He was deliberately being provocative with his comments, but i understand where he is coming from after he put up a video explaining in more detail.
A child that is falling behind academically at school will be given help and support to catch up. If a child is very overweight and unhealthy, no support is given to then or their family to help change that. That child then grows up with a higher chance of getting certain health issues due to their weight.
I think shows like Gladiators will be inspiring a lot of kids to take up sports or become more active.
There needs to be more done though. Funding local sports clubs and school facilities. Better support and education for parents. But as with all things these days, there is not enough money for this.