Best way to help my 10yo son lose weight without forcing him to cut back much on food?

Selective substitutn: Start with a lifestyle audit & identify the type & quantity of foods or beverages consumed on a regular basis.Learn the calorie value of these items & identify some that could be replaces with a low calorie but tasty item. For example:simply substituting a diet cola or crystal light for sugary drinks you can save about 100 cal/drink. Substitute 1/day & drop a pound a month.