The hormone CCK acts like a watchman right at the front door of a building. Secreted from the small intestine wall it signals the brain that food is on it's way from the second it spots proteins or fats coming in it's territory. It's the hormone that signals your brain to feel full and stop eating. CCK (Cholecystokinin) also has a defense mechanism around eating too much protein and fat, one of it's other jobs is to signal your gallbladder to contract and secrete bile to help absorb fats. (if you eat too much fat it will make you feel sick to your stomach and may even make you throw up.)
But this is not the case for carbs.
People often like eating carbs because it gives them a feeling of a light meal (like fat free yogurt for breakfast). That light feeling happens because carbs are like ninja's that sneak past the guard, they go quickly through the stomach and into the intestinal wall without even being caught.
Carbs sneak their way in. They enter the blood stream quickly where insulin is secreted, serotonin is produced, sugars leave the liver and the brain finally gets a message; "Food is here, need to start feeling full" And by that time you ate the whole row of cookies. Just think about it, how many hard boiled eggs can you eat for breakfast? Now how much cereal can you eat?
So when it comes to being hungry and having cravings, make sure to eat meals with protein and fats and not only carbs.
