I very much dislike Panda Express, it's just American themed Chinese food. I find their food generally bland and a little overpriced. But a lot of people love it, so I guess they're doing something right.

Mexican food is also generally pretty good for portion sizes. Find a smaller establishment and get a burrito, and you'll probably have leftovers. Don't go somewhere like Costa Vida (they're fine, but kind of bland), find a mom&pop that's well lit and it'll probably be pretty American friendly while being decently good. The non-well lit places are my favorite because they're often more authentic (instead of having to ask for lengua or cabesa, it's right on the menu) and usually have soccer games playing, but the counter staff's English may be a bit more rough. Look for a well-stocked salsa bar and jugs of differently colored liquid on the counter and you'll know you've found the right place.