When a recipe calls for half and half cream or whipping cream, does it make much difference in taste to substitute non-fat product?

In my opinion, YES. Not only does the taste change but the entire recipe and consistancy changes. Some things do NOT mix with others.
You need to use a recipe for non-fat if that's what you want.:)

I have tried using 2% milk instead of whole milk and it just wasn't the same and sometimes even curdeled.:eek:

Non fat receipes are abundant, you only need to Google AND they taste great.:D

Yeah it would be a thinner consistency and not as rich.

The way I figure it if I am going to eat sweets I WANT it to be all out with the rich taste of the heavy creams and all -but that's me -no wonder I avoid desserts.