Miami cardiologist Dr. Arthur Agatston published his South Beach Diet book in 2003. His new book promotes a four-point plan of diet, workout, diagnostic tests and medications for optimum cardiac health.

MCT / MARSHA HALPER

It’s a new year, and Dr. Arthur Agatston, the man behind the ubiquitous South Beach Diet books, is putting himself back on his diet.

His son, Evan, 23, was home from law school for the holidays, watching the football bowl games with him, and the doctor packed on a few pounds from “those dark chocolate things my wife brings home for guests even though I ask her not to.” He adds: “Then Sari [his wife] tells me that if I don’t take off those pounds, I’ll only be able to promote my book on the radio.”

His new book, The South Beach Heart Health Revolution (St. Martin’s Griffin, $14.95), went on sale this month. It goes well beyond his “good-carb, good-fat” diet books, promoting a four-point plan he says can create a major change in Americans’ heart health.

He asserts: “I believe we have reached a point where the great majority of heart attacks and strokes can be prevented.”

“Prevented?” Heart disease is the number one killer, accounting for one in five deaths in the United States; strokes, number three.

Yes, he knows that. The problem?

A faulty model in treating heart disease, he says, a model based on treating heart disease after it occurs through angioplasties and bypass operations, rather than on preventing it in the first place. It’s a hard model to break, he says, as it requires rethinking traditional medical practices, focusing on prevention instead of surgery. Changing the model also would drastically cut lucrative income sources — bypass surgeries and angioplasties — for doctors and hospitals.

“There’s a lot of inertia in medicine,” he says. “People have been doing things for years and are slow to change. And if there is a financial disincentive, that adds to the inertia.”

NOT SO FAST, SAY other cardiologists.

Heart disease is still “a problem of epidemic portions,” says Dr. William O’Neill, executive dean of clinical affairs at the University of Miami Miller School of Medicine. “The reason that there are so many cardiologists is not because it’s lucrative, but because there are so many patients to treat.”

And while diet, exercise and smoking all contribute to heart disease, so does genetics, he says.

Dr. Marion Nestle, professor and former chairwoman of the Department of Nutrition, Food Studies, and Public Health at New York University, challenges Agatston’s assertion that “a great majority” of heart attacks and strokes can be prevented.

“Great majority? I’d like to see the evidence,” she said. “If calories and saturated fat are reduced, the risk of heart disease and stroke should decline. But I’m not convinced that most people can cut calories this way.”

To Agatston, prevention is centered on four key steps:

•Diet: By maintaining a healthy weight, you can lower your cholesterol, triglyceride levels, blood pressure — the key factors that contribute to heart disease. Of course, he says, his diet is the place to start.

•Workout: A comprehensive aerobic, stretching and strengthening workout program will lower your risk of heart disease; his earlier books had said that, while exercise is beneficial, it isn’t essential to weight loss under his diet.

•Diagnostic tests: Even healthy patients should consider CT heart scans and advanced blood tests to check for arterial plaque, which Agatston calls the strongest signal of pending heart trouble.

•Medications: Too often, he says, medications to lower cholesterol and blood pressure levels are not prescribed — only about 50 percent of Americans at high risk for heart disease who could benefit from a cholesterol-lowering medicine are actually receiving one. Doctors, under pressure to see patients quickly, he says, don’t always ask the questions to determine whether drugs are needed.

AGATSTON, WHO TURNED 60 on Jan. 22, was raised on Long Island, the son and grandson of doctors, attended med school and practiced briefly at New York University. He came to Mount Sinai Medical Center in Miami Beach in 1979, where he is director of the Non-Invasive Cardiac Lab and of Cardiac Rehabilitation.

At Mount Sinai he helped develop an ultrafast CT scan for measuring calcium in coronary arteries as a predictor of heart attack and stroke — scans that today are measured on the “Agatston Scale.”

But as he treated patients, he saw that their attempts to lose weight on the low-fat, high-carb diet recommended by the American Heart Association were failing.

“It was frustrating. In the ’80s and early ’90s, cardiologists were not counseling patients to diet because the guidelines didn’t work,” he said. He decided to experiment with his own diet, with the help of nutritionists.

Agatston concluded that America’s high obesity rates were caused by over-processed foods that were digested too quickly, raising blood sugar levels, creating insulin swings and making people hungry again too soon.

So the premise of Agatston’s first book, The South Beach Diet (Rodale Press, 2003), was simple: Avoid “bad” carbs and “bad” fats in favor of “good” carbs and “good” fats, plus eat lean protein.

Good carbs, the complex carbohydrates in whole wheat bread and unprocessed fruits and vegetables, digest slowly and keep one feeling full. Good fats, the monounsaturated ones like canola and olive oil and especially omega-3-rich fish oils, improve the flexibility of arteries rather than clogging them.

It clicked. The South Beach Diet became a number one New York Times bestseller, and the six books in the series have sold 22 million copies.

But his next move might have been too fast. With Kraft Foods, in 2005 he brought out frozen South Beach Diet dinners.

Critics pounced on the foods’ sodium count — 950 to 1,530 milligrams per serving. The American Heart Association says the average person should not have more than 2,000 milligrams of sodium a day.

Says Agatston: “Our first priority was to get rid of bad fats and starches, but the foods we made had to be palatable.”

Still, he worked on the problem with Kraft, and today the South Beach Diet frozen foods average 460 to 910 milligrams of sodium. “It’s a huge improvement,” Agatston says.

With Agatston’s new book, experts’ views are mixed.

DR. MICHAEL OZNER, a cardiologist and author of The Miami Mediterranean Diet (2005, Greenleaf Book Group), criticizes Agatston’s diet as too high in saturated fat.

“There’s no clinical trial evidence that the South Beach Diet will reduce the risk of heart attack or stroke,” says Ozner. “I can drown you in studies that show the Mediterranean diet will decrease heart attack, stroke, diabetes, even Alzheimer’s.”

Agatston acknowledges that, while some parts of his diet have been tested in small, short-term studies, it never has been judged in a long-term study with thousands of participants in which neither patient nor doctor knows who is on the diet and who is not.

But he dismisses Ozner’s charges: “The idea of our diet having too much fat and protein has not been an issue in the literature,” he said. Ozner also questions Agatston’s statement that patients should consider CT heart scans to check for calcium and plaque. The tests were created in part by Agatston, and their measure of coronary calcium is called the Agatston Score.

Says Ozner: “The radiation exposure is significant. It raises your life risk of cancer. There’s no dose of radiation that’s safe. It’s cumulative.”

He cites a 2004 study in which Columbia University researchers conclude that a single, full-body CT scan of a 45-year-old adult would increase his lifetime cancer mortality risk by 0.08 percent.

“That’s with a total body scan,” Agatston says. “A heart scan has much less radiation. It’s the best overall predictor of who’s going to have a heart attack.”

OTHER EXPERTS LAUD the diet.

“The South Beach Diet is better than Atkins,” says Claudia Gonzalez, a dietitian and spokesperson for the American Heart Association. “It has more whole grains, vegetables and fruits, and it’s careful in terms of the fats it recommends.”

The diet has boomed. Bill and Hillary Clinton speak of having lost weight on it. Oprah praises it. Agatston has appeared on The Early Show on CBS, Good Morning America and 20/20. Between appearances, he carries on his private cardiology practice in Miami Beach.