CHICAGO — Dr. Kim Williams thought he followed a heart-healthy diet: He avoided red meat and fried foods. He ate his chicken breast without the skin.
Then in 2003, the Chicago cardiologist realized his level of LDL, the so-called "bad" cholesterol, was too high. Inspired by a patient's success with a plant-based diet, Williams began using "meat substitutes" for protein. Within six weeks, he says, his LDL level plummeted almost by half into the healthy range.
Now a firm believer in the vegan way of eating — no meat, fish, eggs or dairy — Williams wrote an essay on the benefits of a plant-based diet for cardiac patients, which kicked off yet another rancorous debate over how people should eat to best protect their hearts.
Supporters praised Williams, chief of the cardiology division at Rush University Medical Center, for highlighting the widely accepted health benefits of eating fruits and vegetables. Critics grumbled about the "food police" and questioned whether a physician with such an influential position should be advocating for a diet that many view as extreme.
"Doctors who recommend a vegan diet are experimenting on their patients," said Dr. Jack Wolfson, an Arizona cardiologist who encourages "Paleo" nutrition, or eating unprocessed foods that can be hunted or gathered, including meat.
Williams says he's surprised by the polarized reaction and dismisses the idea that veganism is "experimental" given the considerable data gathered on people who eat that way. But he's also eager for large-scale, randomized trials and acknowledges there are many ways to eat more healthfully.
"Anything someone does to move away from the standard American diet will make a huge difference in terms of diabetes, hypertension, obesity and heart disease," said Williams, referring to the nation's high consumption of sugar, saturated fat and processed foods.
"Given the health implications of diet, putting the issue in front of people who live with an epidemic of heart disease is not a bad thing," he added.
The debate underscores the personal and complex nature of nutrition science. Though fruits and vegetables are part of any healthy diet, there's no consensus on the best way to eat, causing endless confusion and frustration for consumers.
Williams' statements in support of a plant-based diet — an option naturally low in saturated fat — came not long after a study published in March famously challenged the conventional wisdom that people who consume more saturated fat are at higher risk of heart disease.
Vegan products are easier than ever to find in stores and restaurants, reflecting the diet's increasing popularity. The trendy high-protein, high-fiber Paleo or "caveman" diet includes grass-produced meats and seafood and excludes grains, potatoes and legumes.
Among those who choose a plant-based diet, many cite health reasons, but environmental and ethical concerns are more important for others.
Vegans eat no animal products — including meat, fish, eggs, dairy and, often, honey. But though Williams eats like a vegan, he doesn't describe himself that way because of the term's other connotations. Many vegans avoid all animal-based products, including leather, fur, silk, wool and some soaps and cosmetics, for ideological reasons.
"It just happens that my view on a plant-based diet agrees with those groups," Williams said. "For me, it's a health and diet statement."
Vegetarians generally abstain from eating animal flesh of any kind. Dairy is usually OK, and some eat eggs. Pescetarians are vegetarians who also eat fish and seafood. The term flexitarian refers to people who primarily eat plant-based foods but might indulge when they smell bacon.
Well-planned vegetarian diets, including vegan ones, are nutritionally adequate and appropriate for nearly everyone, including pregnant women and elite athletes, according to the Academy of Nutrition and Dietetics. The National Institutes of Health says a varied vegetarian diet can reduce the risk of obesity, heart disease and Type 2 diabetes, as well as lower blood pressure.
But experts also say vegans and vegetarians who aren't careful can wind up consuming a high-carbohydrate diet lacking in basic nutrients.
"You can eat white bread and Oreos, a bunch of Boca burgers, and a gallon of sweetened soy milk and be 'vegan,'" Dr. Ashwani Garg wrote in response to Williams' essay on MedPage Today.
Garg, a family medicine practitioner in suburban Hoffman Estates, said in an interview that he commends Williams for raising the issue of nutrition but would rather see him promoting plant-based nonprocessed foods in general.
Cardiologist Neil Stone, medical director of the vascular disease center at Northwestern Medicine's Bluhm Cardiovascular Institute, said the vegan diet hasn't been conclusively shown to be better than other healthful eating patterns, including the DASH diet and the Mediterranean-style diet. Both emphasize fruits, vegetables, nuts, beans and seeds, but they differ in the amount of recommended fats.
Vegetables are also the foundation of Paleo nutrition, "but everyone should be eating some amount of meat and/or seafood on a weekly basis," Wolfson said. "I'm talking about free-range, grass-fed, healthy animals," he added. "I'd never tell anyone to eat a burger with a bun."