It depends on the intensity of your workout, as well as your total calorie balance for the day. If you're not busting your butt in the gym and burning a significant amount of muscle glycogen, then the dextrose should be left in the jar. Also, adding in 75 grms of carbs (~300 cals) on top of a diet that is already too high in carbs or calories may add fat to your bod. But if you're trying to gain muscle and are working hard and are eating right through the rest of the day, then some simple post workout carbs are good.