According to Google translate it is 一个面包, but that doesn't sound right.
How do I say "A loaf of bread"?
UPDATE:
This is what I mean by a "loaf" of bread. Not just a bun.
It depends a little bit on the type of bread.
For a long bread 条 is used. For a slice of bread 片 is used. 块 can also be used for a slice, but is also used for buns, a piece of bread or a complete bread.
I don't think native speakers can give you a definite answer simply because we don't eat bread that often here!
I would say something like 他吃了一整块切片面包 or 他吃了一整袋切片面包. 切片面包 is literally "sliced bread". Most of the bread you see in Chinese grocery stores (超市) is sliced.
in verbal Chinese, you can just say 一个面包,
if you say 片, 块 etc. that seems a little formal.
In verbal Chinese, people don't care which measure word to use. We just say 个 in most situation.
note that just in verbal.
我吃了俩(or 两个)面包 她刚吃了1个番薯、1个面包、5块饼干、2个糖果…这样吃一餐,会不会长胖?
一条面包is fine. same like 一条香烟 etc http://www.15buy.cc/goods.php?id=6007
The link below is 一包香烟, it is soft page cover( if it's hard page cover , it's 一盒香烟,some of the time they are interchangable) http://wenwen.soso.com/z/q139243191.htm?pid=ask.box