How to gain weight with whey protein?

Yes, all protein: Whey is a milk based protein that can contribute to weight gain like other proteins: beef, fish, poultry, eggs, etc. To gain weight you need to consume more calories than you burn. Go online to figure out how many calories you need to maintain weight, then eat more, taking into account how much you burn. You can drink whey, but it is no better than your own cheaper shake of ice cream, milk and PB!