Now in my game I have a medkit that heals for 40 at the moment but this is because I could not figure out the system I wanted.

I want it so when I pickup food it is automatically used and gets added to a counter of how much food you currently have. This would heal you for one health every 2seconds and when you have full health it would do nothing until health is lost. I assume this would be a combination of triggers and data editor but I am lost when it comes to triggers.

Let me think out loud here.

Var [food] initially=0

Trigger: Player Takes Damage

If Player Hp is less than 100%
If Var [food] >0

Then

Var [food] -1
Add unit health 1
Wait 2
Repeat trigger

.. hmmm, this is just thinkin' out loud, might work if set up propperly.

You could probably do this with data editor alone. Using a behaviour that uses up charges and gives health only when a unit is under 100% health should be do able.

You could set it up so that your food items add charges and have a periodic behaviour which causes a modify unit or healer effect with a cost of charges. You would also need a validator on the behaviour which checks to make sure the unit is <100% health

"durr" activates on kill of Zergling (assuming you kill your powerup to acquire it or something), and player 1 is the killer. P1 is given 40 "food (minerals)."
"durr2" works every 2 seconds, checking if the player has at least 1 food. If so, and the player's unit is not full HP, the player loses 1 food but the unit is healed by 1.

You'll probably be using something along the lines of that.

I tried going full data with it but I can't seem to get it to work. I got the food behavior made and added it to my unit where it shows it along with stamina and power with that the food is meant to add 2 health per 2 secs. I am trying to make it so when the health kit is used it added it to the food bar but I can't get it to add to the counter.

What are you using for a counter?

Hmm was planning on making the food behavior I made the counter but I guess that counts as an attribute and can't be a counter..hmm. Is there just a food counter already in the code somewhere.

There are a couple ways you might be able to do it. One is charges (need to be added to units through triggers), you also might be able to stack the behaviours. I would suggest charges, you can see an example of their use in the secret mission (for jim's pickups).

Unless im missing it I can only find how to take a charge away not add charges to a unit. I also am not sure how I would find the secret mission.

On this note, where is the HP regeneration of the Zerg units located?
Would there be some way to turn that on or off depending on when it's needed?
And in StarCraft 2, the Zerg 'regen' works both directions, example would be when a building is off creep, it slowly loses health instead of gaining.
Would be helpful to make some sort of 'poison' effect in given areas of the map or something, or force some sort of unit to stay on Creep.

Data editor, unit specific.
Go to units -> stats -> HP regenration

That hp losing is nothing else than an effect, having a perodic 2nd effect reducing the building's hp by X.

Anyone would be kind enough to create a Wiki about this please?
http://www.staredit.net/?p=wiki

Although strange in order to add charges simply take away a negative amount. To open a campaign map go to open a file like normal but change the tab on the top of the window to campaign.