I've looked through here but couldn't find this.

I remember from my classes from before that a 3 oz portion of meat is the size of a deck of cards

A medium potato is the size of your computer mouse

Your fist is the size of one cup

The one I'm stuck on is cheese - something about a 5 v battery being ???? ozs???? - I think 1 oz is the size of your thumb but I just can't remember

Can anyone help me on this?

Never Mind - I found it in the bottom of a sticky above - Eating out Sticky

One Thumb is 1 oz cheese

I am having trouble with portions also. I am thinking of buying a small scale.

I have a small scale but it's a pain as you don't have it with you at all times

Rosegarden, Once you start measuring everything at home you can figure your own ideas on how big something is for a portion.