I'm constantly hungry, within 30-40 minutes after a good meal I get hunger type pain. I am vegetarian and exercise regularly. If I don't eat I get weak and light headed.?

Inadequate Diet ? John, it sounds as if your diet may be inadequate in terms of protein which is often a problem area for many vegetarians. Also you may benefit from more fat and complex carbs in your diet as well. Your symptoms could also be hypoglycemia as well. If you are a true vegan it is difficult to get enough protein especially. Lacto-ovo is much easier to get appropriate protein intake.