Buying more of a food item seems to reset its bonus from Improve Food, and I'm guessing it resets cost reduction as well. Clicking the UFO also seems to have stopped working at some point after boosting food spawn and click power. Seems like a fun game but these interaction bugs are making the progress bars much less useful than they should be.
EDIT: I might be wrong on the clicking and the boost is just not very clear at fast spawn speeds.