Gaining

They're all the same 80% Dextrose or Maltodextrin with the remainder being whey protein. It's a total ripoff. You can go to any beer brewing store and buy massive bags of Dextrose or Maltodextrin for pennies on the dollar. That's what bodybuilders do. No need to pay $50 for that crap.

Weight gainers are designed to be a post-workout shake to put on muscle not fat. So maltodextrin is highly glycemic, far more than sugar, and signals the body to open up its cells so the protein can be quickly processed. And the carbs of maltodextrin help restore your depleted glycogen stores to aid in recovery.

If you're trying to get fat, you can find far more calorie dense shakes for cheaper. Lots of heavy cream and peanut butter based shake recipes out there. No need to pay an arm and leg for maltodextrin powder from GNC. My 2 cents.

A shake based on FAT not carbs (sugar) is going to have over double the calories.