Fattypuffs And Thinifers
by André Maurois
genre: young adult, political satire
Summary from Goodreads
‘If you go on eating like that you’ll turn into a real Fattypuff,’ thin Mr Double said to his plump son Edmund. He was right, for when Edmund and Terry found the secret staircase in the wood which led to the underground countries, Edmund had to go with the Fattypuffs to their city, where people were huge and happy and ate all day long, while Terry went off with the Thinifers, who were as spiky and prickly as their city. And it took a war as well as a lot of argument before the boys could teach them to agree about anything.