The Paradox of Spicy Food in Hot Climates
Consuming dishes that induce sweating in already warm weather might appear paradoxical. For decades, researchers have debated whether the act of sweating is the goal itself, or if the association between hot climates and spicy food is merely a myth rather than a biological adaptation. In 1998, an influential explanation emerged when researchers Jennifer Billing and Paul Sherman examined 4,578 meat recipes across 36 countries. Their findings indicated that recipes from nations with higher average temperatures tended to incorporate a greater quantity of spices, including those with antimicrobial properties.
The researchers suggested that spices may have historically helped preserve food from pathogens before refrigeration became commonplace, particularly in warmer climates where food spoils more rapidly. However, their study looked at spices in general—ranging from garlic and onions to oregano and chili—without specifically measuring the level of spiciness consumed by various populations.
Cultural Influences on Spicy Cuisine
Recent investigations have raised questions about this conclusion. A 2021 study published in Nature Human Behaviour analysed a significantly larger dataset, comprising 33,750 recipes from 70 cuisines that included 93 different spices. By considering the fact that neighbouring cultures often share culinary traditions, the researchers discovered that temperature did not account for variations in spice usage. Furthermore, the data did not support the notion that spices became popular mainly for the purpose of reducing foodborne infections.
In essence, the widely held belief that spicy food is prevalent in hot countries due to the preservative qualities of chili remains a hypothesis rather than a robust evolutionary explanation. Ruba Elhourani, a clinical dietitian and head of the nutrition department at RAK Hospital, states, “The popularity of spicy food in warm climates likely stems from a combination of cultural, agricultural, historical, and physiological factors. Chilies and many spices thrive in warm regions and have been integral to local cuisines for centuries.”
Rithuparna Raj, a food research and development technologist specialising in sensory evaluation, adds that the availability of chili might have led to repeated exposure, resulting in a culinary preference. “As chili was readily accessible in warmer regions, people grew accustomed to spicy flavours, making them a significant part of traditional cuisines.”
The Antimicrobial Properties of Spices
While many spices possess antimicrobial properties, various studies have shown that compounds found in chili and other spices can inhibit the growth of certain bacteria and fungi. However, this does not imply that adding chili to a dish provides sufficient protection against food spoilage or foodborne illnesses. “Although some compounds in chili may inhibit the growth of specific microorganisms and aid preservation, they cannot be relied upon as a standalone preservative,” notes Raj.
There is a popular theory suggesting that spicy food cools the body. Capsaicin, the compound responsible for the heat in chili, activates TRPV1 receptors involved in detecting potentially harmful heat. Although chili does not physically burn the mouth, the nervous system reacts as if it has encountered something hot, resulting in flushing, increased blood flow to the skin, and sweating.
Understanding the Cooling Effect of Sweat
“When sweat evaporates, it removes heat from the body and creates a cooling sensation,” explains Elhourani. However, stimulating the body’s responses to lose heat does not necessarily equate to a significant reduction in core temperature. In a small experiment conducted in 2000, seven men ingested capsaicin or a placebo before spending two hours in a chamber heated to 38°C with 50% relative humidity. Both trials resulted in increased core temperature, cardiac output, and oxygen consumption, while body mass and plasma volume decreased. Yet, none of these changes significantly differed between the capsaicin and placebo groups.
The only notable difference was a 0.4°C reduction in average skin temperature after ingesting capsaicin. The researchers concluded that, under the conditions tested, capsaicin did not enhance participants’ ability to regulate body temperature in heat. Moreover, sweating only cools the body when sweat can actually evaporate. Its effectiveness is largely dependent on humidity, clothing, and airflow. Producing more sweat in a humid environment may merely increase fluid loss without providing substantial additional cooling.
The Role of Spicy Food in Sensory Adaptation
“While spicy foods may create a subjective sensation of cooling through sweating, they should not be viewed as a primary strategy for coping with extreme temperatures. Proper hydration is far more crucial,” argues Elhourani. Interestingly, the consumption of chilies can alter the intensity with which heat is perceived. A 2023 study asked participants to rinse their mouths with a low-dose capsaicin solution twice daily for two weeks. At the end of the experiment, they reported a significant reduction in perceived heat.
However, this effect represents sensory desensitisation rather than an increased capacity to endure heat. “Those accustomed to very spicy food can tolerate a chili that would be too intense for someone who rarely eats such foods. But this does not mean that the chili no longer interacts with the receptors; rather, the sensory system becomes less responsive to the signal,” explains Raj.
The most compelling answer to the prevalence of chili in cuisines is also the least clear: chili spread through agriculture, migration, and trade before becoming entrenched in local traditions. People continue to consume it because taste is learned, recipes are passed down, and for those accustomed to heat, food without it may simply feel incomplete. Although chili can induce sweating, existing human data do not demonstrate that its consumption significantly protects the body against extreme heat. Additionally, there is no solid evidence that climate alone explains why some cuisines became spicier than others.