As the summer vacation starts they've been trying out loads of different sports, and learning to eat more healthily.
Brother and sister Jamal, 11, and Janeisha, 8, have been spending time at the camp, and have both lost around a stone (6.35 kg) in weight!
They say they feel loads better with the weight off.
Jamal said: "Having the weight on, it was harder to do things.
"I couldn't really run very fast, or jump very high either."
As the weeks went by and he saw the weight drop off, Jamal said: "I felt proud of myself and a whole lot better."
His sister Janeisha said: "When I had the weight on me it was horrible, because I couldn't jump, and I couldn't bend down."
Now Janeisha says she can jump higher and bend down properly.
the first time some of them had their fees paid by the local hospital.
Camp organisers say most of them are expected to keep the weight off, because they're taught how to stay healthy when they go home.