 What if just one lifestyle change could help you avoid getting cancer? Or diabetes? Or heart disease? Or high blood pressure? This one change could cut your risk of chronic disease and add years to your life. Well, the simple solution to so many of these problems is to eat a healthy diet. In other words, one centered around whole plant foods. Welcome to the Nutrition Facts Podcast. I'm your host, Dr. Michael Greger. As you know, I like to put things to the test, and today we're going to ask you to do that with your diet using the Phytochemical Index. Anything with the word chemical in it may sound a little fishy, but phytochemicals can be good for you. Here's the first story. How do you rate the quality of people's diets? Well, what could be more nutrient-dense than a vegetarian diet? Indeed, if you compare the quality of vegetarian diets compared to non-vegetarian diets, the more plant-based diets do tend to win out, and the higher diet quality in vegetarian diets may in fact help explain better improvements in health outcomes. However, vegetarians appear to have higher refined grain intake, eating more foods like white rice and white bread that have been stripped of much of their nutrition. So just because you're eating a vegetarian diet doesn't mean you're necessarily eating optimally healthy. Those familiar with the science know the primary health importance of eating whole-plant food. So how about a scoring system that just adds up how many cups of fruit, vegetables, whole grains, and beans, split peas, chickpeas, lentils, and how many ounces of nuts and seeds per 1,000 calories, with or without counting white potatoes? Well, just looking at the total intake of whole-plant foods doesn't mean you're not also stuffing donuts into your face, so you can imagine proportional intake measures based on calories or weight to determine the proportion of your diet that's whole-plant foods. In that case, you'd get docked points if you eat things like animal-derived foods, meat-dearried eggs, or added sugars and fats. My favorite proportional intake measure is McCarty's Phytochemical Index. I love it because it's sheer simplicity defined as the percent of dietary calories derived from foods rich in phytochemicals. So it's a score from 0 to 100, the percentage of your calories that are derived from foods rich in phytochemicals, which are biologically active substances naturally found in plants that may be contributing to many of the health benefits obtained from eating whole-plant foods. I mean, you know, monitoring phytochemical intake in the clinical setting could have great utility in assisting people with optimizing their dietary intake for optimal health and disease prevention. However, the quantification of phytochemicals in foods or tissue samples is impractical, expensive, laborious, but hey, this concept of a phytochemical index score could be an alternative, simple method of monitoring phytochemical intake. Theoretically, a whole-food plant-based or vegan diet that excluded refined grains, white potatoes, hard liquors, and added sugars and oils could achieve a perfect score of 100, whereas sadly, the most current American diets might be lucky to hit 20. Let's see what's going on. In 1998, our shopping baskets were filled with about 20% whole-plant foods, and more recently that has actually shrunk. Wouldn't it be interesting if researchers used this index to try to correlate it with health outcomes? That's exactly what they did. Look, we know that studies have demonstrated vegetarian diets have a protective association with weight and body mass index. Five dozen studies have shown that vegetarians had significantly lower weight in BMI compared with non-vegetarians. And even more studies show that high-intensive fruits, vegetables, whole grains, and beans may be protective regardless of meat consumption. So researchers wanted to use an index that gave points for whole-plant foods. They used a phytochemical index and tracked people's weight over the next few years, which again I profiled in my video, Calculate Your Healthy Eating Score on a Scale of 0 to 100, simply reflecting what percentage of your diet is whole-plant foods. And even though the healthiest eating tier only averaged a score of about 40, which meant the bulk of the diet was still made up of processed foods and animal products, just making whole-plant foods a substantial portion of the diet may prevent weight gain and decreased body fat. So it's not all or nothing, any steps we can make to increase our whole-plant food intake may be beneficial. Couple more studies have been performed since, and they all point in the same direction, about a third of the odds of abdominal obesity at higher healthy plant intake, and significantly lower odds of high triglycerides. So the index may be a useful dietary target for weight loss, where there's less focus on calorie intake and more on increasing intake of these high-nutrient lower calorie foods over time. The latest study published 2020 suggests the same is true for childhood obesity. Even at the same weight, the same amount of belly fat, those eating plant-based have higher insulin sensitivity, meaning the insulin they make works better in their body, perhaps thanks to the compounds and plants that alleviate inflammation and quench free radicals. And indeed, things seem to improve as people eat more and more plants. No wonder, researchers found 91% lower odds of pre-diabetes for people getting more than half their calories from healthy plant foods. Significantly lower odds of metabolic syndrome and high blood pressure, only about half the odds of being diagnosed with hypertension over a three-year period, among those eating more plants. Even mental health was impacted. About 80% less depression, two-thirds less anxiety, 70% less psychological distress. What about the dietary phytochemical index and benign breast diseases, such as fibrocystic diseases, ductalactasia, fatty necrosis, and all sorts of benign tumors? The same thing was found. 70% lower odds of those diseases. OK, but what about breast cancer? A higher intake of healthy plant foods was indeed associated with a lower risk of breast cancer, even after controlling for a long list of other factors, and not just by a little bit, eating twice the proportion of plants compared to the standard American diet was linked to more than 90% lower odds of breast cancer. What evidence do we have that's scoring higher is actually better? Let's find out. A few years ago, a proposal was published for a healthy eating index, and I thought it might be interesting to look at the latest USDA dietary survey to see how the standard American diet is doing. The index is simple. It's a score of 0 to 100, which simply represents the percent of dietary calories derived from foods rich in phytochemicals. Phytochemical is just a more technical term for phytonutrient, since nutrient implies essential for life, whereas phytochemicals are merely essential for a long, healthy life. So if 1% of our diet is composed of phytonutrient-rich food, our diet gets a score of 1. If that's where half of our calories come from, then we score 50. And if that's all we eat, we can max out at 100, 100%. How are Jane and Joe six-packed doing? Here's the latest data on the standard American diet. 3% of calories come from beans and nuts, 3% from fruit, 5% is vegetables, 23% from grains, 17% is added sugars, like candy and soda and other junk, 23% comes from added fats, butter, margin, oil, shortening, and 26% of the American diet is meat, dairy, and eggs. For the healthy eating index, we only get to count phytonutrient-rich foods, since they're the ones most associated with chronic disease prevention, treatment, and cure. So first off, the reason they're called phytonutrients is that by definition they are found in plants, derived from the Greek word phyton for plant. So automatically we start out with a score of 74. Neither lard nor candy are phytonutrient-rich either, so taking away the added fats and oils, we are down to 34. But the grain category is a combination of both whole grains, rich in phytonutrients, and refined grains, which have the phytonutrients largely removed. Only 4% of the American diet is composed of whole grains, like oats, barley, whole wheat, brown rice, and the rest is highly processed, garbage like white flour and corn starch. Yikes, down to 15, but it gets worse. Two-thirds of our vegetables are white potatoes, half of which are potato chips. The average American eats 23 calories of potato chips every day, but none of the white potato products count since they contain relatively few phytonutrients. Similarly, a third of our fruit calories are low phytonutrient juices, and so the typical American diet rates 12 out of 100. So on a scale of like 1 to 10, we get about a 1. How do you score a perfect 10? Theoretically, a vegan diet that has excluded refined grains, potato products, hard liquors, and added sugars and oils could have a perfect dietary index rating of a 100. Sadly, the score of most current American diets would be unlikely to be as high as 20. Yeah, we wish it were 20. Which means that there is quite ample room for improvement. We would love it if you could share with us your stories about reinventing your health through evidence-based nutrition. Go to nutritionfacts.org slash testimonials. We may share it on our social media to help inspire others. To see any graphs, charts, graphics, images, or studies mentioned here, please go to the Nutrition Facts podcast landing page. There you'll find all the detailed information you need, plus links to all the sources we cite to each of these topics. My latest two books are How to Survive a Pandemic, available on e-book, audio book, or actual book, and the How Not to Diet Cookbook, with more than 100 recipes for delicious and nutritious meals. All proceeds I receive from the sales of my books go to charity. NutritionFacts.org is a non-profit science-based public service where you can sign up for free daily updates on the latest in nutrition research via bite-sized videos and articles. Everything on the website is free. There's no ads, no corporate sponsorship. It's strictly non-commercial, not selling anything. I just put it up as a public service as a labor of love as a tribute to my grandmother, whose own life was saved with evidence-based nutrition.