Every plan is different, so I'd suggest calling your doctor and/or nutritionist to discuss what you can do. I definitely have problems with pills--vitamins or medications--when I don't have food in my stomach first.
My pre-op plan was very different: protein shakes for breakfast and lunch, lean dinner with protein and veggies, one fruit per day. It was, in my opinion, much better than a liquid-only diet pre-op (although the last day was clear liquids only).
But, again, check with your nutritionist. You may be able to do something different than you are doing now. Good luck.