My surgeon has me on a calorie restricted diet of a shake at breakfast, shake at lunch with a lean slice of lunch meat and whole grain braid, 3 oz of chicken/pork/white fish with 1/2 c brown rice and 1/2 green veggie at dinner. The last day before surgery is all clear liquids. I just read about a clear liquid with protein in it that might help Cytomax Pure Protein Performance. It has 40g of protein in 20 oz. I think the weight loss is the most important thing and I don't know why some surgeons do all liquid. I would call you surgeon and ask if you can switch and tell them why.