In keeping with this week's food theme...
I've heard some people say "I don't read fiction". That's fine. Some people just aren't that into it. But when the person making that statement is also someone who writes fiction, there's a problem. It's the same with people who want to write non-fiction, but haven't a clue because they don't read it.
You are what you eat, people.
Would you really want to buy a steak made by a vegan chef? Or a vegan dish whipped together by a professed meat lover? If you watched Top Chef Masters, you'll understand that last one. An excellent chef, and seemingly wonderful person, got kicked off the show because the challenge was to create a vegan dish, and he just couldn't do it. I felt really bad for the guy, because the food he cooked previously looked too yummy for words. The vegan dish? Ugh. I can't really imagine eating vegan anyway, but the guy's rice ice cream just looked gross. (And a slap in the face to ice cream lovers everywhere, IMO.)
The problem was, this guy didn't eat vegan, he didn't cook vegan, and I suspect his views on vegan cooking were about the same as mine. (Eww, yuck.) So, even though he's one of the best chefs in the world, he failed.
No matter how awesome a writer you are, if you're writing something you have no interest in reading, your work is going to come out the same way. And really, unless you're trapped into it like that poor chef, why would you want to?
You know how they say 'write what you know'? Well, I suspect part of that maxim is writing what you understand as a reader. If you're the kind of person who devours romance novels, one would think you'd be writing them. Or if you're strictly a non-fiction reader, take a stab at writing that. Do not write what you hate simply because it's what's you think might sell.
On the same track, let's say you love chicken, and you want to eat chicken every day for every meal. Everything chicken you cook turns out perfect, and everyone who eats it raves about your culinary artistry with the amazing poultry. For you, chicken may be enough, but I'm guessing after a while your tastes will change. And if you're cooking the same chicken the same way, your diners are going to get bored with it.
That's why I advocate reading widely. If you're only writing romance, take a dip reading a mystery novel or two. If you only write mystery, try science fiction. As with the perfect chicken chef, you may find new ingredients making their way into your dishes, and the whole experience will be better for it. Your novels will be richer, and your readers will thank you for it.
Because really, you're not only what you eat. You are what you read. The more different types of things you read, the better your writing will be. Make a glorious meal out of every story, and your readers will always come back for more.