about the best diet for high blood pressure,

or heart disease, or diabetes.

Where do you go?

Do you go to a website sponsored by Big Pharma

that wants to sell you pills to fix your problem?

Or, do you want to treat the cause?

Welcome to the Nutrition Facts Podcast

with the latest peer- reviewed research

on the best ways to eat healthy and live longer.

Today we take a close look at a multi-faceted

and often misunderstood root vegetable.

And we start with a little trick about lowering their glycemic impact.

If you systematically pull together all the best studies

on potato consumption and chronic disease risk,

an association is found for the risk

of type 2 diabetes and hypertension.

Yeah, but that was for French fries.

Consumption of boiled, baked, or mashed potatoes was not

associated with the risk of high blood pressure,

but there was still a pesky link with diabetes.

Overall, potato consumption is not related to the risk

for many chronic diseases, but boiled potatoes

could potentially pose a small increase in risk for diabetes.

That's one of the reasons some question whether they should

be counted as vegetables when you're trying to reach

your recommended daily servings of fruits and vegetables.

If you look at other whole plant foods—nuts, vegetables,

fruits, and legumes (which are beans, split peas,

chickpeas, and lentils)— they're associated with

living a longer life.

Significantly less risk of dying from cancer,

dying from cardiovascular diseases like heart attacks,

and 25 percent less chance of dying prematurely

from all causes put together.

But no such protection is gained from potatoes

for cancer, heart disease, or overall mortality.

So, the fact that potatoes don't seem to affect mortality

can be seen as a downside.

Now, it's not like meat, which may actually

actively shorten your life, but there may be

an opportunity cost to eating white potatoes,

since every bite of a potato is a lost opportunity

to put something even healthier in your mouth—

something that may actively make you live longer.

So, potatoes are kind of a double-edge sword.

The reason that potato consumption may just have

a neutral impact on mortality risk is that

all the fiber, vitamin C, and potassium in white potatoes

might be counterbalanced by the detrimental effects

of their high glycemic index.

Not only are high glycemic impact diets robustly

associated with developing type 2 diabetes,

but current evidence suggests that

this relationship is cause-and-effect.

A front group for the potato industry called

the Alliance for Potato Research and Education

funded a study that found that intake of non-fried potato

does not affect blood sugar markers,

but that's compared with the likes of Wonder Bread;

so, that isn't really saying very much.

Foods with a glycemic index (GI) above 70

are classified as high-GI foods, high glycemic index foods,

and those lower than 55 are low-GI foods.

Pure sugar water, for example, is often standardized at 100.

White bread and white potatoes are way up there

as high glycemic index foods.

When you compare them to an intact grain, like barley groats

(also known as pot barley), a super-low GI food,

you can see how refined grains and potatoes are simply no match.

Is there any way we can have our potatoes and eat them too,

by somehow lowering their glycemic index?

Well, if you boil potatoes and then put them

in the fridge to cool, some of the starch crystallizes

into a form that can no longer be broken down

by the starch-munching enzymes in your gut.

However, the amounts of this so-called resistant starch

that are formed are relatively small, making it difficult

to recommend cold potatoes as the solution.

But when put to the test, you actually see a dramatic drop

in glycemic index in cold versus hot potatoes.

So, by consuming potatoes as potato salad, for instance,

you can get nearly a 40 percent lower glycemic impact.

The chilling effect might, therefore, also slow the rate

at which the starch is broken down and absorbed.

So, individuals wishing to minimize dietary glycemic index

may be advised to precook potatoes

and consume them cold or reheated.

The downside of eating potatoes cold is that they might not

be as satiating as eating hot potatoes.

But you may get the best of both worlds by cooling them

then reheating them, which is exactly what was done

in that famous study I profiled in my book How Not to Diet.

The single most satiating food out of the dozens tested

was boiled then cooled then reheated potatoes.

There's actually an appetite- suppressing protein in potatoes

called potato protease inhibitor II,

but the way you prepare your potatoes makes a difference.

Both boiled and mashed potatoes are significantly

more satiating than French fries.

That was for fried French fries, though.

What about baked French fries?

Folks had a big drop in appetite after eating

boiled mashed potatoes, compared to white rice or white pasta,

which is right where fried French fries were stuck,

as well as baked French fries.

So, though they may be your BFF, they're not very satiating.

In our next story, broccoli, vinegar, and lemon juice

are put to the test to blunt the glycemic index of white potatoes.

White potatoes have a high glycemic index, and consumption

of high glycemic impact foods may increase the risk of diabetes.

Normally after a meal, we'd like our blood sugars

to just gently, naturally rise and fall.

But with high glycemic foods like potatoes, you get an

exaggerated blood sugar spike which leads your body

to over-compensate with insulin forcing your blood sugars

lower than when you started, which results in negative metabolic

consequences such as a rise in triglyceride fats in the blood.

However, potatoes are a good source of potassium, vitamin C,

and polyphenols, which may counterbalance the glycemic impact.

This may explain why potatoes appear to have a neutral effect

when it comes to lifespan, unlike other whole plant foods,

that have been associated with actively living longer.

In my last video, I detailed my nip-and-nuke method,

where the act of chilling potatoes can dramatically lower their

glycemic index, even if you then reheat them in a microwave.

How else might we reduce the glycemic impact of white potatoes?

The answer is the same way you make anything better

in your nutritional life—add broccoli.

The co-consumption of two servings of cooked broccoli

with your mashed potatoes would certainly do it,

immediately cutting the insulin demand by nearly 40 percent.

In contrast, adding chicken breast makes things worse

and adding tuna fish makes things even worse still,

nearly doubling the amount of insulin your body has to pump out.

Why does plant protein make things better,

but animal protein make things worse?

Because decreased consumption of branched-chain amino acids

improves metabolic health. I cover this in my book

How Not to Diet as well as my video on the topic.

Speaking of How Not to Diet, remember the section on vinegar?

Here are the blood sugar and insulin spikes someone with

prediabetes can get from eating a bagel.

Eat that same bagel with a tablespoon or so

of apple cider vinegar diluted in about a quarter cup of water,

though, the impact is significantly less.

Does it work for potatoes too?

Simply chilling potatoes may cut down on the blood sugar

and insulin spikes, but to get significant drops in both,

you just have to add about a tablespoon of vinegar

to drop levels by 30 to 40 percent.

And that was just plain white distilled vinegar.

Is it the vinegar itself, or would any acidy condiment do?

In a test tube, lemon juice appeared to have a remarkable

starch-blocking effect, but you can't know if it works

in people, until you... put it to the test.

And indeed, lemon juice reduces the glycemic responses to bread.

And not just by a little, but by like 30 percent.

Now, the subjects were drinking a half cup of lemon juice,

but that makes it even more remarkable that it helped because

that added an extra half teaspoon of sugar,

and yet they still had a better blood sugar response.

Vinegar is more potent, though.

Just one to two tablespoons a day of vinegar diluted in water

can significantly improve both short- and long-term

blood sugar control in diabetics, which is why clinicians

may want to incorporate vinegar consumption as part

of their dietary advice for patients with diabetes.

Finally today, are yellow- fleshed potatoes

healthier than white? Let's find out.

The high glycemic impact of potatoes may increase the risk

of type 2 diabetes, perhaps by chronically overstimulating

the insulin-producing cells in the pancreas.