To me it's very simple: you can't eat more carbs than you burn.

I used to eat low fat (25 or less a day) high carb (I estimate 300-350 a day) and worked out 45 minutes cardio on a climbing machine, plus 45 minutes floor exercises with light weights. And guess what?

I lost weight. I was 150 and a size twelve. I was happy. I thought I was healthy. I thought I'd figured it all out.

Fast forward to me in my 40's, with no time, money, or space for my old exercise routine. Yes, yes, yes....if it's "important" enough you'll do it, etc, but I was going to school full time with commuting both ways, had a part time job and a fiance. If you'd thrown a couple of kids in the mix I'd have had a breakdown.

Starting gaining weight. I hadn't changed the way I was eating, I just didn't do much exercise beyond a long walk a couple of times a week, and I was lucky to get that.

Low carbing, I lost 40 pounds in 4 months without exercise, I weigh 147, and I'm a size TEN.

Ya'll can do the math. My point is:

You can't eat more carbs than you burn.

Period. All the fussing over proportions and ratios are fun to debate, but it all comes down to that, in my personal experience.