Collapsing into giggles could burn as many calories as a brisk walk, according to scientists.
Even a sneaky snigger could give your muscles a workout, burning around ten calories an hour, a study found.
Dr Helen Pilcher, a comedian who has a PhD in biology, reviewed research on the dietary effects of laughter.
Her results showed that the most intense form of laughing - defined as flat out, uncontrollable, roll on the floor howling - was found to burn 120 calories an hour, similar to the amount burnt by walking at a moderate pace.
Hearty belly laughs can burn up to 100 calories per hour, while irrepressible chuckling can burn up to 20 calories per hour.
And a good laugh can help you to tone your stomach - meaning you could be honing your abs while sitting on the sofa watching TV. Scientists have discovered that one group of muscles, the internal obliques, which are important for creating a 'six pack', are activated more by cackling than by stomach crunches.
Having a good guffaw also boosts blood flow, contributing to a cardiovascular workout that uses energy and so burns calories.
Dr Pilcher, who was commissioned by channel Dave to do the study, argued that laughing at comedy shows can contribute towards weight loss "provided you don't eat any pies while you watch them".
She added: "This report raises the joyous possibility that watching comedy shows can help you to shape your six pack by targeting internal oblique muscles more effectively than sit-ups.
"I definitely felt more toned after watching hours of TV comedies."
Timandra Harkness, co-founder of writing group The Comedy Project, said: "Laughter is no replacement for going to the gym. But let's face it, it's a much more inviting prospect on a wet, chilly winter evening."
- Daily Mail