Dr Colin Waine, of the National Obesity Forum, said obese children were up to 20% more likely to develop cancer as adults than those of a healthy weight.

He added that lots of kids are now getting diseases because of their weight that normally only adults get.

Dr Waine wants the government to do much more to make kids more healthy because he says things will get worse.

But the government says it is doing lots to try and get the better of obesity, including encouraging children to take physical exercise.

They are also waiting for a very important report later in the summer about the link between advertising and how much junk food kids eat.