Imagine your typical primary school classroom. It's probably filled with about 30 kids. Now, can you imagine how many would be overweight or obese?
Well, thanks to the government's National Child Measurement Programme (NCMP), we know that five or six of the kids in your imaginary classroom will probably be obese and another four or five will be overweight.
Now let's multiply that out across England, maybe even across the UK, and we've clearly got a big problem on our hands.
The NCMP measured 499,867 Year Six children in England. The results show 73,069 kids were overweight and 93,649 were obese. These youngsters are not even teenagers and yet more than a third of them were overweight or obese.
I'm certainly not trying to scaremonger, but the fact is childhood obesity has some really long term implications for the health of the nation.
Nobody can afford to ignore the problem. It's been shown obese children are more likely to become obese adults. And obesity in adults is associated with an increased risk of type 2 diabetes and heart and circulatory disease.
But what can actually be done about childhood obesity?
Well, the UK's government and food industry certainly have a role to play.
Firstly, children need healthy environments to help them lead healthier lives. That means a chance to get active at home and in school; kids who are physically active have a much better chance of becoming healthy adults.
The problem is up to 30% of boys and 40% of girls are not hitting recommended minimum levels of physical activity - that's at least an hour each day.
Neighbourhoods, parks and green spaces need to be well designed and maintained to encourage healthy lifestyles. And schools must maximise the opportunities for children to get active during the school day and to take part in extracurricular activities.
The food industry must also pledge to cut the amount of salt, saturated fat and sugar in its products, while the government must get tough on regulations around how junk food is marketed to our kids. That includes the way food manufacturers use the internet and social media. Unhealthy products aren't allowed to be advertised to children on TV, so companies shouldn't be able to promote them to kids online either.
Organisations like the BHF have a role to play too. That's why we're on the verge of launching our new Food4Thought campaign which is aimed at helping tackle the problem of childhood obesity. Our new survey results, due out next week, lift the lid on what our children are really eating and it doesn't make great reading. I won't give too much away, but fruit and veg are clearly not the order of the day!
So, yes, we've got a problem with childhood obesity. But then that won't come as surprise to many people. What we need to do now is all pull together to get a grip on the problem; that means work for you, me, politicians, food industry bosses, parents, teachers and kids.
There is no one magic bullet that will do the job but healthier lifestyles; sensible, robust and coordinated policy; education programmes; and commitment from food companies will all make the difference.
We have to do something because otherwise this very big problem is not going to go away.