As summer heat cranks up, our appetites may cool off

Summer is in full swing, and some parts of the U.S. have already experienced record-high temperatures. 暴露在极端高温下——与天气有关的死亡的主要原因——会导致中暑, heat stroke and added strain on the heart and kidneys, 加重心血管疾病和呼吸系统疾病等潜在疾病.

But extreme heat can also have a more subtle effect on the body, influencing how much and what people want to eat. In short, as temperatures rise, appetites may drop.

Researchers say there's a reason for that.

High temperatures, low appetites

消化食物和储存营养物质需要能量，而能量会产生热量. Allison Childress, 她是一名注册营养师，也是位于拉伯克的德克萨斯理工大学营养科学系的副教授.

她说:“在寒冷和炎热的天气里，卡路里的摄入量有明显的不同。. "A calorie is a measure of heat. 在寒冷的环境中，你需要燃烧卡路里在体内产生热量. 人们在炎热或温暖的环境中不会摄入那么多的卡路里，因为这会使身体升温."

虽然温度和食欲之间的联系机制还没有被完全理解, 动物研究表明，较高的环境温度可能会降低肠道激素胃饥饿素的产生, which stimulates hunger in the brain, said Dr. Gordon Fisher, 他是阿拉巴马大学伯明翰分校教育与人文科学学院和人类研究系的运动机能学教授和研究助理院长.

“大脑和胃之间的体温调节过程可能在调节食物摄入方面发挥作用," he said. “但我们还不能确定一个确切的机制来解释这一点."

During a heat wave, eat this, not that

专家表示，有些食物比其他食物更能产生热量，这不仅仅是因为它们辣.

When temperatures rise, 人们不太可能渴望那些需要更多消化努力和增加身体热量产生的食物, Childress said. “但这并不意味着天气炎热时身体不需要蛋白质或纤维." To get the recommended amounts, 她建议人们在一天中更频繁地少吃两种食物.

费舍尔说，一般来说，要避免高热量的食物.

专家表示，当气温上升时，保持水分一直很重要，尤其重要.

Water is best for hydration, Childress said. But some people don't like its taste. She suggests adding flavor with a slice of orange or cucumber.

“低脂牛奶是一个不错的选择，因为它是一种可以冷喝的液体，而且含有很多营养," she said.

Fisher warned against drinking alcohol or beverages high in caffeine. 他说:“它们都有脱水作用，会导致水分流失增加。.

But moderate amounts of caffeine are fine, Childress said.

“不加糖的冰咖啡和冰茶可以补水，只要你适量饮用," she said. "Any fluid is better than no fluid."

Beverages aren't the only source of hydration, Fisher said. Foods can provide about 20% of the body's fluid intake.

"Melons, berries, lettuce, celery, tomatoes, cucumbers, soups, 冰沙和酸奶只是少数几种富含水分的食物，还能起到降温的作用," he said.

“水果和蔬菜等含有大量水分的食物能给我们降温效果，而且我们通常是凉着吃的," Childress said.

但她说，仅仅因为食物是冷的，并不意味着它就能帮助身体降温.

"A popsicle or cold beverage can give immediate relief, but if there are calories in those things, 我们最终消化了这些卡路里，它们最终会略微提高体温," she said.

Heat and food insecurity

Not only can extreme heat make people less interested in eating, it can also make it harder to grow and obtain food.

“一般来说，热浪会导致农业增长放缓，导致食品价格上涨," Fisher said.

而且，他们会让人们更难到达卖食物的地方.

Heat waves not only affect the food supply, they "can also affect the desire to leave the house," Childress said. 对于缺乏交通工具的人来说，长距离步行变得更加困难.

"People who live in food deserts, far away from the food, are a lot less apt to go out to shop when it's really hot outside," she said. "They skip it. Food insecurity can be worse in extreme weather. It's also a problem when it's very, very cold outside."

柴尔德里斯建议在天气预报显示天气炎热时储备食物，以减少外出的需要.