I do moderate targeted cardio of a HIIT type routine, rarely more than 30 minutes (although I used to do more). I usually do elliptical because it doesn't hurt my feet or knees, but within the 30 minutes I do a high intensity segment (30 seconds of all-out right now, although occasionally I do one-minute segments) every minute and a half. I love cardio for the cardiovascular/endurance benefits—I have much better energy for skiing when I'm doing cardio a few times a week. So that's why I do cardio, although I've lately come to believe that perhaps it isn't the magic key to more weight loss. I truly don't know if it helps (much) or not.

Then I spend most of my time in the gym lifting weights (from 30 to 50 minutes, usually 3x per week), and I love the benefits of that too. If I had a choice to do only one, I'd choose the weights. As we get older we lose muscle, that slows our metabolism, we look flabby, weight piles on easier due to decreased metabolism due to loss of muscle, all that. I love having strong muscles.

I WILL say this: I am certain FOR ME that I lose better when I'm doing at least three gym sessions per week. I don't think I need to do more, but when I get lazy and don't go to the gym at all for awhile, I absolutely do not lose weight as easily, and I tend to hang at a weight for ages even if all my eating is spot on.

On top of everything else, working out with weights feels so fantastic mentally, that alone makes it worth it.