re: A friend of mine is getting disowned by some family members for divorcing wife that

His family already thinks he's a dick. He got a divorce. Now maybe he can see his kids on the weekend. That sounds way better than what I suggested.

"Hey honey, I was thinking about it, how about we cut out junk food in the house? You know we have the kids and I don't think it would be the best for them to always have access to it. Plus we can improve our diet and provide a great example for our kids."

Yeah that sounds super controlling. If you suggest that and she refuses to change or goes against what you feel is best for the family than it is no longer you leaving your wife of 10 years for being chubby but rather you felt she didn't value you or how you felt.