Traditional Chinese Medicine and Ayurvedic medicine both take into consideration the hot or cold element of foods and beverages. Ayurvedic medicine advises to drink hot water in the morning to stimulate digestion. In Western medicine, this is less of a concern, but maybe it should be considered, especially for those with digestive problems.
Eating and Drinking Together
To drink a beverage while eating is really not necessary, and it could upset digestion in general. Whether the drink is hot or cold, it is better to save it for after you have eaten completely. According to Raw Food Explained.com, the beverage interferes with digestions because the digestive liquid and enzymes get carried out with the beverage rather than staying in the stomach. Also, taking a swig of a beverage might wash down food that has not been properly broken down through chewing and mixing with saliva in the mouth.
Cold Beverages Slow Digestion
According to Susan E. Brown, PhD, cold foods and beverages slow down the rate of digestion because they must be "heated up" before proper digestion can take place. Cold beverages are removed from the stomach more quickly. Those at room temperature stay in the stomach longer. That is why marathon runners try to hyperhydrate and drink cold water before a race -- to prevent from becoming dehydrated. Yet, if cold liquids move through at a fast rate, they do not aid digestion.
Ayurvedic medicine suggests that you boil milk before drinking it because cold milk is hard for anyone to digest properly. Milk is mucus-producing for all, takes additional steps to digest and in infants, it actually gets curdled in the stomach by a particular enzyme to make it more digestible.
Soda or carbonated beverages can cause gas and bloating in the stomach. Very cold beverages, especially those with a lot of sugar, might cause uncomfortable feelings and even nausea when consumed on an empty stomach. Although cola and ginger ale do help with symptoms of nausea, they are not recommended on a regular basis due to their high sugar content and other added ingredients. When you drink them for an upset stomach, room temperature beverages are better.