How to drop weight easily and keep it off?

Okay so I'm 17 years old and about 6 feet tall and weigh about 200 pounds. Some people may say thats fine but I know I could loose like 20 to 30 pounds cause I'm a little chunky. My dad told me if I do atkins basically just don't eat carbs and I work out the weight will come right off like in 2-3 weeks. My only problem is I don't know if it'll work and I don't have much motivation to work out. Like it's really really easy for me to say imma work out tomorrow and actually plan on it but then when the time comes I'm like nahh I'll do it later. Any advice on motivating myself too?