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
nonvegetarian 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 appeared 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 foods.
So how about a scoring system that just adds up how many cups of fruit,
vegetables, whole grains, and beans, split peas, chickpeas and lentils,
and how many ounces of nuts and seeds per thousand 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 doughnuts into your face.
So, you could 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, dairy, or eggs —
or added sugars and fats.
My favorite proportional intake measure is McCarty's Phytochemical Index.
I love it because its 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, 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 and BMI compared with non-vegetarians.
And even more studies show that high intakes of 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 their 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 decrease body fat.
So it's not all or nothing.
Any steps we can make to increase our whole plant food intake
may be beneficial.
A 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 such 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 in plants that alleviate inflammation
and quench free radicals.
And indeed, things seemed to improve as people ate more and more plants.
No wonder researchers found 91% lower odds of prediabetes
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 3-year period among those eating more plants.
Even mental health was impacted. About 80% less depression,
2/3 less anxiety, 70% less psychological distress.
What about the Dietary Phytochemical Index and benign breast diseases,
such as fibrocystic diseases, ductal ectasia, 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 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 Sixpack doing?
Here is the latest data on the standard American diet:
3% of calories come from beans and nuts;
3% from fruit; 5% is vegetables;
23% from grain; 17% is added sugars,
like candy and soda and other junk;
23% comes from added fats— butter, margarine, 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 with a score of 74.
Neither lard nor candy are phytonutrient-rich either,
so taking away the added fats and oils, we’re down to 34.
But the grain category is a combination
of both whole grains— rich in phytonutrients—
and refined grains, which had 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 cornstarch.
Yikes, down to 15! But it gets worse.
2/3 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 excluded refined grains,
potato products, hard liquors, and added sugars and oils could have a
[perfect dietary index rating] of 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.
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images, or studies mentioned here,
please go to the Nutrition Facts Podcast landing page.
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detailed information you need –
plus, links to all of the sources we cite to each of these topics.
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with more than 100 recipes for
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