Although there are many major dietary approaches for protecting health, experts generally agree on the following recommendations for heart protection:

Choose fiber-rich food (whole grains, legumes, nuts) as the main source of carbohydrates, along with a high intake of fresh fruits and vegetables. Walnuts in particular have cholesterol-lowering properties and are a good source of antioxidants and alpha-linolenic acid.
Avoid saturated fats (found mostly in animal products) and trans fatty acids (found in hydrogenated fats and many commercial products and fast foods). Choose unsaturated fats (particularly omega-3 fatty acids found in vegetable and fish oils).
In selecting proteins, choose soy protein, poultry, and fish over meat. A 2006 study found that soy does not help improve cholesterol. However, experts still recommend it as a heart healthy food choice.
Weight control, quitting smoking, and exercise are essential companions of any diet program.

After embarking on any heart healthy diet, it generally takes an average of 3 to 6 months before any noticeable reduction in cholesterol occurs, although some people have reported better levels in as few as 4 weeks. An intensive program may be necessary to achieve any significant improvements in cholesterol levels and to reduce heart risk factors.

[For more information, see In-Depth Report #43: Heart-healthy diet.]

Therapeutic Lifestyle Changes (TLC) from the National Cholesterol Education Program

Dietary guidelines from the National Cholesterol Education Program recommend:

Choose five or more servings of fresh fruits and vegetables and six or more servings of whole grains and legumes. Soluble fiber is preferred (from cereal grains, beans, peas, legumes, and many fruits and vegetables).
Fats can be up to 35% of daily calories, but no more than 7% should be from saturated fat. (People with high triglycerides or low HDL or both may need a higher fat intake.) Choose fats containing unsaturated fatty acids (from vegetables, fish, legumes, and nuts). Choose margarines containing sterols or stanols (such as Benecol or Take Control). Avoid trans fatty acids found in commercial products as much as possible.
Proteins should be limited in general to fat-free and low-fat milk products, fish, legumes, skinless poultry, and lean means.
Limit cholesterol intake to less than 200 mg per day.
Maintain healthy body weight and a healthy level of physical fitness.

Mediterranean Diet

The Mediterranean diet is rich in heart-healthy fiber and nutrients, including omega-3 fatty acids and antioxidants. The diet consists of fruits, vegetables, and unsaturated "good" fats, particularly olive oil. Olive oil has been associated with lower blood pressure, a lower risk for heart disease, and other benefits for people with type 2 diabetes.

There are several variations to the Mediterranean diet but general recommendations include:

Limit red meats
Drink one or two glasses of wine each day if alcohol is enjoyable and there are no reasons to restrict its use
Limit dairy products
Eat moderate amounts of fish and poultry. Fish is the diet's main protein source. Some studies suggest that fish is the primary heart-protective ingredient in this diet.

Low Carbohydrate Diets

Diets that restrict carbohydrate intake include the Atkins diet, South Beach, The Zone, and others. A 2006 review of low-carbohydrate diets found that they did help weight loss in the short term. However, while these diets appeared to lower triglyceride and raise HDL (“good”) cholesterol levels, they also raised overall and LDL (“bad”) cholesterol levels. There is not yet enough evidence to indicate whether the good heart effects of these diets outweigh the bad effects. At this time, experts do not recommend low-carbohydrate diets for heart disease prevention or for people with type 2 diabetes.

Low-fat Diets

Dietary guidelines recommend keeping total fat intake to 25 – 35% of total daily calories, with saturated fat less than 7% of calories. Low-fat diets generally restrict fat intake to 20% or less of total daily calories. The Ornish program, which is recommended for some heart disease patients, limits fats even more drastically. It aims at reducing saturated fats as much as possible, restricting total fat to 10%, and increasing carbohydrates to 75% of calories.

In 2006, the largest study to date on low-fat diets found that they did not help prevent heart disease or cancer. Women in the study reduced their fat consumption to 24 – 29% of total daily calories. Some critics say that the study did not do enough to distinguish between good types of fats (monounsaturated and omega-3 polyunsaturated) and bad fats (saturated and trans fats

DASH Diet

The DASH diet (Dietary Approaches to Stop Hypertension) is proving to help lower blood pressure. Results are sometimes seen within a few weeks. Restricting sodium improves results. The diet appears to have antioxidant effects and may help lower LDL cholesterol levels, although beneficial HDL levels also decline. This diet is not only rich in important nutrients and fiber but also includes foods that contain far more electrolytes, potassium, calcium, and magnesium, than are found in the average American diet.

The DASH diet recommends:

Reduce saturated fat (but include calcium-rich dairy products that are non- or low-fat).
When choosing fats, select monounsaturated oils, such as olive or canola oils.
Choose whole grains over white flour or pasta products.
Choose fresh fruits and vegetables every day. In one study people who increased their intake of fruits and vegetables experienced a drop in blood pressure after 6 months. Many of these foods are rich in potassium, fiber, or both which may help lower blood pressure.
Include nuts, seeds, or legumes (dried beans or peas) daily.
Choose modest amounts of protein (preferably fish, poultry, or soy products).

Slight changes to the DASH diet might help lower blood pressure even more, as well as improve cholesterol and lipid levels. Researchers reporting in the Journal of the American Medical Association and at the 2005 American Heart Association meeting said that replacing some carbohydrates in the DASH diet with more protein or monounsaturated fats may help reduce heart disease risk factors.

[For more information, see In-Depth Report #14: High blood pressure.]