"Sturdy" grandson.

Sounds a bit like taking the easy option using iPad etc. I encountered a similar problem and grandson is now an obese adult with no interest in physical activity at all. You can only try to include him in activities and encourage but it's not easy.

13 is a time of growth spurts and kids go out, then up, then out, then up A year ago I thought one of my grandaughters was getting a bit chubby, also not interested in sport however now at 13 she is a beanpole gone up to 5 ft 8 and really has a lovely figure 13 is also an age when kids can be likely to get anorexic ( boys and girls ) if told they re getting chubby so from my point of view I d not worry too much and not say anything to him at all

Introduce him to Pokemon Go at least he'll be out of the house and moving

Is your son an inactive type of person?

Join him up to the Scouts. He is missing so much.

And what Tanith said*. Seriously.

Would he like the idea of a FitBit?

I'd echo what Bluebelle says. When DS2 was in his teens he was chubby, then skinny, then chubby and then skinny etc. He could eat for England but was very sporty. He is now a tall, slim almost 43 year old.

Is he interested in girls?
They can sometimes change the situation around.

I would personally, if I were the parent try and do something.
But they may already be doing so.
Another thing to consider is if there is an underlying problem of some sort, either physical or emotional. But there may not be.

You cant join' a child to anything if they are not interested some kids are sporty some aren't, some are 'made' to be sporty and it puts them off for life..... would you be worked up if he was a child who sat reading or doing homework in his room all the time. You can encourage things by taking them to activity places as a family or join the gym with them or going for a family cycle ride but you cant just 'join'' them to scouts or gym or football if hes not interested Scouts is great and my two that live near me do go but its only one evening a week and occasional camps so wouldnt necessarily make much difference
He will go up and down and maybe by next year hes be a string bean without any input

You can expose, and encourage. Maybe Dad should become a helper. But it's all likely to be genetic. If Dad doesn't do much....

But there's usually an outdoor activity they can be encouraged into. With the right guidance. So much on offer these days.

My elder GS seems to spend half his weekends at some camp or other. He slings his hammock between two trees. With an overhead tarpaulin.

Try a different Scout troop.

If dad doesn't do much doesn't make it genetic. That's nurture, not nature.

Might be both.

There are more things in our genes than this world dreams of. Or something similar.

Try him on kayaking. Or trampolining.

My husband never did much physically, as he'd been diabetic since he was 11, and exercise wasn't encouraged in the 50s and 60s.
Our son and his partner go running, 5k, 10k and a few marathons.
Their 14 year old son feels as if he might get fat if he doesn't go running every other day at least, 5k minimum and quite often 10k. His sister doesn't like running, but she dances everywhere, even down to school and back.
That could be nature, but it's definitely nurture.

What about exercise games on the
W E Nintendo, I think you can buy second hand.
My DS was not into football and most sport but enjoyed table tennis and swimming
What about junior golf
There is also good old bribery
My DC always had a small amount pocket money from their GPs If they were well behaved (seems they always were ) and they got a bit extra for small achievements.(School work and sport).

Don't need to try a different scout troop they all do one evening a week anyway they love it but I m just saying it's only a couple of hours a week some kids aren't born to be Bear Gryliss there shouldn't have to be pressure to make them into one if its not their thing anyway he wears a lot of make up says my grandaughter scout who had a boat ride with him last year LOL

Bear Grylls put in a very brief apperance at the last camp DGS was at. Would not be at all surprised about the makeup. I don't think he's a good choice for Chief Scout.

All of the above are good ideas. But can I introduce the idea that he may be overweight because he doesn't like exercise and eats crap. And he likes it that way. He is the same person,thin or fat.

He may be in a growth spurt, or a phase. But what if he becomes an overweight teen who grows into an overweight adult?if I were you I'd focus on him- who he is and fostering a relationship with him rather than his size.

I agree with you there Jinglebells much too much of a 'celebrity' to be a Chief Scout got to say my granddaughter wasn't impressed at all .. I got put off when I saw some programme where he was making people stick tubes up their a** on camera and I thought he was a , * whoops nearly said a w word there

When my son was at Scout camp in the pouring rain and Bear Grylls arrived with a minder and an umbrella! My DS was overweight and very self conscious about playing sport. At age 13 he became more aware of what he was eating, got a bike and a paper round and the weight has dropped off. He has just joined a football team! When he was overweight I tried to encourage him to eat the "right" things but refused to put pressure on him as puberty is a difficult time anyway.

I would be concerned about him getting fat for his sake, it can have a negative impact on his confidence and health , but you can only encourage him to be active and not force the issue . A fitbit is a great idea , youngsters love anything techy and it will make him aware of how little he is moving! Things can change at this age but I doubt it if he is glued to a screen .

Trouble with a Fitbit is it records steps taken and disregards any other form of motion. Including scooters, bikes and skate boards. How many teens actually enjoy walking?

Although it might encourage a bit of movement. I might give mine to DGS2. I never use it.