Portion control is essential for taking off weight and keeping it off. Healthy foods, like nuts, eaten in mass quantities will still pack on the pounds. Moderation is the key for a healthy lifestyle.
One food where we tend to go overboard with portions is pasta; a portion of cooked pasta is one cup, about the size of a light bulb. Go with whole wheat pasta too. You can have your cake and eat it too, but just not everyday and not the whole cake.