for various reasons, including some anger management problems that were making him miserable, my son was highly motivated to try it at the age of 11.  Even then i bribed him with a video game he wanted if he would go 3 weeks eating only what I provided, which was of course all paleo.

When he saw that made a huge difference he was motivated to stay on plan, but the social difference was a big problem for him.  We compromised, borrowing a principle from rotation dieting and settled on every 4th day being "off-plan".  That way he could save his off-plan days if need be to coincide with known pizza parties, etc. He would stretch 4 days to 5 or 6 if an event was coming up.

This rotation worked equally well for him at controlling the rage, so he kept it up for a long time.

But by age 14 he was back to eating junk whenever he was out of the house.  All I can do about that is remind him, which is apparently of no effect against the lure of teenage girls sharing Skittles (are we all shocked <g>?)

At this point I would rather not ruin every evening with this battle, so I simply only provide paleo food at home and let it be his own business what he eats and drinks elsewhere.

I figure, he's going to rebel at this age anyway, thank heaven he's doing it over Dr Pepper rather than many other things he could be into as a teenager.  And there are benefits to even this limited paleo for him in the form of clear skin, and a very muscular body without weight lifting when his friends are getting either skinny or fat and are popping out in zits.

Kathleen