In ancient times, Tibetans on the Qinghai-Tibet Plateau primarily consumed high-fat, high-sugar foods like beef, mutton, cheese, butter, and highland barley to adapt to their natural environment. Dark tea became essential for balancing and decomposing grease, as well as supplementing vitamins. Hence, there is a Tibetan proverb: "One day without tea leads to stagnation, three days without tea leads to illness."

Promoting digestion and resolving accumulation can be considered the healthcare function of dark tea. Because dark tea generally uses relatively coarse and old raw materials, coupled with a longer pile-fermentation process during production, the leaves become dark brown or blackish-brown in color. This is why it is called the "coarse grain" among teas.

In fact, the coarse leaves used for dark tea have unique advantages compared to the so-called "high-grade teas" made from tender leaves. It's similar to how modern people have started eating coarse grains; its nutritional benefits lie entirely in this "coarseness".

Benefits of "Coarse Grain":

1. Coarse old leaves are rich in木质fiber and tea polysaccharides. They can increase gastrointestinal peristalsis and repair intestinal function.

2. Coarse old leaves contain abundant tea pigments. Theaflavin is an effective free radical scavenger and antioxidant, with benefits such as beautifying the skin, anti-cancer, anti-mutation, antibacterial, and disinfectant effects.

3. Coarse old leaves are rich in proteins and specific amino acids. Theanine can help inhibit elevated blood pressure.

4. They contain various minerals such as sodium, potassium, iron, copper, phosphorus, and fluorine.

Moreover, dark tea is a relatively mild tea. It not only aids digestion but also has a much lower theine content compared to green tea. Drinking some in the evening doesn't typically cause worry about sleeplessness.

Therefore, for modern people who often consume rich foods (high in fat and meat), and where much of the fat and calories are stored in the body making weight gain likely, drinking more dark tea in summer when the digestive system is under greater burden can not only eliminate grease but also cleanse internal waste, protect blood vessels, and prevent obesity.