One thing that struck me was the fact that if they were all morbidly obese, then they most likely had obstructive sleep apnea. However, I don't recall seeing any CPAP masks or machines in the movie.

If you also recall some of the older sci-fi movies, notice how all the aliens have huge brains and very tiny faces. If you think about what's happening to our jaws (getting smaller) and our brains (getting larger), it's conceivable that in a few million years, we'll all begin to look like aliens. By then vocal communication will be gone, since complex vocal speech is detrimental to breathing and swallowing. We'll have evolved to the point of communicating only through mental telepathy, and everyone will be hooked up to positive airway pressure machines while sleeping at night. By then they may have the technology to turn on a switch that bypasses the upper airways directly at night to function like a tracheotomy, except that no surgery is needed. Will they have developed a way to function without sleep?

Pure speculation, but not too far fetched. What do you think?