I need to know how to lose weight. i've had 3 knee surgeries so it's hard to work out?

Diet & exercise.: Low impact aerobic exercise and mild calorie restriction with healthy food choices would be the rule of the day. There should be some of aerobic exercise your Orthopedist will allow. Low caloric density foods. Low fat. High fiber.

Some Basics: Focus on what you eat, when you eat, and how much you eat, along with aerobic exercise.Take in less calories each day than you burn off exercising. Take food seriously and learn about the amount of calories you are eating and the kinds of nutrition your putting in your body. Eat good calories. Bikes (seat up high or back far), swim, ellipticals, rowing machines. bigger breakfast, small dinner.

Swimming or: wwater exercise would be good. Balanced diet with portion moderation will help.