Excerpt from Dr. Greger's seminal book, How Not to Die:

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​Eating is essentially a zero-sum game: When you choose to eat one thing, you are generally choosing not to eat another.  Sure, you could just go hungry, but eventually your body tends to balance things out by eating more later. So anything we choose to eat has an opportunity cost.

 

Every time you put something in your mouth, it’s a lost opportunity to put something even healthier in there.  Think of it as having $2000 in your daily caloric bank. How do you want to spend it? For the same number of calories, you can eat one Big Mac, one hundred strawberries, or a five-gallon bucket of salad.

 

Isn’t It Expensive to Eat Healthfully?

 

Researchers at Harvard University compared the cost and healthfulness of various foods across the country, hunting for the best bargains.  They concluded: “The purchase of plant-based foods may offer the best investment for dietary health.”

 

So on a cost-per-nutrition basis, vegetables offer six times more nutrition per dollar compared to highly processed foods.  Meat costs about three times more than vegetables yet yields sixteen times less nutrition based on an aggregate of nutrients.  Because meat is less nutritious and costs more, vegetables net you forty-eight times more nutrition per dollar than meat.

 

Spending just fifty cents more per day on fruits and vegetables may buy you a 10 percent drop in mortality.

 

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Dining by Traffic Light

 

Just as on the road, green means go, yellow means caution, and red means stop.  (In this case, stop and think before you put it into your mouth.)  Ideally, green-light foods should be maximized, yellow-light ones minimized, and red-light foods avoided.

 

The healthiest diet is one that maximizes the intake of whole plant foods and minimizes the intake of animal-based foods and processed junk.  Simply put, eat more green-light foods. Eat fewer yellow-light foods. And, especially, eat even fewer red-light foods.

 

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Why Don’t the Dietary Guidelines Just Say No?

 

The green-light message shines brightly in pronouncements telling you to “eat more fruits and vegetables,” but the yellow and red lights can be dim and cloudy thanks to politics.  In other words, the guidelines are clear when there is eat-more messaging (“Eat more fresh produce”), but eat-less messaging is obscured into biochemical components (“Eat less saturated and trans fatty acids”).  National health authorities rarely just say to “eat less meat and dairy.” That’s why my green-light message will sound familiar to you (“Oh, ‘eat fruits and veggies’--I’ve heard that before”) but the yellow- and red-light messages may sound controversial (“What?  Minimize meat? Really?”).

 

Part of the USDA’s mission is “expanding markets for agricultural products.”  At the same time, the federal agency is tasked with protecting public health by helping to develop the Dietary Guidelines for Americans.  That’s why, when those two directives are in-sync, their eat-more language is clear: “Increase fruit intake.” “Increase vegetable intake.” But when their dual mandates are in conflict--when “Improving nutrition and health” is at odds with promoting “agriculture production”--the eat-less messaging of the Dietary Guidelines gets repackaged and ends up referring to biochemical components: “Reduce intake of solid fats (major sources of saturated and trans fatty acids).”

 

When the Guidelines tell you to eat less added sugar, calories, cholesterol, saturated fat, sodium, and trans fat, that’s code for eat less junk food, less meat, less dairy, fewer eggs, and fewer processed foods.  But they can’t actually say that. When they did in the past, all heck broke loose. For example, when a USDA employee newsletter even suggested trying a meat-free lunch once a week as part of Johns Hopkins University’s School of Public Health “Meatless Mondays” initiative, the resulting political firestorm from the meat industry led the USDA to retract the advice just hours later.  “As a result of these conflicts [of interest],” concluded an analysis in the Food and Drug Law Journal, “the Guidelines sometimes favor the interests of the food and drug industries over the public’s interest in accurate and impartial dietary advice.”

 

The landmark report on trans fat from the National Academy of Sciences’ Institute of Medicine concluded that no amount of trans fat is safe “because any incremental increase in trans fatty acid intake increases C[oronary] H[eart] D[isease] risk.”

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How SAD Is the Standard American Diet?

 

In a 2010 report from the National Cancer Institute on the status of the American diet found that three out of four Americans don’t eat a single piece of fruit in a given day, and nearly nine out of ten don’t reach the minimum recommended daily intake of vegetables.  On a weekly basis, 96 percent of Americans don’t reach the minimum for greens or beans (three servings a week for adults), 98 percent don’t reach the minimum for orange vegetables (two servings a week), and 99 percent don’t reach the minimum for whole grains (about three to four ounces a day).

 

“In conclusion,” the researchers wrote, “nearly the entire U.S. population consumes a diet that is not on par with recommendations.  These findings add another piece to the rather disturbing picture that is emerging of a nation’s diet in crisis.”

 

How I Define “Processed”

 

My Traffic Light model stresses two important general concepts: Plant foods, with their greater protective nutritional factors and fewer disease-promoting ones, are healthier than animal foods, and unprocessed foods are healthier than animal foods, and unprocessed foods are healthier than processed foods.  Is that always true? No. In fact, one of the worst items on store shelves is partially hydrogenated vegetable shortening--a product that has vegetable right in its name! Even some unprocessed plants--such as blue-green algae--can be toxic. Anyone who’s had a bad case of poison ivy knows plants don’t always like to be messed with.  In general, though, choose plant foods over animal foods, and unprocessed over processed.

 

“If it came from a plant, eat it.  If it was made in a plant, don’t.” ~ MIchael Pollan

 

What do I mean by processed?  The classic example is the milling of grains from whole wheat to white flour.  Isn’t it it ironic that these are called “refined” grains, a word meaning improved or made more elegant?  The elegance was not felt by the millions who died in the nineteenth century from beriberi, a vitamin B-deficiency disease that resulted from polishing rice from brown to white. A Nobel Prize was awarded for the discovery of the cause of beriberi and its cure--rice bran, the brown part of rice that was removed.  Beriberi can cause damage to the heart muscle, resulting in death from heart failure. Surely such a thing could never happen in modern times--an epidemic of heart disease that could be prevented and cured with a change in diet? Com on. (Please reread chapter 1.)

 

Sometimes, however, processing can make foods healthier.  For example, tomato juice appears to be the one common juice that may actually be healthier than the whole fruit.  The processing of tomato products boosts the availability of the antioxidant red pigment lycopene by as much as fivefold.  Similarly, the removal of fat from cacao beans to make cocoa powder improves the nutritional profile, because cocoa butter is one of the rare saturated plant fats (along with coconut and palm kernel oils) that can raise your cholesterol.

 

So for the purposes of the Traffic Light model, I like to think of “unprocessed” as nothing bad added, nothing good taken away.  In the above example, tomato juice could be thought of as relatively unprocessed because even much of the fiber is retained--unless salt is added, which would make it a processed food in my book and bump it right out of the green zone.  Similarly, I would consider chocolate--but not cocoa powder--processed because sugar is added.

 

Using my definition of nothing bad added, nothing good taken away, steel-cut oats, rolled oats, and even (plain) instant oatmeal can all be considered unprocessed.  Almonds are obviously a whole plant food. I would also consider no-salt-added almond butter to be a green-light food, but even unsweetened almond milk is a processed food, a food from which nutrition has been stolen.  Am I saying almond milk is bad for you? Foods are not so much good or bad as they are better or worse. All I’m saying is that unprocessed foods tend to be healthier than processed ones. Think of it this way: eating almonds is healthier than drinking almond milk.

 

The limited role I see for yellow-light foods in a healthy diet is to promote the consumption of green-light foods.  For instance, if the only way I can get patients to eat oatmeal in the morning is if they make it creamy with almond milk, then I tell them to go right ahead. The same could be said for red-light foods. Without hot sauce, my intake of dark-green, leafy vegetables would plummet. Yes, I know there are all sorts of sodium-free, exotically flavored vinegar's out there that I could use, and maybe one day I’ll wean myself off Tabasco.  But given my current tastes, the green ends justify the red means.

 

What Does “Whole-Food, Plant-Based” Mean, Exactly?

 

From a nutrition standpoint, the reason I don’t like the terms vegetarian and vegan is that they are only defined by what you don’t eat. When I used to speak on college campuses, I would meet vegans who appeared to be living off french fries and beer.  Vegan, technically, but not exactly health promoting. That’s why I prefer the term whole-food, plant-based nutrition.  As far as I can discern, the best available balance of evidence suggests that the healthiest diet is one centered on unprocessed plant foods.  On a day-to-day basis, the more whole plant foods and the fewer processed and animal products, the better.

 

Preparing Yourself for Healthier Habits

 

First, you need to know your own psychology.  There are certain personality types that do better when they go all in.  If you tend to have an “addictive” personality, or if you are the kind of person who takes things to extremes--for instance, you either don’t drink at all or you drink in excess--it’s probably best for you to try to stick with the program.  

 

There’s a concept in psychology called “decision fatigue” that marketers use to exploit consumers.  It appears humans have a limited capacity to make many decisions in one short stretch of time, and the quality of our decisions will deteriorate to the extent that we eventually begin making downright irrational choices.

 

So making rules for yourself and sticking to them may help you make more sensible choices over the long run.  For instance, making a strict decision to never cook with oil, to avoid meat entirely, or to eat only whole grains may paradoxically make for sturdier life changes.  By not having junk food in the house, you remove the temptation by removing the choice. I know if I get hungry enough I’ll eat an apple.

 

There may also be a physiological argument for not widely deviating from a well-planned diet.  After a vacation cruise during which you indulged in all manner of rich foods, your palate may get dulled to the point where the natural foods you enjoyed just the week before no longer deliver the same taste satisfaction.  For some, this may simply require a period of readjustment. But for others, this departure from an otherwise healthy diet may lead back to a dietary glut involving added salt, sugar, and fat.

 

For those of us who grew up eating SAD (the Standard American Diet), starting to eat healthfully can be a big shift.

Some go cold turkey, if you will, while others transition more slowly using a variety of approaches.  One I’ve used personally in my medical practice is Kaiser Permanente’s three-step method. Realizing that most American families tend to rotate through the same

eight or nine meals, step one suggests that you think of three meals you already enjoy that are plant based, like pasta and marinara sauce that could be easily tweaked to whole-grain pasta with some added veggies.  Step two asks you to think of three meals you already eat that could be adapted to become a green-light meal, like switching from beef chili to five-bean chili.  Step three is my favorite: Discover new healthy options.