Sticking to a Heart Healthy Diet with David Katz, MD

Confused about everything from healthy food to hypertension? Then read on!

WebMD Weight Loss Clinic - Live Events Transcript

Reviewed By Kathleen Zelman, MPH, RD, LD

What's for dinner? Good question. If you're confused about the low-fat claims on food labels, the safety of today's popular diets, or the effects of certain foods on your health, from hypertension to heart disease, read what David Katz, MD, author of The Way to Eat: A Six-Step Path to Lifelong Weight Control, had to say on WebMD Live.

The opinions expressed herein are the guest's alone and have not been reviewed by a WebMD physician. If you have questions about your health, you should consult your personal physician. This event is meant for informational purposes only.

Moderator: Welcome, Dr. Katz. Can you give us some guiding principles about eating for heart health?

Katz: I certainly can. Good news is that eating for heart health is the same as eating for overall health. Not all that long ago there was consideration of many different diets for different medical conditions. But, of course, the same individual who is at risk for heart disease also is concerned with weight control, perhaps a risk for diabetes and overall health. The basic principles of a heart-healthy diet are the principles of a health-promoting diet. Namely the diet should be:

  • Rich in whole grains, vegetables, and fruit
  • Moderation and balance are very important
  • Both saturated and trans fats should be minimized by limiting intake of:
    • Fast food
    • Processed snack food
    • Processed baked goods
    • Other pre-packaged products
  • Fat in the diet should come primarily in the form of polyunsaturated and monounsaturated by eating a diet rich in:
    • Vegetables
    • Seeds
    • Nuts
    • Grains
    • Fish
  • And by using healthy cooking oils such as olive oil and canola oil

The overall fat content of the diet need not be severely restricted, provided the fat sources are the right ones. Ultimately, the only way a diet can promote lifelong health is if it's a diet you can stick with for a lifetime. A heart-healthy diet is not a diet to get on and get off, but a way of life.

Member: I know of a small study where they compared a high avocado diet with the AHA cardiac diet. They both lowered the cholesterol total, but the HDL did not drop with the avocado diet. What are your thoughts on "the good fats"?

Katz: I believe that fat in the diet is important to heart health in terms of quantity and quality. The typical American diet is slightly excessive in total fat. But more importantly, it derives far too much of its fat from saturated and trans fatty acids. Avocado is one of only two fruits high in fat. The other is the olive. Both of these fruits are rich in health-promoting monounsaturated fat. There is evidence from clinical trials that a Mediterranean diet rich in monounsaturated fat can significantly lower the risk of heart attack in individuals with established heart disease. There is evidence as well that fat restriction can lower the risk of heart attack.

Anthropologists tell us that our ancestral intake of fat was approximately 25% of total calories, and that almost all of the fat they ate was mono- or polyunsaturated. Further, the meat consumed by our ancestors was an excellent source of health-promoting omega-3 fatty acids. In my view, if one combines the best of modern science with insights about ancestral dietary pattern, it points to a diet that provides maximal cardiac benefit. Such a diet helps to lower cholesterol while maintaining high levels of HDL.

While the American Heart Association Diets do represent an improvement over prevailing dietary habits in the U.S., we are definitely learning that we can do even better. So enjoy those avocados. Just exercise portion control because they are high in calories.

Member: What is the better source of omega-3 oils: Walnuts or fish? Any other non-animal sources?

Katz: Yes. The single best plant source of omega-3 fatty acids is flax seed. Flax seed also has the benefit of being rich in fiber and lignans, which are phytoestrogens and possibly cardio-protective. However, all plant sources of omega-3's provide alpha linolenic acid. The health benefits of omega-3's are particularly associated with docosahexanoic acid and eicosapentanoic acid. These long-chain omega-3's are found in fish and marine animals. We can manufacture them from alphalinolenic acid, but do so with variable and often limited efficiency. Thus, for people willing to consume animal products, the best evidence supports the use of fish oil for cardiac benefit. The recommended dose for prevention of heart disease is one gram twice daily.

For strict vegetarians one tablespoon of flax seed oil or one tablespoon of ground flax seed daily is the best substitute. Walnuts do contain omega-3's in lower doses but also provide fiber, other nutrients, and mono-unsaturated fat. They certainly are a heart-healthy food.

Member: Do fish oil supplements provide the same benefit as fish eaten?

Katz: Fish is an excellent source of high quality protein that is important to overall health. Fish oil capsules, of course, provide only the oil and do not constitute a whole food. But with regard to omega-3 fatty acids the supplements are an even more reliable source than the fish from which they are derived. This is because the omega-3 content of fish varies with the diet of the fish. There is some evidence for example that the omega-3 content of farm raised salmon is lower than that of their wild cousin. Farm-raised salmon are fed I suppose something like Purina Salmon Chow while wild salmon eat algae that is a rich source of omega-3's. Fish oil supplements of high quality provide a reliable dose of omega-3's with the additional benefit of having been purified of heavy metals, such as mercury.

If I may end this answer with a digression, it's interesting to note omega-3 fatty acids are widely deficient in the American diet. It makes sense we need this class of nutrients, not because our ancestors ate so much fish, but because like the farm raised salmon, other domesticated animals have had omega-3's removed from them by changes in their diet. The flesh of deer and antelope is low in total fat but relatively rich in omega-3's. In contrast, domestic cattle are high in total fat and provide almost no omega-3's. The meat we eat today is nothing like the meat our ancestors ate.

Member: How do you know the fish you are eating, or fish oil capsules actually contain omega-3 if farm-raised do not have a high level of omega-3 in them?

Katz: It's almost impossible to know the exact omega-3 content of fish; however in general, salmon are an excellent source. Even though farm-raised salmon have less omega-3 at times than wild salmon, they are still among the leading whole food sources. Other fatty fish, especially mackerel, are good sources as well, as are tuna, swordfish and halibut.

With supplements it's much easier to evaluate the exact omega-3 content. Consumer Labs is a company that conducts independent audits of nutritional supplements. Their reports are on Most of the omega-3 supplements on the market do pass their tests for quality assurance, but not all consistently report correct doses on the label. Check out this resource for guidance regarding locally available products with reliable dosing.

Member: Can flax seed oil replace not eating fish in the diet?

Katz: As mentioned earlier, the best source of cardio-protective omega-3's is fish oil. But for a vegan, flax seed is definitely the best alternative. So the short answer is, I think so. Note that while we have clinical trial evidence to support the benefit of fish oil, a comparable benefit from flax seed oil is at this point based largely on educated inference.

"Popular diets that use a single class of nutrients as a scapegoat for epidemic obesity are putting up a dangerous and distracting smoke screen."

Member: Would you go so far as to tell people to avoid red meat from grocery stores or eat them in moderation, such as once a week?

Katz: I think that's an excellent question. In my view the best way to answer it is to say that you are the boss. It's your life. It's your heart. And it's your diet. If you love red meat, giving it up entirely may be a hardship for you. If this is so, moderate intake of red meat in the context of an overall health promoting dietary pattern is the way to go. If, however, red meat is not that important to you, there is no health disadvantage in giving it up entirely. A well-balanced vegetarian diet is known to be very heart healthy, and such a diet modified to include fish is perhaps the most heart-healthy diet of all.

However, lifelong health benefits cannot be derived from a diet you are not comfortable staying on for a lifetime. Make choices that balance health promotion with enjoyment of food and factor in your personal priorities to make sure your diet is indeed a source of lifelong health.

Member: Is there a way that you can reverse or help with mild mitral valve prolapse?

Katz: I am not aware of definitive evidence that dietary intervention affects the integrity of the mitral valve or the mitral valve ring. However, there is interest in the ability of at least one nutrient supplement to fortify cardiac tissue and by this means it could potentially help ameliorate mild mitral valve prolapse. The nutrient in question is co-enzyme Q-10, generally recommended at a daily dose of one to two milligrams per kilogram. Other than this, regular physical activity would be prudent as this certainly helps to optimize the integrity of all cardiac tissues.

Member: Is there a complete vitamin out that is the best for the heart?

Katz: Most conventionally trained physicians feel that almost any quality-controlled multivitamin with minerals and antioxidants is good for overall health and heart health. Many naturopathic physicians, however, emphasize the benefits of organic supplements or high potency supplements taken in divided doses. Many of my colleagues in alternative medicine recommend Multi-Nutrients by Vital Nutrients. For those not averse to taking several capsules daily, this is an excellent product.

However, one should not let perfect be the enemy of good. The simplicity of a single supplement can be desirable. If inclined toward simplicity, widely available multivitamins such as Centrum are acceptable. Perhaps most important, a supplement is just that -- not a substitute for a health promoting dietary pattern. The benefits of eating well are not to be found in any pill or combination of pills.

Moderator: What is your take on carbohydrates in the diet? What choices should we be making for heart health?

Katz: An excellent question, too, especially because weight control is very important to heart health. Everyone has heard about the Atkins diet, including reports of rapid weight loss. However I must point out that cancer, cholera, tuberculosis, and AIDS also produce rapid weight loss. That does not mean they are good for you. In fact these conditions not only cause weight to plummet, they lower cholesterol as well. This serves to highlight the importance of thinking about overall health when making dietary choices for weight control.

Popular diets like Atkins drastically oversimplify what the term carbohydrate means. I quite agree the typical U.S. diet contains far too much processed starch and refined sugar. The way to fix this, however, is to eat more whole grains, fruits, and vegetables -- not to replace processed sugar with saturated and trans fat. In general the best evidence we have supports a diet that is based largely on sources of complex carbohydrates with the right balance of fat and moderate, overall protein.

Popular diets that use a single class of nutrients as a scapegoat for epidemic obesity are putting up a dangerous and distracting smoke screen. We struggle with our weight because we take in more calories than we need and can control our weight with the very same diet that serves to optimize our health. This requires learning skills and strategies for exercising portion control and creating a safe nutritional environment. There are few sources for such information. Consider referring to my recently published book, The Way to Eat (You can find out more at It details the skills and strategies needed to get around the many obstacles we encounter every day in our efforts to eat well and control our weight. Empowered with these skills and strategies bad diets will lose their appeal.


According to the USDA, there is no difference between a “portion” and a “serving.” See Answer

Member: I have battled weight all my life. I say I have lost three and a half people in my life. I am fat again. Would you suggest I talk to a nutritionist before I venture to another diet?

Katz: My advice to you first and foremost is that you should never go on a diet again. I am sorry you have had this experience with your weight. It is extremely common. I've seen it countless times in my patients over the years. One thing I want to tell you is that it's not your fault -- 65% to 80% of adults in the U.S. are overweight. This tells us it's a population-wide struggle, not just the struggle of any individual.

In fact, I frequently equate our weight control difficulties with the plight of polar bears in the Sahara Desert: We are naturally designed for a high level of physical activity and having barely enough to eat. We live in a world where it's easy to be inactive and to overeat. Until or unless you learn how to resist the challenges of this "toxic" nutritional environment we live in, you will inevitably struggle with your weight just like a polar bear in the Sahara would struggle with the heat. We are smarter than the average bear and can, with the proper guidance, think our way through this.

I think you would benefit from meeting with a nutritionist as you suggest. But I strongly encourage you to make today the first day of eating well for the rest of your life rather than the start of another diet to go on and get back off. Learn to eat well, let your weight take care of itself, and never go on a diet again.

Member: What about someone who doesn't need to control his or her weight? Do I have to eat low fat too?

Katz: Recall I am not emphasizing a low-fat diet. Roughly 25% or so of calories from fat is ideal. However, this figure is not etched in stone, and provided the fats in the diet are health-promoting fats a bit more is fine. As is, for that matter, a bit less. Most important, however, is to recall that the way we eat profoundly influences overall health in countless ways. Whether thin or overweight, whether working to control your weigh or not, eating well matters for us all. So for you, as well as those who find weight control challenging, a prudent diet, moderate and balanced, rich in grains, vegetables, fruit, is vitally important to overall health.

Moderator: Thanks to David Katz, MD, for being our guest. For more information on a heart-healthy diet and lifestyle, read The Way to Eat: A Six-Step Path to Lifelong Weight Control, by David L. Katz, MD.

And explore the WebMD Weight Loss Clinic Community. Goodbye and good health!

Originally published Feb. 19, 2003.

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