Exercise professionals might find it interesting that working out before you eat really does make food taste better - at least if a study based on animal behaviour is to be believed.

It's also suggested that the more effort a gym member puts into exercising, the better the food tastes - and that exercise could even enhance people's appreciation for foods you might not usually fancy, such as low-fat and/or low-calorie snacks.

The research could support the view that offering members the option of purchasing healthy snacks at gyms could be a good revenue source.

Lead researcher Alexander Johnson from John Hopkins University in the US said: "What we've shown is that, if you have to expend more effort to get a certain food, not only will you value that food more, but it might even taste better to you."

Mice were trained to respond to two levers - one which they had to press once to get food and the other 15 times.

"When given free access to the levers, the rodents "clearly preferred the food they worked harder for".