There are a number of explanations for why we have added spices such as chile peppers to our foods over the tens or hundreds of thousands of years that we have been cooking. They are:
–Spices make foods taste better.
–The "eat-to-sweat hypothesis"-eating spicy foods makes us cool down during hot weather.
–To disguise the taste of spoiled food.
–Spices add nutritional value to food.
–The antimicrobial hypothesis: spices kill harmful bacteria in food and aid in food preservation.
Which of these explanations are correct? Read my article about it, here.