Many consumers have noted that Thai food, and Asian foods in general, can be intensely spicy. Chilies create the spicy kick of Thai food, and if you are eating at a cooperative Thai restaurant, they can usually moderate or increase this ingredient on request. There are a number of reasons for this spiciness including preservation of unstable ingredients and personal taste, and you may find yourself learning to enjoy it over time.
Thai food is based on four core flavors: hot, sour, salty, and sweet. Each dish strives to strike a balance between these four elements, and many dishes incorporate soured foods like fish paste, salty ones such as soy sauce, sweet ingredients such as fresh fruit, and chilies for heat. Chilies were introduced to Thailand in the 1600s and quickly adopted, as they were across most of Asia. This often incendiary ingredient is used in fresh, dried, and pickled forms, depending on the cook and the type of dish.
Unlike other Asian cuisines, Thai food has a heavy focus on fresh ingredients, and less dried, preserved things. Thai curries usually feature fresh vegetables in a coconut milk broth with lemongrass, galangal leaves, or basil. The final touch to the fresh, zesty curry is a shot of heat, provided by chilies which may be seared in the wok before the curry is assembled or ground with other spices such as tamarind to form a curry paste. The heat of Thai food adds to the intensity of the experience and the flavor.
Some Thais believe that hot food has health benefits. Certainly it can clear out the sinuses, but heat is also an element in traditional Chinese medicine, which is practiced in various forms all over Asia. Too much heat can be unhealthy, but heat can also be used to correct systemic health problems which result from an excess of cold. Chilies can also help to boost the immune system and fight off illnesses, and have been shown to improve cardiovascular health.
Using heavy spices to preserve meats and fish is common because the chilies will stave off rot. Furthermore, if the meat does go slightly off, which is sometimes a deliberate choice in Thai food, the chilies will prevent uncomfortable intestinal symptoms because they kill organisms which cause food borne illness. For this reason, many hot climates have very spicy foods to ward off food borne illness, and travelers in areas with minimal hygienic practices would be wise to eat spicy foods along with the locals. Thailand is hot and muggy, ideal conditions for growing bacteria, so Thai food is hot and spicy as a preventative.
The spiciness of Thai food is an integral part of a delicious culinary tradition. If you are not familiar with spicy foods, ask restaurants to tone down the spices so that you can learn to appreciate the dishes, and gradually increase the amount of spices in your food so that you can grow to love mind-blowingly spicy foods. In addition to being a new culinary experience, it will also allow you to win chili pepper eating contests, a valuable skill in some nations.