What kind of person would The Restaurant Dieter be if he lived a life of pious eating all the time? A cranky one.

So the joys of a sweet treat now and then cannot be cast aside. That’s especially true when in New York. This is where the city magazine recently proclaimed toast as…you guessed it, the newest thing since sliced bread.

I make fun of New York’s food obsession here, but the city, one Greenwich Village Bakery and “Sex and the City” launched the cupcake craze. For that I am deeply grateful.

I’ve been on a warpath against most fine restaurants today because cake has fallen from favor as a dessert option. The menu only has one cake usually — something chocolate, flourless, intense, gushy — and then a creme brulee or flan, fruit and pasty or crunch something, ice cream and sorbet, tiramisu and maybe a cheesecake or carrot cake. A wonderful golden layer cake with fresh stawberries and whipped cream or a lovely coconut cake is passe.

So when the eyeglass shop wasn’t open yet, I made a beeline to Upper West Side outpost of The Magnolia Bakery, the Greenwich Village institution where those impossibly thin SATC girls bought their cakes.

At the counter, I spied a caramel dripped cupcake and one topped in snowy coconut. I’m partial to red velvet cupcakes, but have not forgiven Magnolia for messin’ with the classic recipe and substituting white buttercream frosting for the cream cheese icing. I’d eat your shirt if it had cream cheese icing on it.

Just for the hell of it, I asked the counter girl: “Do you have nutritional information on any of your cupcakes?” She resisted the temptation to call Bellevue and have me committed and said no.

As I sidled up to the checkout, another customer was confessing to the register clerk that she tried a brownie sample because she wouldn’t dare eat a cupcake. The box she had was for someone else?

“Oh, it’s only 10 calories,” she told the woman. And then, seeing the look on my face added, with a laugh, “give or take a hundred.”

Well for that nutritional bargain, I figured why not and took a sample myself. Self-delusion is a beautiful thing.

Coconut cupcake and brownie sample

So what was the damage? Finding good information about cupcakes is tough online. A lot of websites will rely on the nutritional labels on a pre-packaged food, such as a Hostess cupcake. But that too is a wonderful exercise in self-deception, according to Dr. Charles Stuart Platkin, who writes as The Diet Detective. According to National Public Radio, Platkin recently determined that my Magnolia treat came in at about 389 calories and nearly 19 grams of fat. Another popular local chain has cupcakes with 780 calories and 36 grams of fat. But a Hostess cupcake is a more modest 181 calories and 6 grams of fat.

And that brownie sample? Weight Watchers teaches that an item the size of your thumb is about 1 ounce.

Using Platkin’s estimates and my Weight Watchers Points E-tools, I figure that cupcake cost me 7 daily points out of my 38 daily allotment. And that supposed 10 calorie brownie sample was more like 100 calories. (The sales clerk was right after all!)

I could have mitigated the damage. Today’s cupcakes have snowy peaks of frosting that make Everest look small, compared to that perfectly acceptable smear mom used. If a teaspoon of buttercream frosting is about 44 calories and 1 gram of fat, I could have easily scraped a couple of tablespoons off and still enjoyed it.

But I didn’t. I ate the cupcake in four bites, my nose earning a requisite dollop of frosting.

So lunch is another turkey sandwich for me.