Putting the Daily Dozen to the Test

Whenever I’m asked at a lecture whether some food is healthy or not, my reply is: “Compared to what?” For example, are eggs healthy? Compared to some breakfast sausage next to it? Yes, but compared to oatmeal? Not even close. Think of it as having $2,000 in your daily calorie bank. How do you want to spend it? For the same number of calories, you can eat one Big Mac, 50 strawberries, or a half a wheelbarrow-full of salad greens. Now, they don’t exactly fill the same culinary niche—I mean, if you want a burger, you want a burger—and I don’t expect quarts of strawberries to make it onto the Dollar Menu anytime soon. But, it’s an illustration of how mountainous a nutrition bang you can get for the same caloric buck.

Every time we put something in our mouth, it’s a lost opportunity to put something even healthier in our mouth. So, what are the best foods to eat and the best foods to avoid? Here’s how I like to think of it.

This is my traffic light system to help quickly identify some of the healthiest options. Green means go, yellow means caution, and red means stop (and think before you put it into your mouth).

Ideally, on a day-to-day basis, green category foods should be maximized, yellow foods minimized, and red category foods avoided. As far as I can figure, the best available balance of evidence suggests the healthiest diet is one that maximizes the intake of fruits, vegetables, legumes (which are beans, split peas, chickpeas, and lentils), whole grains, nuts and seeds, mushrooms, herbs, and spices. Basically, real food that grows out of the ground—these are our healthiest choices. In general, the more whole plant foods and the fewer processed and animal foods, the better. So, more green light foods and less yellow and red. Like running red lights in the real world: you may be able to get away with it once in a while, but I wouldn’t recommend making a habit out of it.

My traffic light model stresses two important concepts: Plant foods tend to be healthier than animal foods (in terms of being packed with protective nutrients and fewer disease-promoting factors), and unprocessed foods tend to be healthier than processed foods. Is that always true? No. Am I saying that all plant foods are better than all animal foods? No. In fact, the worst thing on store shelves has been partially hydrogenated vegetable shortening—it’s even got vegetable right in the name! Even some unprocessed plants—such as blue-green algae—can be toxic. Anyone who’s ever 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.

What do I mean by processed? The classic example is the milling of grains from whole wheat—for example, to white flour. Isn’t it ironic that these are then called “refined” grains, a word that means improved, or made more elegant? The elegance was not felt by the millions who died from beriberi in the 19th century, a vitamin B-deficiency disease that resulted from polishing rice from brown to white. White rice is now enriched with vitamins to compensate for the “refinement.” A Nobel Prize was awarded for the discovery of the cause of beriberi and its cure—rice bran, the brown part of rice. Beriberi can cause damage to the heart muscle, resulting in sudden death from heart failure. Surely, such a thing could never happen in modern times. I mean, an epidemic of heart disease that could be prevented and cured with a change in diet?

Sometimes, though, processing can make foods healthier. For example, tomato 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 by as much as five-fold. Similarly, the removal of fat from cacao beans to make cocoa powder improves the nutritional profile, since cocoa butter is one of the rare saturated plant fats (along with coconut and palm kernel oils) that may raise cholesterol.

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

The limited role I see for yellow-light foods in a healthy diet is to promote the consumption of green-light foods. They can be the spoonful of sugar that makes the medicine go down. So, if the only way I can get a patient to eat oatmeal in the morning is to make it creamy with almond milk, then tell them to add almond milk. The same could be said for red-light foods. If the only way you’re going to eat a big salad is to sprinkle it with Bac-Os, then sprinkle away.

Bac-Os are what are referred to ultra-processed foods—bearing no redeeming nutritional qualities or resemblance to anything that grew out of the ground, and often with added badness. Bac-Os, for example, have added trans fats, salt, sugar, and even Red #40, a food dye that may cause thousands of thyroid cancers every year. As a red light food, it should ideally be avoided, but if the alternative to your big spinach salad with Bac-Os is KFC, then it’s better to sprinkle. The same goes for real bacon bits.

I realize some people have religious or ethical objections to even trivial amounts of animal products. (Growing up Jewish next to the largest pig factory west of the Mississippi, I can relate to both sentiments.) But from a human health standpoint, when it comes to animal products and processed foods, it’s the overall diet that matters. For example, without hot sauce, my intake of dark green leafy vegetables would plummet. Yeah, I could try making my own from scratch, but for the time being, the green ends justify the red means.

On the same note, it’s really the day-to-day stuff that matters most. It really shouldn’t matter what we eat on special occasions. Feel free to put edible bacon-flavored candles on your birthday cake (I’m not actually making those up). Though I guess from a food-safety point of view, a raw cake-batter Salmonella infection could leave you in dire straits. In general, it’s really your regular routine that determines your long-term health. Our body has a remarkable ability to recover from sporadic insults, as long as we’re not habitually poking it with a fork.

That’s why, from a medical standpoint, I don’t like the terms vegetarian and vegan, because they are only defined by what you don’t eat. When I taught at Cornell, I had vegan students who appeared to be living off of French fries and beer. Vegan, perhaps, but not terribly health-promoting. That’s why I prefer the term whole food plant-based nutrition. In general, the dividing line between health-promoting and disease-promoting foods may be less plant- versus animal-sourced foods, and more whole plant foods versus most everything else.

In How Not to Die, I compiled the healthiest of the so-called Green Light foods into my Daily Dozen checklist and encouraged people to try to fit them into their daily routine. I made it into a free app, Dr. Greger’s Daily Dozen, available for iPhone and Android, so anyone and everyone can try to check off all the boxes every day and track their progress over time.

As the feedback poured in from millions of people giving the app a try, two themes of complaints arose. The first was that it was just too much food. There was no way they could eat all that food in one day. In response, I explained that the Daily Dozen was aspirational, something to shoot for, just a tool to inspire people to include some of the healthiest of healthy foods into their daily diets. The vast volume of food I prescribed was on purpose. I was hoping that by encouraging people to eat so much healthy stuff, it would naturally crowd out some of the less-healthy stuff. After checking off twenty-four servings in the Daily Dozen, there’s only so much room left for a pepperoni pizza.

Ironically, the second major complaint we got is that it doesn’t have enough calories. I had to explain that the Daily Dozen just represented the minimum I encourage people to eat, not the maximum, and that, certainly, training athletes requiring thousands more calories would have to eat much more. This all got me thinking, though. Too much food but too few calories? Sounds like the perfect weight-loss diet!

The Daily Dozen is by definition all Green Light foods, all whole plant foods; so, that right there bakes in all 17 ingredients of the ideal weight-loss diet I introduced in my book How Not to Diet. What about the calorie count? A systematic review of successful weight-loss strategies concluded that given the metabolic slowing and increased appetite that accompanies weight loss, to achieve significant weight loss, calorie counts may need to drop as low as 1,200 calories a day for women, and 1,500 calories a day for men. And what do you know? Plug in common foods into each of the categories, and the Daily Dozen averages about 1,200 calories, with the higher-calorie food choices nailing 1,500 calories.

In the second half of How Not to Diet, I focus on things that can further accelerate the loss of body fat, regardless of what you eat, which I encapsulated in my 21 Tweaks. My free Dr. Greger’s Daily Dozen app had become so popular at that point that I decided to revamp it with these new features. Now, if you switch over to the weight-loss setting, you can make a game out of how many fat-busting boosters you can squeeze in every day, along with your Daily Dozen checkboxes. Does this actually help people lose weight, though? You don’t know until you put it to the test.

As part of a master’s thesis in lifestyle medicine at the Lithuanian University of Health Sciences, a graduate student conducted: “Weight control and lifestyle change using Dr. Michael Greger’s Daily Dozen and 21 Tweaks: does it really work? A pilot study.” How cool is that? It’s a before-and-after study with no controls, so it’s really more like a case series of four men and four women, on average obese, who were encouraged to use the app and follow the Daily Dozen and 21 Tweaks for four weeks, preceded by a prep phase, which included education sessions and even a cooking class, then followed up for a month after the diet.

At the end of the four-week intervention, an average weight loss of about 15 pounds (6.80 kg) was achieved, along with a few inches dropped from the waist. The two folks with diabetes lowered their sugars by about 50 points. LDL cholesterol dropped by 35 points. That’s the kind of drop we’d see with a first-generation statin. Three reached their ideal range, under an LDL of 70. That’s really the most important thing, as heart disease is the leading killer in Lithuania, as it is in the United States. And in addition to physical health, mental health appears to improve as well.

A month after the study was over, the participants appeared to be able to retain enough healthy eating habits to maintain the weight loss and improved well-being. But as they strayed, their cholesterol and blood sugars crept back up. It was so cool to read all the participants’ comments. They never felt hungry, their taste buds started changing, and they even learned to cook a little oatmeal. Of course, what they were really happy about was losing all that weight while experiencing some positive side effects. Now obviously a small, uncontrolled study is some super-weak sauce evidence, but what it did show is that it’s possible to make a lot of diet and lifestyle changes at once, and if they’re healthy changes, they may bring about some healthy effects.