How to understand the nutrition facts label
https://www.fda.gov/Food/LabelingNutrition/ucm274593.htm
美国FDA关于packaged food 营养标签的解读
健身的人一般准备食物都会很注意看nutrition facts label，某天在trader joe's 突发奇想，为什么同样的食物serving size不一样呢？120g和140g?
特此展开一番调查，有点意思的。
以及你看到的各种食品广告宣传用语都是什么样的使用标准，以下内容转载自网络：
What about nutrition claims?
Nutrition claims provide a snapshot about the amount of one specific nutrient in a food, such as fibre or fat. While nutrition claims are optional, they must meet government regulations before appearing on a package.
Here are some examples of common claims:
Source of Fibre
"Source of fibre" means the food contains at least 2 grams of fibre in the amount of food specified in the Nutrition Facts table. "High source of fibre" means at least 4 grams of fibre, and "Very high source of fibre" is at least 6 grams of fibre.
Low Fat
"Low fat" means that the food contains no more than 3 grams of fat in the amount of food specified in the Nutrition Facts table.
Cholesterol-free
The claim "Cholesterol-free" means that the product has a very small amount (less than 2 mg of cholesterol in the amount of food specified in the Nutrition Facts table) and it is also low in saturated fat and trans fat.
Sodium-free
A "sodium-free" claim means the amount of food specified in the Nutrition Facts table contains less than 5 mg of sodium.
Reduced in Calories
"Reduced in Calories" has at least 25% less energy (Calories) than the food it is being compared to ? most of the time, it’s being compared to the regular version of that food
Light
The term "light" is allowed only on foods that are either "reduced in fat" or "reduced in energy" (Calories). "Light" can also be used to describe sensory characteristics of a food, for example light tasting or light coloured.
新的问题来了：为什么酒精没有nutrition facts，只有alcohol percentage?
Why is alcohol exempt? The short answer is that, mainly as a legacy of Prohibition,alcoholic beverages aren't regulated by the FDA, but a different federal agency called the Alcohol and Tobacco Tax and Trade Bureau (TTB) — and this agency doesn't require nutritional labeling."
2013年，TTB迫于一些lobbying group以及medical researchers的压力，规定酒精饮品的nutrition label可以添加，但是并没有强制规定。根据John Hopkins 的一名研究人员Sara Bleich认为”不强制规定营养成分细节导致很多美国人对于自己从酒精中摄入的热量并不知情“。平均每天，美国人大概摄入400大卡的热量通过酒精的摄取。（当然对于我这种不能喝酒的人来说，自然没有这种烦恼）
从历史根源来说，自从禁酒运动之后，1935年联邦政府通过Alcohol Administration Act并且建立了TTB来征收合法酒精的消费税，没有在FDA管辖范围内的liquor以及wines也就逃脱了强制营养成分标识的命运，除了酒精成分低于7%的啤酒属于FDA管理，尤其是广告词中使用“low carb”类似用语的必须有label。
消费者保护群体和酒精制造商长达几十年的拉锯战从未停止，各说各的理，感觉TTB还是站在金主爸爸，AKA各位制造商这边的，所以喝酒的各位，看不到的label, 喝进去的东西，只有自己小心咯。
文章参考：https://www.vox.com/2014/11/12/7195573/alcohol-nutrition
