Most Americans eat ultraprocessed foods every day.大多数美国人每天都吃超加工食品。 These are foods that you cannot make at home because they contain flavors and chemicals that change the taste or feel of the food.超加工食品无法在家制作，因为它们含有改变食物味道或口感的调料和化学物质。 Such food may also go through preparation methods that are not possible in a home kitchen.这种食品可能还要按照在家庭厨房中不可能实现的方法进行制作。 They are usually high in salt, sugar and fat.它们通常高盐、高糖和高脂肪。 Americans may eat them in the form of sugary cereals at breakfast, frozen pizzas at dinner, and in-between bites like potato chips, sodas and ice cream.美国人摄入它们的方式可能是：早餐吃含糖谷类食品，晚餐吃冷冻披萨，这两餐中间吃薯片、苏打水和冰淇淋。 Ultraprocessed foods make up about 60 percent of the American diet.超加工食品约占美国饮食的60%。 For children and teenagers, it is even higher -- about two-thirds of what they eat.对于儿童和青少年来说，这一数字甚至更高——约占他们所吃食物的三分之二。 Scientists have connected eating ultraprocessed foods to poor health results.科学家已经将食用超加工食品与健康状况不佳联系起来。 Being overweight is one such result and that may lead to diabetes and heart disease.超重就是这样的健康状况，可能会导致糖尿病和心脏病。 Other possible health risks include depression and dementia.其他可能的健康风险包括抑郁症和痴呆症。 One recent study suggested that eating these foods may raise the risk of early death.最近的一项研究表明，吃这些食物可能会增加早逝的风险。 Nutrition science is complex, though, and most research so far has found connections -- not proof -- regarding the health effects of these foods.不过，营养科学很复杂，而不是证据。到目前为止，大多数研究都只发现这些食物对健康影响的联系——而不是证据。 Food manufacturers argue that processing increases food safety and food supplies.食品制造商认为对食品进行这种加工可以提高食品安全和食品供应。 They say it also offers a low-cost, easy way to provide a diverse and nutritious diet.他们说，这种加工方式还提供了一种低成本、简单的方法来提供多样化和营养的饮食。 The Associated Press asked several nutrition experts to explain these foods so that people can make informed choices.美联社请了几位营养专家来解释这些食物，以便人们做出明智的选择。 Most foods are processed, whether it is by freezing, grinding, fermentation, pasteurization or other means.大多数食品都经过加工，无论是通过冷冻、研磨、发酵、巴氏灭菌还是其他方式。 In 2009, Brazilian epidemiologist Carlos Monteiro and his team first proposed a way to classify foods by how much they are processed, not by their nutrient content.2009年，巴西流行病学家卡洛斯·蒙泰罗及其团队首次提出了一种食品分类方法——根据食品的加工程度而不是其所含的营养成分。 This is called the Nova classification system.这被称为NOVA分类系统。 It is used by international bodies like the World Health Organization.世界卫生组织等国际机构都采用这一分类系统。 Kevin Hall is a researcher who studies metabolism and diet at the National Institutes of Health.凯文·霍尔是美国国立卫生研究院研究新陈代谢和饮食的一名研究员。 He said that foods at the top of the Nova four-level scale are foods prepared with industrial processes and ingredients他表示，在Nova四级食品等级中，最高等级的食品是通过工业过程和工业配料制作而成， such as additives, colors and preservatives that you could not use in a home kitchen.例如家庭厨房中无法使用的添加剂、色素和防腐剂。 "These are most, but not all, of the packaged foods you see," Hall said.霍尔说：“这些是你看到的大多数包装食品，但不是全部。” Not all processing is unhealthy, Hall noted.霍尔指出，并非所有的加工都是不健康的。 Whole-grain bread, yogurt, tofu and infant formula are all highly processed, for example.例如，全麦面包、酸奶、豆腐和婴儿配方奶粉都是高度加工食品。 But they are also nutritious.但它们也都很有营养。 Still, many studies suggest that diets high in ultraprocessed foods are tied to poor health results.尽管如此，许多研究表明，含有大量超加工食品的饮食与健康状况不佳有关联。 The exact cause is still unclear.具体原因尚不清楚。 Hall and his partners carried out a small study with 20 people who came to live at a health center for a month.霍尔和他的伙伴们对20个人进行了一项小型研究，这20个人在一家健康中心住了一个月。 Some of the people ate ultraprocessed foods, while others ate unprocessed foods.其中一些人吃超加工食品，而另一些人吃未加工食品。 The two groups got the same amount of calories, sugar, fat, fiber and nutrients for two weeks.这两组人在两周内摄入了相同数量的卡路里、糖、脂肪、纤维和营养物质。 They could eat as much as they liked.他们可以想吃多少就吃多少。 When people ate the diet of ultraprocessed foods, they took in about 500 calories per day more than when they ate unprocessed foods, researchers found.研究人员发现，当人们食用超加工食品时，他们每天比食用未加工食品时多摄入约500卡路里的热量。 They gained an average of about 1 kilogram during the study period.在研究期间，他们（食用超加工食品的人）的体重平均增加了约1公斤。 People who ate only unprocessed foods for the same amount of time lost about 1 kilogram.在相同时间内只吃未加工食品的人减掉了大约1公斤的体重。 A new study is currently taking place and its results should appear next year.目前一项新研究正在进行中，其结果将于明年公布。 Dr. Neena Prasad is director of the Bloomberg Philanthropies' Food Policy Program.尼娜·普拉萨德博士是彭博慈善基金会“食品政策项目”的负责人。 She said such foods are often made to be both low-cost and very tasty.她说，这类食品通常既便宜又非常美味。 "You just can't stop eating them," Prasad said.“你就是没法不吃这类食品，”普拉萨德说。 She said she believes leaders have enough facts to change policies.她说，她相信领导人有足够的事实依据来改变政策。 This could mean raising taxes on sugary drinks, limiting salt in these foods and controlling how advertisers sell the foods to children.这可能意味着提高含糖饮料的税、限制这些食品中的盐以及控制广告商向儿童销售这些食品的方式。 Earlier this year, Food and Drug Administration Commissioner Robert Califf told a group of food policy experts that ultraprocessed foods are a complex subject.今年早些时候，美国食品和药物管理局局长罗伯特·卡利夫告诉一群食品政策专家，超加工食品是一个复杂的问题。 However, Califf said, "We've got to have the scientific basis and then we've got to follow through."然而，卡利夫说：“我们必须有科学依据，然后我们才能坚持到底。” Aviva Musicus is science director for the Center for Science in the Public Interest.阿维娃·穆斯克斯是公共利益科学中心的科学主任。 She said buyers should check information printed on food containers and make choices based on the current U.S. Dietary Guidelines.她说，购买者应该检查食品包装上的信息，并根据现行的《美国居民膳食指南》做出选择。 "We have really good evidence that added sugar is not great for us.“我们有有力证据表明添加糖对我们没有好处。 We have evidence that high-sodium foods are not great for us," she said.我们有证据表明高钠食物对我们没有好处，”她说。 Musicus added, "We have great evidence that fruits and vegetables which are minimally processed are really good for us."穆斯克斯补充说：“我们有重要的证据表明，经过最低限度加工的水果和蔬菜确实对我们有好处。” I'm Jill Robbins.吉尔·罗宾斯为您播报。