To gain weight, you need to be in a calorie surplus by intaking more calories than you burn. Some take this as a free pass to eat whatever they want, whenever they want, AKA a “dirty bulk.” This typically results in large amounts of fast food, desserts, and other calorie-dense foods. While these can be useful, especially for those with a low appetite and/or high calorie expenditure, using it often and without a proper plan can be a slippery slope. 

This doesn’t mean you can’t occasionally indulge in fast food, or have a second helping of dessert. After all, you will have an increasing calorie “budget” compared to weight loss and maintenance phases. Having foods you enjoy more often, whether they’re calorie-dense or not, is a great morale booster and can keep you on track. But it’s important that you maintain overall good habits.