Guild Wars 2

I noticed this last night during play (before last nights patch) where I had metabolic primer active, but no nourishment with it.

I used a plate of steak (100 power, 70 vit) and got 1 hours duration off it even though I had 8 hours on the primer.

I logged in today, used an omnom bar and still, I got 30 mins nourishment even though the primer has over 6 hours left on it.

I’m not sure about the first instance of using food (in your case), but the Metabolic Primer only works for one food item. If you use another food item, the Primer will have no effect on it.

“Metabolic Primer(12 h): Any food eaten while the primer is active will have the same remaining time as the primer, rounded up to the next hour. The metabolic primer does not stack.”

Any food I eat does not get the remaining metabolic primer time.

I’ve used them before and been able to change foods midway through.

You must be one of the lucky ones.

Nope, just had it happen with another one, whatever new food you eat should have whatever duration is left, as stated here by developer Curtis Johnson: http://www.guildwars2guru.com/arenanet-tracker/topic/290462-metabolic-primer-what-is-the-effect/

“you can eat food during the 12 hours.. it will change which food buff you have but the duration should still last the rest of the 12 hours (rounded up, so never less than an hour)”