I am thinking about buying magic food to sell, is there any one food that is more needed than the others? Which ones are you wanting to buy the most? 

-Thanks for reading!

WAID

It all depends on who you want to sell it to- I don't think any one item is more desired than others. Each of the characteristics are required for something in one form or another (quest, crafting, battling, exploring requirements).

Personally if I had the interest/time I would buy Bamboo Berries because it increases strength which increases the avaliable breedings. 

Sometimes people use magic food to make a pet that is weak in that area more rounded- and some to give the pet an advantage in an already high requirement.

At this point in the game there is not a terrible need for super high stat pets if you breed well. I think it could become more important though.

I'm just rambling now.... Sorry!

I haven't kept track, but I think I've mainly used Cactus Melons, Bamboo Berries and Nutpeas. 

And my least used would probably be Glowshroom.