It's not recommended to cook over a gas fire pit because the food drippings will clog the burner and give your food a dirty appearance. Another reason this isn't recommended is that a gas fire pit produces a yellow flame, which produces a lot of smoke. The last reason is that gas fire pits don't get hot enough to roast marshmallows properly. If you're determined to roast marshmallows over a gas fire pit, clean the burner regularly and keep a close eye on the flames. For a better experience, we recommend using a charcoal fire pit.