So there's a disincentive to buy the salad.

可以看出快餐店都在抑制色拉销售
If you look at McDonald's dollar menu what can you buy for $7.00

看7元能在麦当劳的一美元菜单理买什么
that that salad would cost, and have $.38 left over?

这等于沙拉的钱还富余0.38元
Well here's an example,

举例说
you could buy any of those things for the same $7.00.

你可以花同样的钱购买图上任意一组
If you've got a hungry family, or you're hungry yourself,

如果你的家人或是你自己都很饿
and you don't have a lot of money, and you need to fill up,

但你没足够的钱又急于填饱肚子
what are you going to buy if you have $7.00?

你会用仅有的7美元买哪样呢
Now, the government's not helping here.

政府这会儿帮不上忙了
There are incentives across all parts of the food supply.

整个食物供应链中存在奖励机制
For example, here are the amount of money per quart,

比如这是每夸脱的售价
per quart that various beverages cost:

每夸脱不同饮料的售价