By Abrahm Lustgarten

It was a cool morning, like most in San Francisco, and as I clicked into a low gear and stood up to pedal the last steep yards of a hill, I gratefully gulped the moist air. I’d been pushing hard lately, running in the evenings and cycling each morning in anticipation of a grueling adventure race season just a few weeks away. I thought I was pretty well prepared: I’d fueled my body with a rich, mostly vegetarian diet—lots of pasta, some fish, and a handful of vitamins each morning—and dutifully mixed in rest days with workouts. But on this morning none of that seemed to matter. My quads ached and throbbed with every revolution of the pedals. And though I wasn’t breathing hard, I felt the strength in my body slipping away. Finally, I had to stop. I was, quite simply, out of gas.

In the weeks afterward I experienced more of what I started calling “exercise hangovers”: No matter how much rest I took in between workouts, a long day on the trail left me exhausted for two full days afterward. Finally, I checked in with a doctor, who couldn’t find anything wrong. After another quizzical look, this time from an athletic trainer, I started wondering if I was eating right—and for the first time, it occurred to me that I could count on one hand the number of vegetarian athletes I knew. Most of my friends regularly scarfed meatballs and skirt steaks to replenish the gaping caloric hole left by a day of exercise. Was it possible my diet was holding me back?

In a word, yes. It’s not that vegetarianism per se was the problem. The lion’s share of studies on its health benefits are overwhelmingly positive. The American Heart Association and the American Cancer Society, for instance, both endorse it, crediting low amounts of saturated fat for decreasing levels of bad cholesterol, diabetes, heart disease, hypertension, and even prostate and colon cancer. But the fact is that finding the right balance of nutrients is a lot harder when you take out the meat. “You really need to know what you’re doing,” says Melina Jampolis, who specializes in nutrition and weight loss at San Francisco’s Saint Francis Memorial Hospital, “and I’m just not sure many vegetarians really understand how to eat a truly balanced diet.”

She told me that vegetarian diets typically lack iron, omega-3 fatty acids, and a host of other nutrients from B-12 to zinc. Creatine, a nutrient associated with muscle strength, can only be found in fish and meat. And in the case of vegans, vegetarians who abstain from all animal products, including milk and eggs, the consequences can be even more dire: Many are actually malnourished, says Elson Haas, a physician and founder of the Preventive Medical Center of Marin in San Rafael, California. In short, simply cutting out animal products doesn’t necessarily mean you’re doing your body a favor.

That news would certainly have come as a shock to my parents, who decided to become vegetarians in the 1970s for health reasons, and because they didn’t believe in killing animals. My mother was a model vegetarian, going to great lengths to balance our diet with tofu, legumes, and nuts. For the most part I went along, hoping kids in the school cafeteria would mistake my fake soy hot dogs for the real thing. It wasn’t that I eagerly swallowed whole bunches of lettuce, but when I found myself in McDonalds, I ordered the fish fillet or fries (the closest thing to vegetarian fast food back then). Mom also did her best to keep it interesting for us kids, livening up the table with her famous nut and grain-based “meat” loaf, which we slathered with ketchup.

I didn’t particularly share my mother’s enthusiasm (or her idea of a tasty meat loaf), but I stayed a vegetarian, mostly out of habit. By my twenties, my heart ticked like a freight train, my body was trim and strong, and I gave credit where I thought it was due—to a plant-based diet that was low in fat. Not until the onset of that relentless fatigue did I start to consider what I might be missing.

Like protein, for starters. “If you’re not getting enough protein you’re going to be tired,” says Molly Kimball, a registered dietitian at the Ochsner Clinic’s Elmwood Fitness Center in New Orleans. “You won’t have what you need to sustain energy, alertness, muscle repair, and muscle maintenance.”

And here’s the rub—it’s not just protein you need, but the right kind of protein. Wheat-based protein, for instance, is only half as available to the body as animal protein, according to the American Dietetic Association, and leaves out many essential amino acids. Isolated soy, like the kind in veggie “chicken” and other fake meats, can provide most of these missing amino acids, but not in the same highly usable form as those found in meat.

Eating a vegetarian diet can also lead to vitamin and mineral deficiencies, resulting in a greater vulnerability to colds and other illnesses. While Haas gives a big nod to the health benefits of a plant-based diet, he says that any time you choose to limit options, there’s potential for coming up short. “I see a lot of vegetarians who are depleted,” Haas says. “Their immune systems don’t function quite as well, and they may get sick more often.”

Take zinc, a powerful antioxidant. It’s much more easily gleaned from lean meats like chicken and turkey. And there’s no plant-based source at all for B-12, deficiencies of which can impair cognitive development, among other problems. (Vegetarians might not even know they’re deficient in this vitamin because high levels of folate from green vegetables tend to mask the shortfall in blood test readings.)

Also, the type of iron offered by plant foods can clash with a plant-based chemical called phytate, which blocks iron absorption and in the worst cases can lead to deficiency and anemia.

There’s another potential hazard for vegetarians: In place of meat, many people end up eating a lot of potatoes, bread, refined-flour pasta, and white rice, says Kathleen Wilson, a physician at the Ochsner Clinic and author of three books on nutrition and health. These high-glycemic foods aren’t very nutritious and act like sugar in the bloodstream. In benign cases this leads to energy swings; at worst, these sugar spikes stimulate insulin production—and a passel of health complications.

“The higher the insulin levels, the more likely a person is to be fat and have low levels of protective cholesterol, and to develop diabetes and premature heart disease,” says Wilson. While she once thought a meat-free diet was the healthiest kind simply because it was low in fat, “I have since come to think differently,” she says.

So what’s a well-meaning vegetarian to do? The key to enjoying the benefits of a meat-free diet isn’t all that mysterious: You’ve just got to make sure it’s the kind that also emphasizes vitamin-rich plants, grains, and fruits with higher than average shares of cancer-fighting antioxidants like vitamins C and E, along with fiber, minerals, and phytochemicals.

Simply eating a mix of meat, junk food, and an occasional salad, the typical American diet, won’t do it—but you won’t get crucial nutrients through lackadaisical vegetarianism either. Even I, who dutifully spurned sugary, highly refined foods and did my best to include tofu, couscous, and brown rice on my plate, was probably both iron and protein deficient. At least that’s what I concluded after I was forced to stop dead several times on hills.

I’m now trying to be even more conscientious about what I eat. I pair certain foods for maximum return—eating an iron-rich plant food, like broccoli, for instance, along with vitamin-C-laden foods, like tomatoes, blocks the phytate and can get you the dose of iron your body needs. I also load up on nutrient-boosted foods, from fortified whole-grain bread, with 5 grams of protein per slice, to orange juice with calcium. And I take a good multivitamin and an omega-3 fatty acid supplement. But I’ve learned the sad bottom line for vegetarians: There aren’t many shortcuts to eating well. Being a responsible vegetarian takes work, and I’ve decided I don’t want to work that hard.

So I’ve started to bend the rules a bit. In the weeks following my alarming episodes of fatigue I made an effort to eat fewer noodles and more meat and fish, which naturally provide useful nutrients, usually in the precise way you need them.

The variety was actually exciting for this longtime plant eater, and with a fish market around the corner, meals were both cheap and fresh. Within a week or so I’d perfected salmon teriyaki and added grilled shrimp to my tiny repertoire of fleshy foods. The white meat of chicken seemed benign enough and so I eased into eating that as well. But a few bites of steak made it clear where to draw the line; I didn’t particularly like the taste, but I really couldn’t stomach how fleshy it was. Still, all in all, it wasn’t too hard to soften my childhood habits, especially since they weren’t based on any moral reasoning.

It’s possible I’d never have run into any serious health problems had I not been running 40 miles a week. But it’s also possible my casual eating style would have caught up with me anyhow; I was bound to gain weight with a diet so heavy in carbs as soon as I stopped training, and a lack of B-12 has been linked to depression and memory failure.

I’m not the only one in our family who’s made changes; my mother recently relaxed her vegetarian rulebook too, not because I told her to but because her doctor suggested that doing so would help her keep up her strength. Now she eats fish and dairy foods, along with her leafy greens and stir-fried tofu, and admits she has more energy than she used to.

As for me, I can see now that there is no way I would have gotten through my first race season without adjusting the fuel I put into my furnace. I didn’t win, but after the equivalent of back-to-back marathons plus a 100-mile bike ride, I was happy to finish. After the switch to eating meat—about four days a week including the fish—I felt a steady strength and endurance I hadn’t known before.

I’m still training and still tinkering with my diet, but I’ll never go back to a meat-free regimen. I’d like to be that 50-year-old pounding down the trail; that 60-year-old gracefully carving backcountry ski turns; that 70-year-old who finishes a marathon. Based on my experience so far, I’ll need a high-octane, protein-rich, and yes, meaty diet to do it.

How to Be a Good Vegetarian

I was a vegetarian with the best of intentions. I skipped junk food and concentrated on meals I knew were rich in vitamins and minerals, but I learned—the hard way—that that wasn’t enough. If you take on a meat-free or meat-light diet, here are the core trouble spots to look out for and solutions to help maximize the nutritional value of what you eat. • Mistake: Falling short on iron. A deficiency of this mineral, especially for women, is one of the greatest pitfalls of a vegetarian diet and can lead to anemia in the worst cases. And while you might think you’re eating plenty of tofu or spinach, the iron found in plant food is more sensitive to substances that block absorption, like phytate, caffeine, and fiber, so your body might actually be rejecting the iron in the foods you eat.

• How to fix it: The American Dietetic Association recommends vegetarians eat nearly twice the recommended daily allowance (RDA) to compensate for absorption issues. Try eating “inhibitors” separately (downing coffee after a meal is not great timing) and enhance iron absorption by pairing iron-rich foods like soy and green vegetables with acidic complements like citrus and tomato. Pumpkin and squash seeds, lentils, and fortified cereals, like cream of wheat, are all high in iron. As with any nutrient you can get from supplements, it’s better to get it from real foods if you can. Visit eatright.org for details on nutrient components of your favorite foods.

• Mistake: Not getting enough or the right kind of protein. Proteins should make up about 15 to 20 percent of your diet, but just as important is getting the right type. Animal-based proteins contain a more complete suite of amino acids and omega-3 fatty acids—nutrients that aid in everything from sleep to calcium absorption.

• How to fix it: There are plenty of good non-meat protein sources. Isolated soys, like the kind found in “veggie” meats and phony bologna, which are often fortified with B-12, can provide a fully balanced protein intake. And eggs are among the best sources of protein anywhere. Saint Francis’s Melina Jampolis says that by ensuring that roughly half of your six ounces of daily protein comes from animal sources (milk, yogurt, and cheese count, too) you can get the proper amino acid balance. All meat and fish are high in protein, so choose based on saturated fat and other factors.

If you do stick to plants, eat a variety of rice, wheat, and legumes, especially beans, says dietitian Molly Kimball. You can’t go wrong with any of them, and many also contain important nutrients. Lentils, for instance, are high in iron. So are soybeans, notably edamame. Adzuki and navy beans are saturated with zinc. Split peas, kidney beans, and lima beans contain tons of protein, and so do sprouted beans (at their best in the week they start to sprout). For more protein info than you can possibly absorb, take a look at The Protein Counter, by Annette B. Natow and Jo-Ann Heslin.

• Mistake: Not getting the right nutrients. While a fruit- and veggie-rich meat-free diet can have abundant antioxidants like vitamins E and A, it can be thin on other vital nutrients like B-12, zinc, and some amino acids. Deficiencies here can lead to stunted growth, dulled thinking, memory loss, and fatigue.

• How to fix it: Taking a good daily multivitamin, plus a B-complex with plenty of riboflavin, B-12 (only 2.5 micrograms necessary), and folic acid (400 mcg a day, or roughly five servings of fruits and leafy greens) is a good way to fill in the gaps. Also supplement zinc (RDA is 15 mg/day). Flaxseed oil and seeds and walnuts can provide amino acids and omega 3-fatty acids. Kelp is another vegetarian source. But by far the most efficient is fish oil—1 to 2 grams a day. “You have to have the fish oil—nothing else matters,” says Garry Gordon, a Payson, Arizona-based physician and coauthor of The Omega-3 Miracle, who sees a correlation in his elderly patients between vegetarian-related nutritional deficiencies and higher rates of illness.

• Mistake: Eating too much. Since vegetarians often load up on snack foods and sugary carbohydrates to satisfy cravings and get missing calories, they can actually overload on empty calories. Physician Kathleen Wilson notes that an unbalanced vegetarian diet can put some people at a higher risk of diabetes, as well as lead to
obesity.

• How to fix it: Eat a high-fiber snack, like an apple, before a meal or a big salad along with your meal to take the edge off your hunger. Adding small amounts of fat, such as cheese, olive oil, or almond butter, to your meal can also make you feel full, says New Orleans dietitian Molly Kimball. If you’re prone to snacking, keep munchies on hand that contain the minerals or vitamins you’re trying to get in a balanced diet, like baby carrots, almonds, edamame, and whole grain trans-fat-free-crackers.

Veggie Power: Helpful Sites

Run a Google search on “vegetarianism” and you could get more than 350,000 results. Clearly there’s a lot to say about it, but where do you go for truly useful help on planning a healthy vegetarian diet? We culled through the listings and came up with four recommendations, and tossed in a blog devoted to the vegetarian debate just for the fun of it.

• Veg Blog (vegblog.org): Debates the politics and paradigms of eating meat-free. Entries cover everything from scientific news on animal behavior to media-watch coverage of nutrition in the news. This is where to stay abreast.

• The International Vegetarian Union (ivu.org): Has promoted vegetarianism since 1908. A multilingual site devoted to news and information about the vegetarian lifestyle. This site will aim to convert you.

• VegSource (vegsource.com): Everything you wanted to know about vegetarianism. This is the information resource for the veg scene, complete with links to dietitians, tips on pressure-cooking zucchini, and legal updates.

• The Vegetarian Society of the UK (vegsoc.org): Offers practical information from diverse lifestyle perspectives. Info ranges from animal rights to the environment. A recent feature? How to open a vegetarian restaurant.

• The American Dietetic Association (eatright.org): Mainstream advice on eating right. This is the official viewpoint on nutrition and balance—from standards and meal plans to caloric counts.