Think about this the next time you're about to order six things for yourself at Taco Bell. Delish  says it's four ways fast food joints trick us into eating more . . .

Decision anchoring.  The first option we see tends to stick in our mind, and there's a good chance we'll order it.  That's why they put big signs on the windows and near the entrance to push their new items.  It makes you more likely to order what you usually get and the new stuff they're pushing.

Price anchoring.  They make sure there's expensive stuff on the menu, so everything else does not seem expensive.  It's also why most places have scaled back their dollar menus.  Basically, the best way to sell a $2 burger is to put it right next to a $5 burger.

Playing up the "health halo."  They know we feel guilty for eating fast food.  So on the menu, they play up the healthier ingredients, like making sure you can see the lettuce and tomatoes on a sandwich.  Then we don't feel as guilty and order more.

Less face-to-face interaction.  More places are adding self-service kiosks, and it's not just to speed things up.  With kiosks, we feel like we can take our time, and there's not someone there judging us for how much food we're ordering.  So we're more likely to tack stuff on, like a milkshake or chicken nuggets.