First of all, the majority of people, unless you are an ultra-endurance athlete, will be consuming sufficient protein.
Recommendations I have seen say around 0.8g per KG of bodyweight in inactive, 1.2g per KG if you are active.
This is not saying that more protein is bad, its just not as significant as people think. I would say its more significant that you are eating protein within 2hours pre workout and 1hour post workout.
In a overall view:
Protein promotes muscle regeneration and repair
Carbohydrate limits muscle breakdown and fatigue
If you are looking to bulk, you basically need to eat more. Yes this will make you heavier and fatter, thats kind of the point. You will also gain muscle too. The amount of muscle you gain depends on the amount of resistance training and how clean you eat.
If you are looking to cut, I would suggest a low carb diet for two reasons 1) Its easy to cut out the processed grains and sugars 2) It allows you to eat a good amount of protein and maintain muscle mass.
I wouldn't actually go to a protein store to ask for this advice, they will advise you to sell their products. The best is probably to look at some unbiased websites which are research based. Exrx and Bodyrecomposition are great references which you will have to Google because I can't post links yet.
I'll end with don't listen to one person or take advise from one source. Ask why they recommend that, what evidence/research do they have?