More than halfway through my sixth decade, I have learned to live with the routine insults and occasional horrors of passing time—the daily aches and pains, the eroding senses (say again?), the too-frequent diagnosis of cancer and other life-threatening illnesses among my peers. I accept these blows, big and small, as the price to be paid for the joys I've known and whatever wisdom I've been able to acquire over the years. I accept them because, well, I really don't have a choice. There is one thing, however I will not abide: getting fat.

It would be simple enough to let it all go. As millions of middle-aged Americans have discovered, it's a hell of a lot easier to grow a belly than to not grow one. But I don't want to be one of those guys in the XXL golf shirts who look like they are about to give birth to a basketball. And I don't want to increase my risk of diabetes, heart disease and other health problems associated with obesity. Which is why, in early January, as my holiday food intake helped push my weight past the 210 mark for the first time (I'm six feet tall) I became a vegan. Much to my surprise, more than two months later I am still a vegan. I am also 12 pounds lighter and I have substantially more energy than I did when I was a flesh eater. (That's the term I use now to describe people who eat meat; annoying non-vegans, I have found, is one of the best things about being a vegan.)

I began by following the 28-day program described by the vegan firefighter Rip Esselstyn in his new book "The Engine 2 Diet." (I first heard about Esselstyn from a journalist friend who helped him write the book.) At age 46, Esselstyn, a former professional triathlete, has been eating a plant-based diet for more than 20 years. While he's clearly a hard-core vegan—"Cheese is, simply put, a disease-promoting, nutritionally vacant, calorie-dense food"—Esselstyn is no tyrant. In the book, he even offers tips about the healthiest ways to stray from the E2 diet.

I have strayed a bit myself—I don't believe it's possible or even proper to eat a baked potato without at least a dab of butter—but I'd estimate my adherence to Esselstyn's program at about 95 percent. (I was in France for two weeks last month and consumed not une molecule de fromage.) As it turned out, radically revamping my eating habits was not as hard as I expected it to be. No bacon, no eggs, no Parmesan, no steak, no problem. My success so far is due in part, I think, to my personal food history. I grew up in a big family (six kids) and while the food was always tasty, meals were practical affairs. We didn't sit around savoring our chicken à la king or our chili con carne (my mother was a wizard with her electric frying pan). We ate, we cleaned the kitchen, and later on we ate again. To me, food is fuel. Yeah, I like meatloaf and fried chicken, but lentil soup and whole grain bread fill me up just as well. Truth is, I'd be fine with it if humans, like boa constrictors, only had to eat once a week or so.

In fact, the toughest thing about being a vegan so far, aside from eating PBJs, a top vegan lunch option, which I swore off 40 years ago after eating about 2 million of them as a kid, is having to think about food so much. In some ways, I'm no different than a glutton or (God help me) a gourmet. I'm following this incredibly healthy diet, but I'm paying way too much attention to what I eat. It's sort of a pain in the ass. And kind of boring, too.

How easy it would be to go out for a couple of slices of pizza right now. Only I feel so much healthier today than I did just a few weeks ago. I haven't had my cholesterol checked since the fall (it was 209), but I'm confident that it has dropped significantly because, as Esselstyn's book amply documents, that's what happens when you become a plant eater. So I'm sticking with the program. I'll skip the pizza and have a big salad or one of those damn PBJs for lunch instead. And tonight I'll have some roasted vegetables and maybe a beer (a plant-based beverage, thank you very much). And tomorrow I'll be older, but I still won't be fat.

© 2009