In a mixed macronutrient diet with excess calories, the body preferentially stores dietary fat over carbohydrates.

“if you have a diet that say say the American diet 50 50% carbs 35% fat and you take in um 1,000 calorie meal or 800 calorie meal which one are you going to put into fat quickest you're going to put in the easiest one the one that's already fat and so the carbohydrates going to get burned and the Fat's going to go to fat”