One study asked healthy participants to eat pizza until they felt full. Then on a separate day to eat pizza until they couldn't anymore. They ate twice as much as on the first take, suggesting that when you feel full, you're probably only half full.

Blood samples were also taken at regular intervals to see how the body was coping. Despite eating twice as much food, there was only a small increase in blood sugar and blood fat levels.

• Studies revealed that in physically active and healthy people, the body is able to control the sugar and fat in the blood after a big meal by working a bit harder than usual to regulate metabolism.
• Hormones released from the gut and pancreas help the body to regulate blood sugar le...