What's a way to encourage my obese son & grandson to lose weight and eat healthy?

Obesity in kids: To encourage them to eat right you need to set an example and do not give any foods that you do not approve of. Any weight loss even if miniscule , you should give them kudos for and encourage more family outdoor activities. If they watch a lot of tv or are on the computer a lot take away those things and plan outdoor events and weekly activities in advance and they have to adhere to the plan.