When I opened my cardiology practice more than sixty years ago, the concept of dieting was simple: to stay fit, eat less. There was little thought as to whether what you ate might actually be promoting heart disease. Since then, I’ve watched diet fads come and go—and sometimes come back again.
In the 1970s the Scarsdale diet was all the rage. It had a simple premise: all one had to do to stay fit was eat one thousand calories or less, no matter one’s body size, gender, or level of activity. This one-size-fits-all plan quickly lost favor as consumers found that it was easier said than done.
The Pritikin diet defined thinking about weight loss in the 1980s. It advocated a low-fat, high-fiber diet. Its emphasis on limiting intake of red meat and processed food was a precursor to the vegetarian diets that would become popular two generations later. But devotees tired of its limited food choices and a feeling of constant hunger.
In the 1990s the Atkins diet became the first popular high-protein, high-fat, low-carb diet. The whole idea behind the diet was that excessive body fat was caused by consuming not only fatty foods but also foods consisting of carbohydrates and particularly simple carbs. Americans were by then no doubt consuming excessive amounts of food loaded with simple carbohydrates like sugary soft drinks, candy, cakes, and food products manufactured with fructose. But again, many consumers found that the diet often did not help them maintain weight loss over the long term. And the simple truth of the matter is that some simple carbohydrates, such as fresh fruits and vegetables, are good for you (although they still need to be monitored for total caloric intake).
A few years later the Zone diet captured the public’s attention. Like the Atkins diet, it emphasized high protein and low carbs, and fat intake was carefully monitored and controlled. Its signature directive was that followers had to eat five times a day in order to maintain their proper glycemic index. The diet fell out of favor as consumers found it difficult to stick to the multiple daily meals.
Remember the South Beach diet of the early 2000s? The foundational theory behind this diet was classifying carbohydrates as good or bad. It was the Zone diet but without the five-meal requirement and no calorie restriction. To its credit, distinguishing between simple and complex carbohydrates made sense.
And who can forget the Paleo “caveman” diet, based on the 1890s writing of Dr. John Harvey Kellogg, who posited that the primitive diet of humans, while they were still primarily hunter-gatherers, was superior to the diet that emerged after the advent of agriculture. (There’s no little irony here that Kellogg also invented the modern-day breakfast cereal. Yep, that Kellogg.) In 2013 the Paleo diet was the most popular among Google searches, as followers adhered to a diet of lean meats, fish, fruits, vegetables, nuts, and seeds and avoided all grains, potatoes, legumes, salt, sugar, dairy, and processed foods.
Now, in 2020, where are we when it comes to dieting? The cold harsh reality is that while all these diets worked for some people at least some of the time, for most people they did not. Two-thirds of Americans today are either overweight or obese, and childhood obesity has tripled in the past three decades.
Which brings me to my patient Nathan. A boyish-looking thirty-six-year-old, he nevertheless was definitely on the older end of the Millennial Generation. At five feet, ten inches tall and weighing 240 pounds, Nathan was definitely overweight, and in pursuit of a slimmer self, he had tried all the diets I just mentioned. No kidding.
“But Nathan, you weren’t even born when some of these diets were popular. How did you even find them?” I asked him.
“What can I say, Doc? I’m a great researcher. I even found some of the diet books in a box in my parents’ basement,” he said.
Nathan worked in video game development for a large company in Los Angeles’s “Silicon Beach”—the area formerly known as Playa Vista (just south of Marina del Rey) that has become the high-tech nexus for the city. A typical day for him was sitting in front of a computer screen doing whatever video game developers do. He rarely exercised. In fact, during the day he rarely moved. His sedentary lifestyle was exacerbated by his frat-boy diet, which consisted of mainly fast or frozen foods, and his blood panel revealed excessive amounts of sodium and dangerously high levels of LDL cholesterol. He was a prime candidate for silent heart disease.
“Maybe you should create a diet video game?” I mused.
“Funny, Doc. For some reason, I don’t think that would ever fly with the higher-ups,” he said.
“But seriously, to find the secret to a healthy diet, you have to go much further back than thirty, forty, or fifty years. We have to go back to ancient Greece,” I told him.
“Now you’ve got my attention.”
In fact, the notion of a diet harkens back to the ancient Greek word diata, which referred to a philosophy of self-control and eating in moderation. The Greeks and Romans understood that food and exercise influenced fitness and weight. The Christians later reinterpreted this self-control as asceticism, with a denial of worldly pleasures as the only true pathway to the elevation of the soul. Gluttony was one of the cardinal sins of thirteenth-century Christendom, right up there with greed, wrath, sloth, and lust.
Not until the 1940s would we have the first inkling of a connection between diet and heart health. As noted earlier in the book, medical scientists began to seriously look at heart disease as a national health epidemic when the number of deaths attributed to the condition in the United States in one year eclipsed the total number of Americans who died in combat or from combat-related accidents during all of World War II. Seemingly healthy, middle-aged men were dropping dead in the streets of America, and one area the scientists turned their gaze toward in search of clues was diet.
One early key piece of research in establishing the correlation between heart health and diet was the Seven Countries Study led by Ancel Keys, an American physiologist who specialized in researching the impact of diet on health. He launched the Seven Countries Study in 1958, after exploratory research on the relationship between dietary patterns and the prevalence of coronary heart disease in Greece, Italy, Spain, South Africa, Japan, and Finland.
There were two key findings: (1) high levels of cholesterol in blood serum were associated with a high risk of coronary heart disease mortality, and (2) a Mediterranean-style diet was consistently associated with lower cardiovascular risk by as much as 39 percent. Subsequent research, including the famed Framingham Heart Study in the United States a few years later, confirmed as much. However, for the next twenty years or so, we barely heard a peep about the Mediterranean diet, despite the seemingly convincing evidence of its efficacy in fighting coronary artery heart disease. For reasons that perhaps harken back to America’s Puritan beginnings, doctors and patients—even the American Heart Association (AHA)—alike became laser-focused on fat as bad, no matter that the Mediterranean diet rejected that myopic view. (There’s that venal sin of gluttony rearing its ugly head again.)
Not until 1977 did the AHA finally begin adopting recommendations that mimicked the Mediterranean diet with its publication of “Dietary Goals in the United States”—the first comprehensive statement by any branch of government on heart disease risk factors in the American diet. It advised that “too much fat, too much sugar or salt in a diet could be directly linked to heart disease, and stroke … and told Americans to eat more fruits, vegetables, whole grains, poultry, and fish.”
Just a few years later, AHA changed gears again and returned to an emphasis on controlling dietary fat in a consensus report titled “Lowering Blood Cholesterol to Prevent Heart Disease,” which was endorsed by the American Medical Association and the National Heart, Lung, and Blood Institute. Although some scientists and physicians remained unconvinced by the data, nevertheless, the low-fat contingency won the day, and the Mediterranean diet once again fell into obscurity.
“So, Nathan, you’ve become somewhat of a diet expert. Have you heard of the Mediterranean diet?”
“Um, is that what they eat in Italy? I love lasagna, by the way.”
The Mediterranean diet really isn’t just one diet but rather an umbrella term for many culinary traditions of the countries that border the Mediterranean Sea. To Nathan’s point, yes, Italian food falls under the umbrella, but so do the diverse cuisines of Spain, Turkey, Israel, Morocco, and Lebanon. Despite their flavorful difference, they share a common foundation. Their dishes are typically low in red meat, sugar, and saturated fats and high in fresh vegetables, fruit, seafood, nuts, legumes, and whole grains.
While France is on the Mediterranean Sea, the primary fat in its sophisticated cuisine is animal-based, mainly butter and cream. On the other hand, the fat primarily used in the Mediterranean diet is olive oil. In fact, the countries of the Mediterranean diet are sometimes referred to as the olive-growing region of the world. The foods in this region are nutrient rich and are packed with minerals, protein, whole grains, and other nutrients but are lower in calories than the typical American diet. Seasoning leans toward spices rather than salt.
There isn’t an emphasis on less fat per se but rather on nutrientdense whole foods. Indeed, some foods that are “fatty” are essential to a Mediterranean diet. Olive oil supplies monounsaturated fatty acid, and the fish, nuts, and whole grains supply omega-3 and omega-6 fatty acids. Thus, there is ample supply of the essential fatty acids. That said, in the Mediterranean diet, fat makes up only about 30 percent of total calories. The consumption of meat and dairy products high in saturated fats is minimal, and the overall intake of saturated fat is low, typically less than 10 percent of total calories.
Related to the Mediterranean diet is the Dietary Approaches to Stop Hypertension (DASH) diet, which mimics the same kinds of foods but also places special emphasis on reducing salt. Followers begin capping sodium at twenty-three hundred milligrams a day, eventually lowering their daily intake to about fifteen hundred milligrams.
Now, we come full circle. As I write, a new study was released in August 2019 confirming the original findings of the Seven Countries Study. Released by none other than the American Heart Association, the study concludes that eating mostly plant-based foods and fewer animal-based foods may be linked to better heart health and a lower risk of dying from a heart attack, stroke, or other cardiovascular disease.
Lead researcher Casey M. Rebholz, PhD, assistant professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health, in Baltimore, Maryland, and her team reviewed a database of food intake information from more than ten thousand middle-aged U.S. adults who were monitored from 1987 through 2016 and did not have cardiovascular disease at the start of the study. They then categorized the participants’ eating patterns by the proportion of plant-based foods they ate versus animal-based foods.
People who ate the most plant-based foods overall had the following:
•16 percent lower risk of having a cardiovascular disease such as heart attack, stroke, heart failure, and other conditions
•32 percent lower risk of dying from a cardiovascular disease
•25 percent lower risk of dying from any cause compared to those who ate the least amount of plant-based foods
“Our findings underscore [that] … to reduce cardiovascular disease risk people should eat more vegetables, nuts, whole grains, fruits, legumes and fewer animal-based foods. These findings are pretty consistent with previous findings about other dietary patterns, including the DASH diet, which emphasize the same food items,” Rebholz said. And I might add, the Mediterranean diet.
I would be remiss in our discussion of heart-healthy diets if I didn’t discuss vegetarianism. Like the Mediterranean diet, it takes many forms. Some vegetarians eat no animal protein (vegans), others eat dairy products (lacto-ovo vegetarians), and still others eat fish (pescatarians). It might be better to think of these diets as “pro-vegetarian” because they all emphasize to varying degrees a diet based on fresh fruits and vegetables, nuts, whole grains, and legumes—like the Mediterranean diet.
The benefits of a pro-vegetarian diet were confirmed in a study whose findings were published in April 2019 in the Journal of the American College of Cardiology. Dr. Kyla Lara, a cardiology fellow at the Mayo Clinic in Rochester, Minnesota, and her colleagues examined the associations between five major dietary patterns and the risk of heart failure among people without any known history of heart disease. Namely, they looked at the dietary patterns among 16,068 black and white people who were forty-five years old, on average. The participants answered a 150-item survey, which included 107 food items. The researchers grouped the foods into dietary patterns:
•“Convenience” diets, which consisted of meat-heavy dishes, pasta, pizza, and fast food
•“Plant-based” diets, consisting mainly of vegetables, fruit, beans, and fish
•“Southern” diets, which comprised a significant amount of fried foods, processed meat, eggs, added fats, and sugary drinks
•“Alcohol/salad” diets, which included lots of wine, liquor, beer, leafy greens, and salad dressing
Lara and her team followed the participants for 8.7 years on average. Overall, the researchers found that adhering to the southern diet increased the risk of hospitalization due to heart failure by 72 percent, while sticking to a diet rich in fruits, vegetables, and fish can slash heart failure risk by 40 percent.
A similar finding by another study was essentially that you don’t have to eat strictly vegetarian to reap the benefits of a Mediterranean-style diet. A team from Erasmus University Medical Center, based in Rotterdam, the Netherlands, examined long-term health information collected as part of the Rotterdam study. The data included 9,641 adults with an average age of sixty-two years who took part in this ongoing population-based study. In particular, the researchers were interested in the participants’ diet, body mass index (BMI), waist circumference, weight in relation to height (fat mass index), and body fat percentage.
The participants received points for eating nuts, fruits, and vegetables and lost points for eating meat, dairy, and fish. So the higher individuals’ scores, the more closely they adhered to a plant-based diet. The team found that people with the highest scores on the index were more likely to have a lower BMI over the long term.
Lead study author Zhangling Chen concluded, “Eating a plant-based diet to protect against obesity does not require a radical change in diet or a total elimination of meat or animal products. Instead, it can be achieved in various ways, such as moderate reduction of red meat consumption or eating a few more vegetables. This supports current recommendations to shift to diets rich in plant foods with low consumption of animal foods.”
“Wow. So, switching to a plant-based diet will turn my health around, eh, Doc? You know, I just got turned on to cauliflower cheese pizza. And french fries are vegetarian, too, right?” said Nathan.
“Now, hold on. The fact that we’re reducing the animal protein in your diet isn’t a license for you to binge on other kinds of bad food. There’s very little nutritional value in either cauliflower cheese pizza or French fries, and they’re probably loaded with salt,” I said.
“You mean I’ll be chained to broccoli and arugula for the rest of my life?”
“Not exclusively, but they will be part of your new Mediterranean diet, filled with fresh fruits and vegetables and low in salt, sugar, and processed foods, including sugary soft drinks and those packaged baked goods containing trans fats. Your days of fast and frozen food are gone. Instead, you’re eating fresh fish at least twice a week, especially fish high in omega-3 fatty acids like tuna and salmon. If you choose to eat meat, look for the leanest cuts available and prepare them in healthy and delicious ways. And you’ll select fiber-rich whole grains for most grain servings.”
I continued, “You said you like Italian food, right? How about Spanish, Turkish, or Lebanese? If you are not familiar with these cuisines, well, Nathan, you’re about to experience a whole new world of food.”
“Hmmm. The Mediterranean diet video game. An army of fruits, nuts, and legumes combats the dark forces of red meat, sugar, and salt. Throw in some wizards and ogres, and we might have a hit, Doc!”
“And don’t forget the brass ring is improved cardiovascular health,” I chimed in.
“Yeah, I’ll get the marketing team to work on that last part.”
(There are scores of cookbooks for the Mediterranean diet available online or at your local bookstore. For a list of foods and suggested meals on the Mediterranean diet that I recommended for Nathan, visit the Eating Well website at http://www.eatingwell.com/article/291946/30-day-mediterranean-diet-meal-plan-1200-calories.)