Macronutrients are a lot like hunger, however it is divided into three groups, carbs, fats, and protein. Fats and protein decrease at roughly the same speed, however. They decrease the slowest, roughly 100 minutes until you are out. Carbs decrease faster, roughly 75 minutes until you are out.
Macronutrients (and hydration) no longer affects your max health. each used to give 25% of max health hence all of them gave 100% max health. However Now only if you run out of hydration you will slowly lose health and die (you reach 0 HP).
The lesser your current macronutrients, the faster stamina depletion.
The list of effects is here