A team of cardiologists has reviewed the best scientific evidence on the health benefits of popular diet plans and has reached some conclusions that may help settle the debate about which plan is best for both weight loss and cardiovascular health.
The bad news is, no one diet offers the perfect solution.
The good news is, research proves that by combining the best parts of several plans and adopting an active lifestyle, individuals can keep their ideal weight or gradually lose weight while improving and maintaining long-term cardiovascular health.
The results of the research review are published on-line and in the May 3 issue of the Journal of the American College of Cardiology. The team included principal investigator Laurence Sperling, MD, FACC, professor of medicine at Emory University School of Medicine and director of the Emory Heartwise Risk Reduction Program and lead author Parin Parikh, BA, from the Johns Hopkins Ciccarone Preventive Cardiology Center. Other contributors included Michael C. McDaniel, MD and Joseph I. Miller, MD, from Emory School of Medicine, M. Dominique Ashen, PhD, CRNP and Roger Blumenthal, MD, FACC, from Johns Hopkins and Vicki Chan, BS, from the University of Chicago.
Obesity in the U.S. has increased by 61 percent since 1991 and an estimated 300,000 adults in the U.S. die from obesity-related causes each year, even though the American Heart Association recommends that adults consume no more than 30 percent of their calories from fat, and despite the promotion of a variety of popular diets.
"The obesity epidemic has led to a variety of well-known diets, but consumers and physicians often receive conflicting and complex messages about which plan offers the best health benefits, and sometimes this leads to extremes," says Dr. Sperling. "We felt it was important to review the scientific literature so physicians could better counsel their patients on how these different eating plans stack up."
Portion size and total calorie intake are more important than any individual foods a person eats, Dr. Sperling says, and the basic principle of weight loss remains the same: people lose weight when they burn more calories than they consume.
Among the study's conclusions: a low-carbohydrate diet can lead to short-term weight loss, but the long-term benefits for weight loss and cardiovascular health are not yet proven. Very-low-fat diets can improve cardiovascular health but are difficult to sustain over time and may be impractical in large populations. No clinical trials have yet evaluated the effects of diets based on a low glycemic index, such as the South Beach Diet, but at the least this type of diet leads to the consumption of better kinds of fats, lean protein, fruits, vegetables, and whole-grain foods instead of refined carbohydrates.
Scientific studies have proven that the Mediterranean Diet is beneficial for cardiovascular health. This diet includes many plant foods, including fruits, vegetables, breads, cereals, potatoes, beans, nuts, and seeds, minimally processed foods, olive oil, low to moderate amounts of dairy products, fish, poultry, and eggs, red meat only rarely, and wine in low to moderate amounts with meals. The DASH Diet, which similarly emphasizes fruits, vegetables, low-fat dairy, whole grains, nuts, fish, and poultry, along with reduced fats and reduced consumption of red meats and sweets, helps preserve cardiovascular health by reducing blood pressure.
The bottom line, say Dr. Sperling and his colleagues: decrease carbohydrates, especially refined and high-glycemic-index carbs, increase consumption of fruits, vegetables and whole grains, increase intake of polyunsaturated fats by consuming more plant oils and fish, and consume moderate amounts of low-fat dairy products and nuts.