Good call. I notice the same thing with domesticated animals (house pets). You could feed them 3x a day everyday.

Let's look at humans for a bit. If you had to eat a sh*tload of food to tide you buy for the next 3 days, how much would you really eat? I presume you'd have about 4 servings (average food sevings) and be really full after that. I'm sure that wouldn't hold you for 3 days, right?