What are some tips for obese teenagers to loose weight?

Set sensible goals: Successful dieting requires that a person stick to a plan for months or years, so easier goals & small milestones are good. He must be happy with the foods he gets to eat, so severe calorie restriction is usually unsuccessful. One can cut back on calories enough to lose 1-2 pounds a week, and he will be more likely to stay with that modest type of plan. One-two pounds a week is 50-100 pounds/year!

Exercise and Diet: These always work just difficult to maintain. Definitely you need to increase activity and decrease the sedentary lifestyle. Avoid the typical fast food places. Eat healthy home cooked meals. Eat together as a family.