Teenage weight loss question?

What's a god way for a 13 year old to loose wight? Normally she eats all bran cereal with skim milk for breakfast, protein shake and a cereal bar for lunch yogurt for a snack and spaghetti with meat for dinner. What should be improved? She is about 160 and 5"3. She'd like to loose 40pounds. She doesn't have much time to exercise so what do you recommend? And please no "You should try axelis! The weight loss magic pill!"