NASA's global gravity survey satellite launched last month has revealed why Americans and the British are classified as becoming more obese than other nations, while continents like Africa have more skinny people.
"They have mapped in fine detail the gravity map of the Earth," said professor Brian Cox. "It shows that the highest gravity on Earth is concentrated over America and Britain, extending somewhat into the Netherlands. Africa has the lowest gravity."
The gravity map from NASA portrays the earth as looking like a misshapen potato, and the differences in gravity across the planet have brought forth surprise from scientists who had not realised that there would be such a difference. With increased gravity comes higher weight in direct proportion, so people living in stronger gravitational fields will weigh more.
"The highest gravity on Earth," said Cox, "is centred over the Southern states of America. The lightest is over mid-Africa."
Not everybody agrees with the finding, with Professor Gillian McKeith suggesting that the higher gravity is caused by the mass of all the fat people in the areas that show up as having higher gravity. But nobody believes a word she says, so this theory has been discounted.
The news that weight can be changed by simply moving from one continent to another has unleashed a raft of new diet books. The top seller is called Emigrate to Lose Weight and encourages people to move to Kenya.
Renowned tubby, Jamie Oliver, has greeted the news with joy.
"I'm weally pleased I can shed a few pounds by moving to Afwica," he lisped. "I've alweady booked my flight."