Meg, from what I've learned it seems to be the change in macronutrient ratios that makes the biggest imapct.

Going from 60% fat to 30% is a big change. Going from 10% carbs to 30% or 40% is also a big change; same for protein. Looks like you're doing more of a modified Zone, and this is where my breakdown seems to happen most naturally.

Cutting down to 20% might make a difference; it might not. The only way to find out is experimentation Personally, 20% is tough for me, but then again so is doing 40% carbs!

Nat