Are dry-roasted peanuts less fattening? Just look at the labels. Vendors have managed to sell the idea of dry-roasted nuts as a diet aid, but they can’t lie outright on the packages. Planter’s Cocktail Peanuts have 170 calories an ounce. Planter’s Dry-Roasted have 160 calories-scarcely enough of a difference to bother with. You do even worse with Plantar’s Salt-Free Dry-Roasted Peanuts, which contain not a calorie less per ounce (170) than the regular peanuts.