Slimfast is sugar laden crap. The best protein, mineral combination IMHO is 50% Met-Rx with 50% Whey protein such as Optimum Nutrition 100% Whey. Try to get in a minimum of 5 small meals a day consisting of Protein and fiberous carbs. (green veggies) Drink lots of water and exercise.
I have a blender in my office at work, thus it's easy for me to whip up a shake. You can always make them in the morning and bring them to work in a plastic thermos. Make enough in the morning for 2 servings and pack along some veggies.