There are lots of these and the LA times has gone through and reviewed the science behind them. It’s pretty fascinating.
So, in summary
If you’re feeling cranky, drink water.
What you eat for lunch causes that 3 o’clock slump.
Omega 3 fatty acids found in fish help depression.
Turkey makes you sleepy
Chocolate brings good feelings.
Sugar takes the edge off pain.
Carbohydrate snacks make you feel calmer and happier.
Coffee improves energy and mental performance.
Sugar makes kids hyperactive.