It does improve their health... but the health bar doesn't move in 1-point-of-food increments... the logfile shows the increase, but the health bar moves in I think 5 point-increments. Seems every two bites is a point, so if you do 8 feedings one after the other, you should see an increase in health on the bar... and that wouldn't happen that quickly normally (less feedings depending on how many health points they're at at the time.