Your body is pretty smart. It identifies a lack of nutrition in your diet, ie not enough protein for you to work out, and causes you to crave those things to replenish itself.

Your particular problem, if you still want to be a vegetarian, can be managed by, obviously, eating more protein. You can try nuts, cereals, lentils, beans. Some vegetarians I know eat eggs.

Of course, if you want to get buff quick, a balanced diet of carbs, proteins and fats will most efficiently give you the best results.

I definitely know what you are talking about. I actually went through the EXACT same thing when I was vegetarian for almost a year. At first I was following a low fat diet with lots of greens and healthy grains and towards the end I too started eating less good for you foods and larger portions. I just never felt satisfied. I would be hungry so soon after eating a huge meal even if it was filled with protein. I started snacking on nuts and still not satisfied. I'd be hungry within an hour of my meals and have sugar cravings almost right after eating. I couldn't continue as a vegetarian towards the end because my cravings for meat, particularly steak, got so strong.

I started seeing an acupuncturist for other reasons (fatigue) and spoke with a nutritionist and they both recommended I eat red meat. As soon as I started eating beef (organic variety!) I felt a huge difference in my energy levels and satisfaction. I no longer get sugar cravings and have actually been successful at cutting out refined sugar from my diet! The nutritionist told me these two things were linked. Anyway long story short I feel so much better now if I make sure I have protein at every meal. That means not oatmeal for breakfast but eggs! Lunch is meat (red meat really does it for me as opposed to chicken) with greens and dinner is some kind of legumes and rice for complete protein with veggies! What Mame said about balance is totally true but some people need more protein. I know this because I have tried going back to a vegetarian diet since and all those symptoms reoccured. It just doesn't work for me! I am definitely a protein type!!

it's nice to know i am not the only one who actually went through this. i felt so stupid that i would crave peanut butter especially when i got really hungry. now that i am eating eat again, my body has become easier to read. what i mean is before when i was a vegetarian, my cravings were for something heavy like peanut butter and with sugar, but when i ate it i wasnt satisfied, even when i was full. fo the longest time i thought i had a eating problem because i didnt want to stop eating. after every meal i wasnt satisfied. but now i when i eat some chicken or fish i feel fine. i dont have the urge to keep on eating. and i think my stomach was stretched before when i was eating bigger portions, so when i started eating meat again i was slowly beginning to notice my portions becoming smaller. it's so nice now not to have food on my mind anymore and a relief that i dont want to keep on eating even after i have eaten a meal.