Children will be encouraged to give up their Easter eggs in return for a chance to learn about the dangers of being fat.
The Science Museum is holding an Easter egg amnesty on April 13 when children will be offered free admission to its science of sport exhibition.
If they hand over an Easter egg the normal pound;6.95 entry fee will be waived.
In return for their egg, children will get the chance to take part in a range of hands-on activities designed to teach them about the importance of a balanced diet and exercise.
Children who attend can run on a treadmill wearing a specially designed "fat pack", check the accuracy of their tennis shots and measure their own fat levels using a body mass indicator.
Other exhibits include a breathing device used by Jonny Wilkinson, England's Rugby Union World Cup winner and leak-free swimming goggles.
The exhibition is supported by the British Diabetic Association. Last month three leading medical colleges warned of a "terrifying" rise in type 2 diabetes among children as a result of obesity.
Tessa Sanderson, the 1984 Olympic javelin gold medallist who is now chair of Sport England, said: "Food is the fuel that powers physical activity so this is a great way of highlighting the role it plays - and also the dangers of not getting the balance right."
Children who feel they need to refuel after a couple of hours burning calories should not despair. They will have the option of retrieving their Easter egg when they leave the exhibition.