I know that Atkins says for induction and OWL saturated fats aren't a worry, they just should be watched when on premaintanance and maintanance. What about mono and poly? Are both monosaturated and polysaturated fats the healthy kind, or is one of them not so great?

Based on a quick review of the breakdowns in Fitday the "healthy" fats (nuts, olive oil, fish, avocado) all seem to be significantly higher in mono then poly.
*added* The exception seems to be seeds, which swing the other way...go figure!

I don't think Atkins comments on it anywhere in his book.

Anyone else know?

Saturated fats are the bad fats. This is the stuff that everyone says causes high LDL levels. When reading labels you should be looking for foods with 20% or less of the total fat being the saturated variety. Lots of LC food is 40-60% so you really have to watch the labels.

Polyunsaturated and mono-unsaturated (why there is a hyphen in mono and not in poly I don't know!) both are better for you than saturated but tend to be higher in calories. It is even thought that too much poly can increase risks for some types of cancer. Of course saturated fat is one of the biggest contributors to heart disease.

OG

I found this material on Ask.com