Breakfast: Even though Burger King and McDonald's had french toast sticks and oatmeal, the only place to get a breakfast that didn't taste like pure sugar was Chick-fil-A. It wasn't super satisfying, but it was enough to get me through the morning.
Lunch and Dinner: Taco Bell and White Castle are by far the most accommodating. Most meals at Taco Bell can be made vegan by removing the sour cream and cheese and replacing meat with potatoes. White Castle also has a few vegan sliders on the menu, but unfortunately, these two chains were pretty far out of my way. Chick-fil-A had good salad options, but there was nothing with protein on the vegan menu, which became a huge problem.
Most fast-food chains lack a hearty vegan option on the menu. Sure, I could fill up on fries all day, but it proved impossible for me to actually sustain a diet of just vegan fast food because of how limited the choices were — and how severely those choices lacked any nutritional value.