That was pretty much my feeling. I mean, there were issues about the Adipose, but they were a lot more complex than "look! evil alien! I will thwart your heinous plans!" and I'm not convinced a throw away remark about how it could have worked as a diet plan and a "You've changed" from Donna really washes as an acknowledgment that the Doctor's actions were morally rather murky. But I did wonder if I missed some initial set-up where it was revealed that the dieters eventually wasted away or something.