Most people know that caffeine in coffee will wake them up, and citrus fruits offer Vitamin C to boost the immune system.
Beyond these basics, though, lots of other foods can benefit you in various situations -- like when you're stressed out or need to focus.
For instance, are you having trouble sleeping? Have a handful a cherries -- they're the only food in nature that has melatonin, a powerful hormone that promotes sleep.
Foods you should eat when ...