Healthy Eating for a Healthy Heart

• The heart of the matter
  • The impact of diet
  • The impact of weight
  • Why lifestyle changes help
• Nutrition basics
  • Facing the fats
  • Carbohydrates: Avoid refinement
  • Proteins: More than “meats” the eye
  • Beverages: Drink to your health
  • Other noteworthy nutrients
• Losing weight to help your heart
  • Do you need to lose weight?
  • Advice from successful losers
  • Get a hearty start
  • Weight-loss diets and your heart
• Putting theory into practice
  • Shop smart
  • Choose convenience foods wisely
  • Eat out the healthy way
• Recipes
  • Breakfast foods
  • Lunch and dinner entrees
  • Side dishes, salads, and soups
  • Snacks
  • Desserts
• Sample meal plan for a week
• Resources
• Glossary

Weight-loss diets and your heart

A number of diets have been touted for helping people both lose weight and improve heart health. The growing consensus on weight-loss diets in general (regardless of any health issues you may have) is that specific components of the diet matter less than how well you can stick to the diet plan. To help your heart, the Mediterranean diet has a long and strong track record.

A study led by Harvard researchers, published in 2009 in The New England Journal of Medicine, reaffirmed the weight-loss story. The multisite study compared four different low-calorie diets (high fat, high protein; high fat, average protein; low fat, high protein; and low fat, average protein) in 811 overweight adults. Although all the participants lost an average of about 13 pounds in the first six months (about 7% of their initial weight), they started to regain at the one-year mark. After two years, average weight loss was the same in all groups—about 9 pounds, on average.

Following are brief summaries of popular diets and their effects on heart disease and related risk factors.

Very low-carbohydrate diets. This protein-rich eating style, popularized by the Atkins diet, strictly limits carbohydrates, including most fruits and vegetables, but allows free rein on calories and fat. The short-term weight loss often seen with this diet has been attributed to a boost in fat metabolism and its satiating properties—people usually don’t feel hungry on this diet. A study that combined results from six different trials of very low-carb diets found that while people lost more weight on this diet than on a comparison diet (usually a low-fat, low-calorie diet) over six months, the weight loss among the different diets was the same after one year. Of note, LDL cholesterol levels were the same in people on the different diets, while HDL and triglyceride levels improved at six and 12 months on the very low-carb diets. However, no studies have studied whether an Atkins-style diet can lower the rate of heart disease and death.

Low-carbohydrate diets. The South Beach diet is perhaps the best known of the low-carb diets, which also include the Zone diet and Sugar Busters. Many are based on the glycemic index (see “Glycemic index and load,” page XX) and recommend healthy (monounsaturated and polyunsaturated) fats. A trial that compared the South Beach diet with the National Cholesterol Education Plan (NCEP) diet for 12 weeks found no lipid level differences between the two groups, but the South Beach dieters lost an average of about six more pounds than the NCEP group. A year-long trial comparing the Zone diet with other three other diets revealed comparable weight loss and lipid improvements among all four plans. Large population-based studies have linked lower HDL cholesterol levels (a risk factor for heart disease) with consumption of foods that have high glycemic index values. But there aren’t any studies documenting lower rates of heart disease among people on low-carb diets.

Very low-fat diets. The rationale for these diets stemmed from the connection between saturated fat and atherosclerosis. The most-studied version, the Ornish diet, is a vegetarian diet that restricts fat to just 10% of total calories—far lower than the 30% consumed by most Americans. The Ornish program also integrates exercise and meditation along with smoking cessation, and advises dieters to avoid alcohol and caffeine. A five-year study of men with heart disease showed the diet cut LDL cholesterol by about 20%, with no effect on HDL and triglycerides. The men lost an average of nearly 13 pounds compared with no change in the control group. The findings also revealed a 91% decrease in angina symptoms after a year and a 72% decrease after five years among men following the diet. But men in the control group experienced a 186% increase in angina symptoms after one year. Within five years, the control group’s angina symptoms had decreased 36%, but that was attributed to their higher rates of angioplasty and bypass procedures.

The Mediterranean diet. The inspiration for this diet dates back to the 1970s, with the publication of the Seven Countries Study, which showed low heart disease rates in Greek islanders despite their high fat intakes (35% to 40% of calories). The diet features mainly vegetables, fruits, whole grains, and fish as well as some dairy products (mostly cheese or yogurt), a small quantity of meat and poultry, and a regular but moderate amount of red wine. The higher levels of healthy monounsaturated fats (found in olive oil) and polyunsaturated fats (found in fish) in the Mediterranean diet replace the less healthy saturated and trans fats—a practice proved to help lower cholesterol levels. Yet some studies of people on the diet found improvements in LDL, HDL, and other factors associated with heart disease risk, while others showed only minimal benefits.

However, when it comes to cutting heart disease risk, the Mediterranean diet is a clear winner. One study involving more than 22,000 adults in Greece revealed that people who closely followed a Mediterranean diet had a 33% lower risk of heart disease. The Lyon Diet Heart study, which included 300 people with heart disease, documented a 73% lower risk of fatal and nonfatal heart attacks among those following the diet for 27 months. The first U.S.-based study of the diet confirmed that the more closely people followed the Mediterranean eating style, the lower their risk of dying from either heart disease or cancer. A 2009 study examining the relative importance of each component of the diet found that its longevity-promoting benefits stemmed mainly from drinking wine with meals, eating little meat, and eating lots of vegetables, fruits, nuts, olive oil, and legumes. (Eating lots of fish, seafood, and cereals, as well as eating small amounts of dairy products, didn’t seem to make much of a mortality difference.) Finally, a two-year-long study found that people lost more weight on the Mediterranean diet than a low-fat diet.