It sounds like you might be affected by a side effect of the statins, which is muscle weakness.  I had to stop taking statins for the same reason; I also tried Zetia, which did the same thing to me.  Since I can't take statins, I'm not on any diet per se, but I've been watching what I eat and eating smaller portions...using a smaller dinner plate has helped enormously.  I also try to get on my treadmill a minimum of 3 times a week for a half hour each time.  I still don't walk too fast, but at least I'm moving.  I've added more fiber to my diet, eating Fiber One cereals and at lunch eating vanilla Activia yogurt mixed with 2 large tablespoons of canned chunky apricots--a favorite--and a half cup of Fiber One bran all mixed together...I feel like I'm eating a dessert at lunch and a side benefit of that is no constipation, so it's a win-win for me.  I also take 500 mg of Niacin twice a day...since using these methods, my cholesterol is now under control without taking any muscle-weakening statins.   If you try these things, I hope they work for you too.