Thailand is a diverse country and geographically divided into four distinct regions: Central (Bangkok), Northern (Lanna), Northeastern (Isan) and Southern. Thai food varies from region to region because of geography and history. In the West, most Thai restaurants serve Central (Bangkok) style cuisine.
The Central region is largely delta country, dominated by the Chao Phraya River, and with rich soil. Southern Thailand is peninsula country, with the Andaman Sea on one side and the Gulf of Thailand on the other. The North is cool and mountainous. Northeastern Thailand is a vast plateau and flanked by the Mekong River. Each region has its own distinct ethnic peoples, speaking their own dialect, practicing their own customs and having their own culinary traditions.
In the Central region, known for its sheer inventiveness, food is mainly hot, salty, sweet and sour. Steamed jasmine rice is served with different types of Nam Prik (chili dipping sauces) and soups. Tom Yum Goong (shrimp soup with lemon grass, lime juice and galangal) is a favorite dish. Prepared dishes usually contain many condiments and dried spices. the sheer inventiveness of the fertile Central region.
In the Northern region, around Chiang Mai, the land is mostly jungle-covered mountains and valleys. Historically this area is the home of the Lanna Thais, whose former capital was Chiang Mai. Northern Thai traditional food is mild or hot, salty and sour, but rarely sweet. Sticky rice (glutinous) is commonly served with steamed vegetables, chili dipping sauces (Nam Prik Noom and Nam Prik Ong), soups and Northern-style curries. The North is also well-known for Naem, a sour sausage made of fermented minced pork, wrapped and steamed in banana leaf. Lanna food is traditionally eaten at a small table called Kantoke table or tray made of oak in the Chiang Mai area. Diners sit on straw mats around the table, eating communally.
The Northeastern region, also known as Isan, the cuisine is simple with the herby, earthy recipes. Food, traditionally served on a table made from bamboo or rattan, is hot, salty and sour. Papaya salad (Som Tum), sour chopped meat salad (Koi), and sour minced chicken, beef, or pork salad (Larb) are favorites. Many condiments are used but not many dried spices in this region. Meals are based on sticky rice and a strong paste called Nam Prik Pla Ra (spicy dipping sauce of fermented fish and chilies) accompanied by raw wild and cultivated vegetables and herbs.
In the Southern region, food is renowned for being strong in taste, very hot, salty and sour. Spicy curries are eaten every day, especially coconut curry and sour curry. Generally, Southerners have more fish than meat, because the region is close to the sea. The most common dipping sauce is Nam Prik Kapi, eaten with raw vegetables and crispy fried fish. This dipping sauce is prepared with the best quality shrimp paste, fresh chilies, a bit of palm sugar and fresh lime juice.
It is therefore travelling in Thailand is also a culinary adventure of discovery to experience very different styles of cooking in the country, where there is such a tremendous variety of foods available. All this diversity has come together under the general heading "Thai food".