Sure, I add Carnation Instant Breakfast drink (the powered kind). I use one packet per cup of coffee. I always get chocolate but there is also vanilla. (Vanilla does not have as strong of a flavor as the chocolate.) With each packet you get 130 calories, 5 mg of protein and other nutrients. There are probably other powdered protein powders that you could use as well, but this one is easy to find at grocery stores, so I always get it. It was recommended by my doctor as a way to keep my weight up.