The best kind of food I am able to think of are the foods you can get during the harvest festival. They are
Harvest Boar,
Harvest Bread,
Harvest Fish and
Harvest Fruit. You can get 20 of each every year so a total of 80 a year. If you use them completely that's 50% of your max HP.
Then you have
Bobbing Apple (unique: 5 only available during Halloween) and
Noblegarden Chocolare (duration: 7days) but these overrides your rumsey Rum when you eat it and gives you 48% of you max health.
Calculations:
Normal food is 552hp over 24sec= 23hp/s
So for the special food to be better 2% of your health needs to be more than 23hp. So 23hp=2% 23/2*100%=1150hp. So the hp of your 19 twink is more that 1150 you will get a benefit from using the harvest food of the apple/chocolate.
For my own twink with 1421hp (only including rum and no other buffs) he will get 1421/100*2=28.42hp/s from the special food. For the harvest food over 25sec that's 710.5hp (lets round that down to 710). That's 158hp more that I get with normale food.
Ofcourse we all know we aren't eating that often.
I myself only using it when carrying the flag. And I get attack use a bandage and kill the attacks. So I got the bandage debuff and not a full hp. And ofcourse no healer in range at the moment only then will you find me using food.
New discovery for me
While looking for different kinds of food I found one that is new to me namely
Green Tea Leaf. They only drop from
Riverpaw Herbalist in Westfall. At first they seem to suck at 30health and 60mana over 10sec. But if you look better you can see that the 30health is instant. And it does not share a cd with pots so even if it is only a very low amount that 30Hp might just save your life.