The best time to eat fresh foods is when it is in season.
The less time a food has to travel and or be picked to travel the more nutritious the food will be.
Example corn loses its sweetness as it spends time in transit and its sugars convert to starch.
Tomatoes get picked too early or are gassed with ethylene to help them withstand handling.
Cherries reach their max sugar level during their last few days on the tree, but are often harvested before that time because of how far they may have to travel to be sold.