Why it can be hard to stop eating even when you're full

为什么已经吃到撑但嘴巴还是停不下来 

All foods are not created equal. Most are palatable, or tasty to eat, which is important because we need to eat to survive. For example, a fresh apple is palatable to most people and provides vital nutrients and calories. 

并非所有食物都是生来平等的。大多数食物都美味可口，这一点十分重要，因为人需要吃东西才能活下去。例如，对于大多数人而言，一颗新鲜的苹果不仅汁多味美，而且还能提供重要的营养素和卡路里。 

But certain foods, such as pizza, potato chips and chocolate chip cookies, are almost irresistible. They're always in demand at parties, and they're easy to keep eating, even when we are full. In these foods, a synergy between key ingredients can create an artificially enhanced palatability experience. Researchers call this hyperpalatability. Eaters call it delicious. 

但某些食物，例如披萨、薯片和巧克力曲奇饼干，却令人无法抗拒。聚会时总能看到它们的身影，而且即便在已经吃撑的情况下，也还能再吃一点。在这些食物中，关键成分间的协同作用可创造出一种人为增强的口感。研究员将其称为超美味性，大胃王称其为美味可口。 

Initial studies suggest that foods with two or more key ingredients linked to palatability — specifically, sugar, salt, fat or carbohydrates — can activate brain-reward neurocircuits similarly to drugs like cocaine or opioids. They may also be able to bypass mechanisms in our bodies that make us feel full and tell us to stop eating. 

初步研究表明，含有两种或多种调味成分（特别是糖、盐、脂肪或碳水化合物）的食物可激活大脑的奖励神经回路（与可卡因或阿片类药物的作用类似）。这些食物或许还能避开我们的身体机制，而这种机制会提醒我们饱腹，不需要再度进食。

Our research focuses on rewarding foods, addictive behaviors and obesity. We recently published a study with nutritional scientist Debra Sullivan that identifies three clusters of key ingredients that can make foods hyperpalatable. Using those definitions, we estimated that nearly two-thirds of foods widely consumed in the U.S. fall into at least one of those three groups. Foods that are easily accessible and cheap are everywhere in our society. Unsurprisingly, eating them has been associated with obesity. 

我们的研究集中关注奖励食物、成瘾行为和肥胖。近期，我们与营养学家黛布拉·沙利文（Debra Sullivan）合作发表了一项研究，确定了使食物变得超级美味的三类关键成分。通过定义，我们估计全美三分之二的美食都在这三类成分之列。便宜易买的食物到处都是，而食用这些食物与肥胖有关也就不足为奇了。

Documentaries in the last 15-20 years have reported that food companies have developed formulas to make palatable foods so enticing. However, manufacturers typically guard their recipes as trade secrets, so academic scientists can't study them. Instead, researchers have used descriptive definitions to capture what makes some foods hyperpalatable. For example, in his 2012 book, David Kessler, former Commissioner of the U.S. Food and Drug Administration (FDA), wrote: 

过去15至20年的纪录片报道，食品公司已研发出使美味食品变得诱人的配方。但通常情况下，制造商会将这些配方视作商业机密加以保护，因此学术科学家无法对其展开研究。因此，研究员根据这些描述性定义来探究食物口感超赞的原因。例如，2012年，美食品药品监管局（FDA）前专员戴维·凯斯勒（David Kessler）在其著作中写道： 

"What are these foods? .... Some are sweetened drinks, chips, cookies, candy, and other snack foods. Then, of course, there are fast food meals — fried chicken, pizza, burgers, and fries." 

“哪些食物属于这一范畴呢……。含糖饮料、薯条、饼干、糖果和其它休闲食品。当然，快餐食品—炸鸡、披萨、汉堡和薯条都属于这类食物。”