Food can be found in three ways:
1) Extra cases through Teddy, which restores all stamina.
2) Found throughout the game.
3) Food that can be bought from Amanda's shop. The game won't let you buy a healing item if you don't need it.
First, there are five bits of food that are not obtained through Amanda or Teddy. In the apartment, next to the fortune cookies is a mug of
coffee. Between the coffee machine and microwave on the counter is a blender. Use this to get
Vegetable Juice.
In Episode 2, before you enter the cargo container, there are three to be found. From the starting position, move all the way forward until the way is blocked by suitcases. The one directly in front of you belongs to an NPC, and the one on the right has Deborah Anderson's name on it. Open both suitcases; the one in front of you has
Expensive tequila inside, while Deborah's has
White House Chocolates. Finally, just before entering the cargo container with Olivia, turn left at the phone to find a box on the right. Open this up to find
A dozen water bottles.
Second, complete all of Teddy's extra cases. There's one in the prologue, two in Episode 1, and three in Episode 2. Completing all these will earn you an achievement as well as the following items:
Clam Chowder
Fish and Chips
Hot Dog
Lobster Boil
Pizza
Steak
T-Bone Steak
Finally, the remaining 42 items are all found in Amanda's shops. Conveniently, her shops carries all remaining items in Episode 2. However, there are two caveats: her inventory changes whether you're in the apartment or the past, and the game will not let you buy a healing items that you have no need for.
Therefore, what you want to do is do something that will consume a bit of stamina, then go to Amanda's shop, buy the next food on the list, repeat. For the apartment, I suggest doing this at the same time as getting all the fortunes. I did it in Episode 2, when the shop had the most food listed. For food in the dive shops, go after the extra cases or interact with things that you don't necessarily need to.