This is actually a vegan/macrobiotic restaurant. Have visited several times during the last couple of years, and everything was always vegan. I explicitly asked the cook/waitress again when I last visited (Jan 2014) and she confirmed.
It's only open for lunch on weekdays and there's only one plat du jour (typical macrobiotic style with a collection of several different items on your plate, mostly organic). Nice, but no culinary gourmet experience.
For a more detailled review and photos, see our blog about De Graankorrel in Ostend:
Cons: only open for lunch on weekdays, only one plat du jour, sometimes slow service