It is not advisable to engage in rigorous exercise (like swimming, running) after a meal because it directs blood flow away from the digestive area to the skin and to the muscles in your arms and legs. So, if your food is half-digested, you can end up feeling nauseous.

But walking after meals is a recommended practice because doing so stimulates the stomach and intestines, thus causing food to move through the digestive system more rapidly

It takes approximately 20 mins from the time you start eating for your brain to send out signals of fullness. Leisurely eating allows ample time to trigger the signal from your brain that you are full. And feeling full translates into eating less.

We feel sleepy after a meal because our digestive system needs more nutrients to digest the food. Since these nutrients are absorbed from the blood, digestion diverts blood flow to the stomach, reducing the blood supply to the brain. When the blood supply to the brain is low, we will start to feel sleepy.

We salivate when we see sour food. The sight of sour food triggers our brain to send messages to the salivary glands inside our mouth to secrete saliva. Our salivary glands react most strongly to sour food, which explains why we drool.

Our stomach rumbles when we are hungry. That’s because after the food is sent to the small intestine, some of the digestive juices and air that is swallowed with the food are left behind in the stomach. After some time, our stomach starts to expand and contract. As the air inside the stomach moves about, it causes our stomach to rumble, setting off hunger pangs.

We burp after drinking a soft drink. A soft drink contains carbon dioxide. When we drink it, the carbon dioxide goes into our stomach as well. But, our stomach is unable to absorb the gas. Also, since the temperature in our stomach is higher, the carbon dioxide cannot stay for long. Very soon, it will be forced out through the mouth and this causes us to burp.