This is good advice for your friends and family, but a bad answer to the question. "How can we solve the obesity epidemic? Stop eating so much and get some exercise." Well sure, but this misses the big picture. We built a social infrastructure that encourages a sedentary, solitary life. We shouldn't be confused by physical and emotional health implications. We can expect some people to be proactive about it, but we can't expect that of everyone.
I guess we need to delete the internet and tv from existence.
I think that the more people getting out and putting effort in the better, it helps create a knock on effect.