I'm going to suggest that with FMCG providers, because their products are usually commodity items that could be purchased anywhere, that the necessity for branding is even MORE crucial. There is a business I often refer to in these kinds of discussions called "The Ginger People". Their branding story is a case study in doing it right. They used to be a little twitter entity. Not anymore.
If I am a corner-grocer, there is little to be gained by these price-wars that are so common in newspapers, etc. What is needed is a value-add proposition that makes one entity stand above the rest. A niche, be it Customer Service, Convenience, whatever. Just positive differentiation. Ads dont do that. Ads annoy, unless you're shopping.
That corner grocer, needs to spend time learning why the people in his neighborhood are shopping across town, rather than stop at his location, regardless of his prices. He needs to know what will bring them into his store, be it a particular item, a particular brand of item. One store near me lost all of my business after they stopped carrying a particular brand of Salsa. It can be that particular.
I would right now, in a fmcg, find out exactly what is bringing in my current customers and make a determination of whether they are the ones I want. If so, do the same better. If not, change it up, after an identification of who my target customer is, what they want, when they want it, etc.
Only when I know that customer like the back of my hand, do I begin advertising what my customer wants.