What is healthy when it comes to food? That’s a question that many people struggle to answer on a daily basis around the world. How much sugar, fat, carbs, and salt our bodies need has been the topic of debate for, well, pretty much forever, and constantly-shifting nutritional guidelines aren’t making things any easier to understand.

什么样的食品才算是健康食品？世界各地每天都有人受这一问题的困扰。身体所需的糖分、脂肪、碳水化合物和盐含量一直以来都是争论的焦点，而不断变化的营养指南并没有让事情变得简单。

Calories are, of course, the biggest factor in how much weight a person loses or gains, but how we get those calories can vary dramatically from person to person. Now, a new study suggests that eating so-called “ultra-processed” foods may be fueling the obesity epidemic and contributing to overeating.

当然，卡路里是一个人增重或减重的最大因素，但获取卡路里的方式却因人而异。现在，一项新研究表明，食用所谓的“过度加工”食物可能会加剧肥胖症，导致暴饮暴食。

The study, which was published in Cell Metabolism, focused on the eating habits of a group of 20 volunteers who agreed to follow specific eating guidelines for two weeks. The subjects selected for the study were considered “weight-stable,” meaning they had been maintaining their weight without any dramatic fluctuation.

这项研究在《细胞代谢》杂志上发表，关注20位志愿者的饮食习惯。这些志愿者同意连续两周遵循特定的饮食指南。研究员认为这些受试者“体重稳定”，也就是说他们的体重处于几乎持平状态，没有太大波动。

The group was randomly split into two groups, with one group eating a diet of unprocessed foods and the other eating the oh-so-convenient ultra-processed foods, or "junk food," as we often think of it.

20位受试者被随机分成2组，一组食用未加工食品，另一组食用方便过度加工食品，或我们俗称的“垃圾食品”。

“During each diet phase, the subjects were presented with three daily meals and were instructed to consume as much or as little as desired,” the researchers write. “Up to 60 min was allotted to consume each meal. Menus rotated on a 7-day schedule, and the meals were designed to be well matched across diets for total calories, energy density, macronutrients, fiber, sugars, and sodium, but widely differing in the percentage of calories derived from ultra-processed versus unprocessed foods.”

“在每一饮食阶段，受试者都是一日三餐，可根据自己的喜好多吃或少吃，”研究员写道。“每次用餐时间最多为60分钟。每隔7天会重复菜品，膳食的设计满足了人体所需的卡路里、能量密度、常量营养素、纤维、糖和钠，但过度加工食品和未加工食品的卡路里比例相差甚大。”

With no limitations placed on the number of calories any of the subjects were consuming, the participants ate until they were satisfied and full. Those in the processed diet group could eat chips, candy, cereals, and other energy-dense foods, while the others consumed cooked whole vegetables, minimally processed rice, and fruit.

研究员未对受试者消耗的卡路里量设定限制，所以受试者可以一直吃到心满意足。加工饮食组的受试者可以吃薯片、糖果、谷物和其它能量密集的食品，而另一组则摄入烹饪过的蔬菜、加工较少的大米和水果。

On average, those who were given the ultra-processed diet ate just over 500 more calories than those who ate the unprocessed foods. The ultra-processed group gained an average of two pounds during the two-week experiment, while the unprocessed food group lost roughly the same amount.

平均而言，那些食用过度加工食品的人比食用未加工食品的人多摄入了500多卡。在为期两周的实验中，食用过度加工食品的分组平均增加了2磅，而食用未加工食品的分组大约瘦了2磅。