So I’m sitting in the hairdresser’s chair a couple of weeks ago when a copy of Star magazine grabs my eye. I’m not going to lie to you: I never read this kind of stuff. I’m not kidding. It’s not like I’m reading Dostoyevsky instead, it’s just that I’m really not that interested in what Jennifer Aniston eats for between-meal snacks.

But this copy, dated for Jan. 5, 2009, was impossible to pass up: The cover was strewn with glamour don’t shots of “stars” in all their beach-exposed bareness. (I use the term “star” loosely, since in my mind Ava Gardner and Sophia Loren were “stars.” Lindsay Lohan is not.) “All new photos” of Brooke Mueller (who is that?) and yes — Jennifer Aniston — in their near-birthday suits. And, of course, the gratuitous shots of those, well, not so beautiful: Rosie O’Donnell’s thigh bulges; Star Jones’ plastic surgery scars.

It seems that January not only rings in a new year of pressure to get on that diet and exercise, it also gives us permission to make fun of famous people who don’t. And envy the ones who do. We live as vicariously as ever through them.

Honestly, I’m not sure why we do this to ourselves every year. Isn’t it enough to be late with bill payments and feel guilty about not calling our mothers more often?

And January is the worst time of the year to diet. Our natural tendency in winter, as former hunter-gatherers, is to hole up in a cave and pack on some fat. Forty thousand years of evolution apparently have done little to change our inner workings. Why the heck else do you think you’re still craving that caramel latte, even after having so many on those long shopping sprees during the holidays? After all this time, there’s still only one formula for losing weight: calories in, calories out.

Yet we pat ourselves on the back and read up in Self magazine about all the so-called super foods, like eggs, lean steak, chiles, blueberries and olive oil. Sure, research has given us breakthrough after breakthrough, letting us know that spreading almond butter on our whole-wheat toast will lower the glycemic index of the bread — making our blood sugar dip less (which in turn keeps cravings at bay).

And sure, diets that tout high protein and low carbs, such as the South Beach, do get results — especially in the first few weeks, when you need to see the scale dip the most. And “paleo” diets that call for high protein/low carbs, with as little processed food as possible, can help sculpt the bodies of those who are already in shape.

But the bottom line (pardon the pun) is that if you eat too much and don’t exercise enough, you’ll gain weight. It’s that simple. We can’t all be expected to never eat a bowl of white pasta again, anymore than we can be expected to look like Aniston (she has lots of help doing that, after all).

So relax. Take the dog for a walk — better yet, a jog. And make a resolution to make no more resolutions. Live life in moderation. And stop reading the tabloids.