Why was 点 used in this sentence?
不饿？好吧，那你少吃点。(The translation given by the site was : You are not hungry?OK, then eat less.)

Question

Why was 点 used in this sentence?
不 饿 ？ 好 吧 ， 那 你 少 吃 点 。(The translation given by the site was : You are not hungry?OK, then eat less.)

Answer

I shouldn't have said that

Answer

I don't think so. Personally, I agree with three other guys. Here 点 is a measure word which is short for 一点 and it means a little, a bit, tiny amount. Here 少 is a verb which means reduce or weaken or make it less. So definitely the translation" Eat less" is correct. 
Besides, ”只吃了一点点“means eat a little.  I'm should have said that, but Bear234's English is just not as good as his Chinese.
e.g.
喝点水（drink a little)
多做一点工作而已，没什么大不了（Just a little extra work. It's no big deal.)

Answer

oh i see , now i understand . Thx!

Answer

then eat a little. NOT eat less. 少吃点 = 少吃一点 = eat a little   少 + verb + （一）点 means do something action a little   少吃点 少喝点 少玩点 少睡点 etc

Answer

In fact "少吃点" shall be "吃少点" in relativly formal speeching

"吃少点" = "吃(eat)" "少点(less)“

In chinese sometimes “点” is equal to "些" , and “少些” shall be translated into "less" in English

Hope my answer will be helpful =D