I made a New Year’s resolution to become a vegetarian. Or a mostly vegetarian.

I’ve been thinking about it for a long time, but with young children who love meat and don’t have the broadest palates, I think it’s important to feed them protein any way I can get it in them.

Having passed 40, I’ve finally realized that I can no longer eat what I want with impunity. Further, as a doctor, I believe in practicing what I preach, and my legs could no longer straddle the gap between action and rhetoric.

That, and I hit 192 lbs. on the gym scale.

I calculated my own BMI at 26, edging toward 27. I was officially overweight, just like two-thirds of Americans.

I have a sweet tooth. I’ve been known to polish off a whole plate of cookies, a la Ziggy, just so they won’t be there tempting me.

Another rude awakening was my cholesterol. Total 254, LDL 177 (!).

I was in disbelief. When I thought about how I would treat a patient with my numbers, I’d reach right for a prescription pad and start a statin drug (like simvastatin [Zocor] or atorvastatin [Lipitor]).

But like a lot of doctors, I’ve long felt impervious to the maladies that I treat.

No more.

Over the holidays I read a New Yorker profile of John Mackey, founder & CEO of Whole Foods, in which he mentioned a book called “The Engine 2 Diet,” by a Texas firefighter and former pro triathlete named Rip Esselstyn.

Since I grew up in the same Cleveland suburb as Esselstyn’s family, I was intrigued enough to buy the book.

For the last four weeks, I changed my eating habits accordingly:

1. No meat (surprising: no fish or poultry, either. Strictly vegetarian. ”Nothing with a face or a mother.” Eggs are out, too. Esselstyn does permit tapering down the meat habit, allowing small portions of chicken or fish the first couple of weeks to acclimate. I went cold tofu, though.).

2. No dairy (even yogurt, which I frequently tout to patients as a healthy food).

3. All the fruit and vegetables I want.

4. No oils (this surprised me, given all the attention to olive oil and things like flax seed oil that are high in unsaturated fats).

5. No refined grains (whole grain is ok, high in fiber!)

6. Sweets: only acceptables are fruits (“nature’s candy”), a little bit of sorbet, and a small amount of Dark (>70% cocoa) chocolate (avoid milk!).

The book promises much to those that follow its contents: more vigor, lower weight, lower cholesterol, and by inference (and looking at the exercise photographs near the middle) greater accomplishment and happiness.

Esselstyn is bursting with optimism that his diet can prevent (and even reverse) heart disease. He bases his ideas on the work of luminaries like Dean Ornish at UCSF, who has shown in the medical literature that extremely low fat diets (less than 12% of total calories from fat) improve symptoms, longevity (reducing heart attacks) and cause coronary plaques to actually regress. Esselstyn’s own father, a longtime Cleveland Clinic surgeon, published his own similarly themed book, “Prevent and Reverse Heart Disease.”

Esselstyn says that his data shows that total and LDL cholesterol can be significantly lowered, with a weight loss in the range of ten pounds in four weeks.

Staying on the diet requires planning. I needed to change the way I shop for groceries, and scour nutrition labels more carefully than I ever used to. By planning ahead, you have a small nutritious snack (e.g. a handful of healthy nuts) at the ready so that you don’t resort to junk food or quick, easy thought-free eating.

How’d I do?

After exactly four weeks of following the Engine 2 diet (with only a bit of cheating–a splash of non-fat milk in my coffee, occasional cheese on a whole wheat sandwich, a cupcake for my sister-in-law’s birthday), I was astonished:

I’ve dropped ten pounds. I feel remarkably different: More energetic. I sleep better. I have few dips in energy throughout the day. Aside from one day each of the first two weeks (where to satisfy my sweet tooth I overindulged in peanut butter or almond butter), I find I’m no longer craving any of the junkier things that I used to. I feel much more in control of my eating–both what I eat and the quantity. I’m reminded how as a culture we habitually overeat. We could all get by on so much less.

Here’s the stunner: Remember my total cholesterol of 254, LDL 177? After four weeks, the new numbers are total cholesterol 160, LDL 103. I think I’m going to keep this up.

John Schumann is an internal medicine physician at the University of Chicago who blogs at GlassHospital.

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