Going from memory about 30 years ago, I heard a lecture on the history of fast food. Basically, the poor Japanese rations of WWII were nearly inedible. Their gt found that they could get soldiers to eat the bad food by adding lots of MSG... monosodium glutamate.
If memory is correct, Colonel H. Sanders learned of this and added it to his chicken batter. Sales jumped way up as this flavor enhancer also caused addiction. It affects the neurological hunger receptors and thats why an hour after you eat it, you're ready to eat again.
Story goes that he shared the secret ingredient with McDonald's owner Ray Croc.
Eventually, all fast food joints used it excessively and routinely .
