Slim Fast (Slimfast) is the most common diet shake and meal replacement. The Slim Fast Plan calls for a shake at breakfast and lunch, and then a sensible dinner. You are also allowed two additional pieces of fruit and a Slim Fast nutrition bar as needed during the day. The sensible dinner may be used for any meal, as long as the two other meals are the diet shakes. Any diet that is lower in calories than your body needs to maintain its current weight should promote weight loss. The Slim Fast plan averages about 1,200 calories a day, which will cause weight loss for most people, as it is at least...