Tag Archives: China Study

What Is A Plant-Based Diet (And Should I Be On One)?

The phrase “plant-based diet” is being tossed around a lot these days. The skeptical cardiologist never knows what people mean when they use it and so must assume that most of the world is also puzzled by this trendy term.

Is A Plant-Based Diet Code For Veganism?

For some, a “plant-based diet” (PBD) is what vegans eat.

Veganism combines a diet free of animal products, plus a moral philosophy that reject the “commodity status of animals.” Vegans are the strictest of vegetarians, eschewing milk, fish and eggs.

One PBD advocate in the introduction to a Special Issue of the Journal of Geriatric Cardiology,  defines it as follows:

“a plant-based diet consists of all minimally processed fruits, vegetables, whole grains, legumes, nuts and seeds, herbs, and spices and excludes all animal products, including red meat, poultry, fish, eggs, and dairy products.”

You will notice that this cardiologist “excludes all animal products”  and that the qualifying phrase “minimally processed” has crept into the definition.

Forks Over Knives-Whole-food, plant-based diet

The “documentary” Forks Over Knives brought the phrase “whole food, plant-based diet” to national prominence. The movie focused on the diets espoused by Caldwell Esselstyn and T. Colin Campbell. Since its release in 2011 a whole industry based on the Forks Over Knives (FON) brand has been launched. FON uses the following definition:

 “A whole-food, plant-based diet is centered on whole, unrefined, or minimally refined plants. It’s a diet based on fruits, vegetables, tubers, whole grains, and legumes; and it excludes or minimizes meat (including chicken and fish), dairy products, and eggs, as well as highly refined foods like bleached flour, refined sugar, and oil.”

I’ve written detailed posts on the Esselstyn diet here and here. I think it is needlessly restrictive and not supported by scientific evidence. (Esselstyn’s website and book state unequivocally “you may not eat anything with a mother or a face (no meat, poultry, or fish” and “you cannot eat dairy products” which differs from the FON definition.)

The key new terms in the FON approach to note are:

Whole Food. The Oxford English Dictionary (OED) defines whole food as “food  that has been processed or refined as little as possible and is free from additives or other artificial substances.”

Unrefined or minimally refined. The OED defines refined as:

“With impurities or unwanted elements having been removed by processing.”

The FON definition for a PBD then is similar to our first definition-minimally processed vegan-but allows (at least theoretically)  minimal meat, dairy and eggs. The FON Esselstyn/Campbell diets choose to define vegetable oil, including olive oil, as highly refined foods and do not allow any oils.

U.S. News and World Report Definition Of Plant-Based Diets

U.S. News and World Report publishes an annual rating of diets based on the opinion of a panel of nationally recognized experts in diet, nutrition, obesity, food psychology, diabetes and heart disease.

US News defines a plant-based diet as “an approach that emphasizes minimally processed foods from plants, with modest amounts of fish, lean meat and low-fat dairy, and red meat only sparingly.”

This definition is radically different from the first two. Notice now that you can have “modest amounts” of meat and dairy, foods which are anathema to vegans. Also, note that “low-fat dairy” is being recommended, a food which (in my opinion) is highly processed and that lean meat is to be preferred and red meat avoided.

I was happy to see that for the first time, the Mediterranean Diet ranked as  Best Diet Overall, but shocked to find that the Mediterranean diet came out on top of the US News list of “Best Plant-Based Diets.”

Readers will recognize that this is the diet I recommend and follow (with slight modifications). On this diet I regularly consume hamburgers, steak, fish and whole egg omelettes.

The plant-based diet of vegans or of Forks Over Knives is drastically different from the Mediterranean Diet.

For example, olive oil consumption is emphasized in the Mediterranean Diet, whereas the Esselstyn diet featured in FON forbids any oil consumption.

The FON/Esselstyn diets are very low in any fats, typically <10%, whereas the Mediterranean Diet is typically 30-35% fat.

Esselstyn really doesn’t want you to eat nuts and avocados because he thinks the oil in them is bad for you. This is nuts! I’m handing out nuts to my patients just as they were given to the participants in the PREDIMED randomized trial showing the benefits of the Med diet.

Dr. Pearson’s Plant-Based Diet

Since the term “plant-based diet” apparently means whatever a writer would like it to mean, I have come up with my own definition.

With the  Dr. P Plant-Based Diet© your primary focus in meal planning is to make sure that you are regularly consuming a large and diverse amount of healthy foods that come from plants.

If you don’t make it your focus, it is too easy to succumb to all the cookies, donuts, pies, cakes, pretzels, chips, French fries,  breakfast bars and other  calorie-dense but nutrient-light products that are cheap and readily available.

In Dr. P’s Plant-Based Diet© meat, eggs, and full fat dairy are on the table. They are consumed in moderation and they don’t come from plants (i.e. factory farms).

I, like the PBD  definers of yore, have taken the liberty of including many vague terms in my definition. Let me see if I can be more precise:

Regularly = at least daily.

Large amount = 3 to 4 servings daily.

Healthy = a highly contentious term and one, like “plant-based” that one can twist to mean whatever one likes. My take on “healthy” can be seen on this blog. I’m not a fan of plant-based margarines, added sugar, whether from a plant or not, should be avoided, and the best way to avoid added sugar is to avoid ultra-processed foods.

Ultra-processed foods (formulations of several ingredients which, besides salt, sugar, oils and fats, include food substances not used in culinary preparations, in particular, flavours, colours, sweeteners, emulsifiers and other additives used to imitate sensorial qualities of unprocessed or minimally processed foods and their culinary preparations or to disguise undesirable qualities of the final product).

Ultra-processed foods account for 58% of all calories in the US diet, and contribute nearly 90% of all added sugars.

I do like the food writer Michael Pollan’s simple rules to “Eat Food. Mostly Plants. Not Too Much.” and this NY Times piece summarizes much of what is in his short, funny and helpful Food Rules book:

you’re much better off eating whole fresh foods than processed food products. That’s what I mean by the recommendation to eat “food.” Once, food was all you could eat, but today there are lots of other edible foodlike substances in the supermarket. These novel products of food science often come in packages festooned with health claims, which brings me to a related rule of thumb: if you’re concerned about your health, you should probably avoid food products that make health claims. Why? Because a health claim on a food product is a good indication that it’s not really food, and food is what you want to eat.

On Dr. P’s Plant-Based Diet© you can add butter to your leeks and green onions.You can add eggs to your onions, tomatoes and peppersAnd you can eat salads full of lots of cool different plants for lunch.

To answer my titular question-if you are using Dr. P’s definition of a plant-based diet then you definitely should be on one.

Viva La Plant!

-ACP

Which Popular Diets Are Supported By Science?

Which of the currently popular and highly marketed diets are best for weight loss and cardiovascular health? Can science answer this question?
questI just took a 90 minute online “course” taught by Eric Rimm of the Harvard School of Public Health; I think he does a good job of summarizing the scientific evidence on this topic and presenting it in a way that the average layperson can understand.

You can sign up for free here. If you’re not interested in spending your time watching him, here are my take-home points:

1. When evaluating the efficacy of a diet to control weight, the best evidence comes from observational studies that involve tens of thousands patients over decades and/or (preferably) randomized control trials that last at least two years.

2. The Paleo, Wheat-belly, gluten-free, Atkins, South Beach, and Zone diets do not have good evidence supporting sustained weight loss or health benefits. In general, people who follow these diets will be consuming lots of fresh vegetables, nuts and “healthy” fats and avoiding processed food, which is good, and this likely explains any  benefits achieved.

3. Of all the diets, the low-fat diet (Ornish/Pritikin/China Study are the extreme examples of this) is the only one which has strong evidence showing an absence of benefit.

Yes, the diet that was recommended to Americans for 30 years does not help with weight loss in the long run for the vast majority of individuals.

As Rimm says “We need to eliminate the dogma that low fat is needed for weight loss.”

Dr. Rimm spends a good amount of time on this, highlighting findings from a study of 50 thousand women (the Women’s Health Initiative), which lasted for 9 years. In the first year, women on the low-fat diet (counseled to consume <20% of calories in the form of fat), lost more weight than those on the usual diet, however, in subsequent years they gained back the weight and did not differ from the higher fat consuming group.

There was also no difference in the rates of dying or contracting any disease between the two groups.

The problem with the low fat diet was adherence. Although a very small percentage of individuals can remain on a  vegan or really low-fat diet and successfully lose weight and be healthy, the majority of us can’t.

By the end of the study the low fat group had increased their fat consumption to 28% which was not much less than what the usual group was consuming (32%)

Over time, the low fat group gradually added fats because they taste better and they are more satiating.

4. The DASH diet has evidence showing improvement in blood pressure, and cholesterol. The heart of the DASH diet is an eating plan rich in fruits and vegetables, low-fat and nonfat dairy, along with nuts, beans, and seeds.

Unfortunately, it was developed in an era when all fats were considered bad and proof of cardiovascular benefit is lacking.

5. Mediterranean diet. Gets a strong pass from Rimm with multiple studies showing benefits in both weight reduction and reduction of cardiovascular mortality.

The Med diet also demonstrates good long term adherence because of its diversity and inclusion of fat (for taste and satiety).

Improved adherence has been shown to be the major determinant of diet success. When you add regular counseling and support to any diet it works better and can be sustained.

This is the Mediterranean diet I recommend:

1. Lots of fresh fruits and vegetables. These contain fiber, phytochemicals, minerals.

2. Two servings of fish per week.

3. Plenty of nuts (and drupes!), legumes, and seeds.

4. Grains are allowed, preferably all whole grains.

5. Moderate alcohol consumption (1 drink/day for women, 2 drinks/day for men).

6. Olive oil.

7. Meat is allowed.

8. Eggs and dairy are allowed.

Dr. Rimm is still clinging to the idea that all saturated fats should be limited and preferfat replacementably replaced by PUFAs or MUFAs. He presented this graphic (courtesy of Dr. Willet at Harvard), which illustrates the most prevalent concepts about saturated fat replacement.

Risk of heart disease is on the y axis. According to this graph, If you replace saturated fat with trans fat or sugar/refined starch, risk goes up.

If you replaced saturated fat with unsaturated vegetable fats or whole grains, risks go down.

Most nutritional experts now can agree on the importance of the key components of the Med diet and the lack of efficacy of low fat diets.

The disagreement comes in whether moving that arrow down from saturated fat to unsaturated fat is truly beneficial for weight management or cardiovascular health.

Good Fats and Bad Fats?

My own take on the good fat/bad fat controversy is as follows:

There are multiple types of saturated fats and multiple types of unsaturated fats and the scientific evidence is not currently robust enough to make the claim that replacing any saturated fat  with any unsaturated fat is a healthy change.

There is no evidence that low-fat or no fat dairy is healthier than full fat dairy (see here and here). Eating no, or low, fat yogurt with the natural fat replaced by sugar and other additives likely moves the arrow up, raising your risk. This kind of processed food gets a pass from mainstream nutritionists for some reason.

Saturated fat from pasture-raised pigs and cows consumed in moderation is not unhealthy or weight gain promoting.

In the end, Dr. Rimm and I agree on about 95% of the science and recommendations in his course.

Take a look and you can tell your friends that you just passed a Harvard course with flying colors!