/02/2026

- 15:50

Fasted exercise encourages the body to use fat as fuel, but it doesn't necessarily lead to greater weight loss

The idea of hitting the gym before breakfast has become popular among fitness enthusiasts hoping to burn more fat. But does it actually work?

Exercising on an empty stomach does boost fat-burning during your workout. Dr Asiya Maula, general health practitioner at The Health Suite, explained why this happens.




"Exercising in a fasted state can increase fat oxidation during the session because insulin is lower and the body is more likely to use fat as fuel," she told GB News.

"But that doesn't automatically mean you'll lose more body fat overall - your total calorie balance across the day still matters most."

SENIOR MAN EXERCISING

Fasted workouts aren't suitable for everyone

|

GETTY

However, fasted workouts aren't suitable for everyone and can sometimes do more harm than good.

Some people experience unpleasant side effects like feeling dizzy, shaky, sick, or simply lacking energy, which can really hamper performance.

Dr Maula warned that certain groups face particular risks.

"If you're prone to low blood sugar, have diabetes, a history of fainting, or are on glucose-lowering medication, fasted exercise can increase the risk of hypoglycaemia," she said.

Those with thyroid problems should also be cautious, as Dr Maula noted that stability is the main concern, particularly for people with hyperthyroidism whose symptoms aren't well managed, as intense exercise could be dangerous.

Seeking personalised medical guidance is recommended for people in this group.

Research shows that while you might torch more fat during a fasted session, this doesn't reliably lead to greater fat loss over weeks and months.

Studies have found that when people train with similar intensity and eat roughly the same calories, body fat reductions end up being pretty much identical whether they exercise before or after eating.

Dr Maula explained: "The body compensates - you might burn a higher proportion of fat in the session, but you may subconsciously move less later, feel hungrier, or eat more, so the overall fat-loss result evens out."

That said, fasted training can still be a good option for some people, particularly when it comes to sticking with a routine.

If completing a morning walk or gentle jog before breakfast is the easiest way to make exercise happen, it can work really well.

MEASURING TAPE

'Exercising in a fasted state can increase fat oxidation'

|

GETTY

But for tougher workouts like interval training, longer runs, or heavy lifting, most people perform better with some food in their system.

Dr Maula pointed out that having fuel beforehand can boost training quality and help you stay consistent, and that's often what really drives fat loss in the long run.