they do dietary counseling with individuals for the most part,

他们为个人进行营养咨询
telling them about portions, and calories,

告诉人们关于每日摄入量和卡路里
and nutrients and things like that,

以及营养素等
so you'd think these folks would know a lot--

所以人们认为营养学家们懂得很多
they were asked to estimate the calories in, again common foods,

当他们被要求估算普通食物卡路里时
lasagna, hamburger with onion rings, tuna sandwich, etc.

像意面洋葱圈汉堡金枪鱼三明治
And what they found was they underestimated by 200-600 calories,

结果营养学家们把这些食物的卡路里
the calories in these foods.

低估了200到600卡
Again, you get a sense of how complicated this is.

你们体会到这个问题有多复杂了吗
If even the dieticians can't do it accurately

如果连营养学家们都无法精确估算
what in the world is the average going to do?

那么普通人究竟该如何去做啊
A lot of sciences rest on data that is flawed in some ways

许多依赖数据的科学常识是有瑕疵的