Would I loose weight if I just had soup as a diet?
If you eat soup only you’ll lose weight, but you won’t actually lose fat around your body unless you do specific exercises. Talk to a personal trainer at a gym. After you lose the actual numerical value in weight, your metabolism will drop to a level so low, that when you resume you normal diet or a diet which is similar to your original, your weight will go back to what it is now. Like I said, just pop into a gym and ask if you can talk to a personal trainer about this, also ask about metabolism as your knowledge on this area is lacking.