Thursday, December 16, 2010

Interview with Chris Voigt of 20 Potatoes a Day


Chris Voigt is the executive director of the Washington State Potato Commission, which supports and promotes the Washington state potato industry (1). On October 1st, Mr. Voigt began a two month, potato-only diet to raise awareness about the health properties of potatoes. It was partially in response to the recent decision by the federal WIC (Women, Infants and Children) low-income assistance program to remove potatoes from the list of vegetables it will pay for. Mr. Voigt's potato diet has been a media sensation, leading to widespread coverage in several countries. He maintains a website and blog called 20 Potatoes a Day.

Diet Facts

For 60 days, Mr Voigt's diet consisted of nothing but potatoes and a small amount of cooking oil (canola and olive), with no added nutritional supplements. Based on what he has told me, I estimate that 10-15% of his calories came from fat, 10% from protein and 75-80% from high-glycemic carbohydrate. His calorie intake ranged from 1,600 kcal (first 3 weeks) to 2,200 kcal (remaining 5.5 weeks) per day. Prior to the diet, he estimated that his calorie requirement was 2,200 kcal, so he attempted to stay as close to that as possible.

Health Markers

Mr. Voigt has posted the results of physical examinations, including bloodwork, from the beginning, middle and end of the diet. The change he experienced during that time is nothing short of remarkable. He shed 21 pounds, his fasting glucose decreased by 10 mg/dL (104 to 94 mg/dL), his serum triglycerides dropped by nearly 50%, his HDL cholesterol increased slightly, and his calculated LDL cholesterol dropped by a stunning 41% (142 to 84 mg/dL). The changes in his HDL, triglycerides and fasting glucose are consistent with improved insulin sensitivity (2, 3), and are not consistent with a shift of LDL particle size to the dangerous "small, dense" variety (4).

What was your diet like prior to the potato diet?
My best estimate is that it was probably a little better than the average US citizen only because of a high rate of produce consumption. I generally would eat about 10 servings of fruits and vegetables a day. But I ate everything else too. I would eat a wide range of food, a little bit of everything, including foods that aren’t considered “healthy”.
You essentially ate nothing but potatoes, fat and flavorings for two months. Can you give us an idea of how much fat you were eating? What kind of fat was it?
I averaged about 2 tablespoons of cooking oil a day over the span of the 60 days. Canola oil was used for frying and olive oil was used for roasting.

How was your digestion?
Potatoes are pretty easy on the digestive system. I actually got a lot of emails from people who suffer from severe digestive disorders and literally, potatoes are the only thing they can eat. My 60 days of potatoes was nothing compared to some folks with these digestive disorders. I was getting a lot of fiber so things were pretty regular, but not too regular :)

You lost 21 pounds during your two months of eating only potatoes. Do you have a sense of whether it came out of fat, muscle or both? For example, did your pants become looser?
Pants definitely became looser. I also noticed it in my neck size for shirts. I’m assuming most all of it was due to fat loss.

Do you think you were able to meet your calorie goal of 2,200 calories per day? Were you hungry during the diet?
I was not meeting the goal of 2,200 calories a day during the first 3 weeks of the diet. During the first three weeks of the diet I only ate until I was full. I didn’t realize that potatoes would give me such a high sense of fullness after each meal. So for those first 3 weeks, I was only consuming about 1,600 calories a day. After the third week I had lost 12 pounds and realized that I needed to change strategy. I then began to eat more potatoes despite the sense of fullness I was experiencing. So for the remaining 5 ½ weeks I was very diligent about eating the 2,200 calories. I continued to lose weight but at a slower place. I lost an additional 9 pounds over the course of those remaining 5 1/2 weeks. At the start of my diet I estimated, via a couple different on line calorie calculators, that I burn about 2,200 calories a day. Since I continued to lose weight, I’m assuming I actually burn closer to 2,800 calories a day. Something that may have also played a role in continued weight loss was the amount of resistant starch I was getting from potatoes. I ate a lot of cooked potatoes that had been refrigerated. These are generally higher in resistant starch. If I were to do the diet again, I would like to set up an experiment to gauge the effect of resistant starch.
What foods did you crave the most?
I craved mostly foods that had a “juicy crunch”, like an apple, or cucumbers, or carrots, or celery. I never acquired a taste for raw potatoes so virtually all the potatoes I consumed were cooked. No matter how you cook your potatoes, you always get that same soft cooked texture. I craved foods with a crisper texture.
How was your energy level?
My energy level was very good the entire time of the diet. I really didn’t notice a change in energy at the start of the diet so I assumed that the potato diet didn’t have a positive or negative effect on my energy level. It wasn’t until I finished the diet and started to consume other foods that I noticed my energy level has seemed to drop a bit.

How did you feel overall? Were there any unexpected effects of the diet?
I felt really good on the diet. I had lots of energy, slept good at night, and seemed to avoid the cold viruses that circulated at home and work.

The only unusual thing that occurred is what my wife told me. I’m a habitual snorer. The day I started eating only potatoes, my snoring stopped. It restarted the day I started to include other foods in my diet. I’m assuming it was just some weird coincidence but that’s what she tells me.

My doctor and I expected my cholesterol to drop but not at the level we saw. I’ve had borderline high cholesterol for the past decade. I started the diet at 214 and saw it drop to 147 at the end of 60 days. We anticipated a drop of maybe 10-25 points. It was a huge surprise to see a 67 point drop.
Your fasting glucose went from 104 mg/dL, which I consider high, to 94 mg/dL, which is on the high side for someone eating a high-carbohydrate diet, but within the clinically normal range. Do you have a family history of diabetes?
No history of diabetes. My parents are in their early eighties and their parents lived to their 70’s and 80’s with no history of type one or two diabetes.

Reading your blog posts, it seemed like you were having a hard time with the diet at first, but after a while you complained less and even seemed to enjoy it at times. Did you get used to it?
I would say that week 2 and 3 were probably the hardest. The first week was easy probably because of the novelty of the diet. Then reality set in for week 2 and 3. After that, I found my groove and it got easier. During the work week was easy but weekends, particularly Sunday’s, were the hardest. During the work week I did most of my eating at my desk so I wasn’t around a lot of other people eating or surrounded by other foods. Weekends were more difficult because I was around other people every meal and always had other foods in front of me at home.
What kinds of potatoes did you eat?
I literally ate every kind of potato I could get my hands on. I ate yellow skin/yellow flesh potatoes, red skin/white flesh, red skin/red flesh, purple skin/white flesh, purple skin/purple flesh, russet potatoes with white flesh, russet potatoes with yellow flesh, white potatoes, yellow potatoes with white flesh, purple fingerlings, yellow fingerlings, red fingerlings and numerous experimental varieties.
Did you peel them or eat the skin?
I ate the skin at least 90% of the time if not more. There is a myth that all the nutrition in a potato is in the skin or right under the skin. That’s not true, there are nutrients spread throughout the potato but most of the fiber is located in the skin.
What variety of potato is your favorite?
It really depended on the cooking method. For frying, I preferred russet potatoes. For baking, I preferred red potatoes. For mashed, I preferred yellow potatoes. For roasting, a toss-up between russets and reds.
How long did it take you after the diet ended to eat another potato?
As strange as it sounds, potatoes were my first two meals after my diet ended. I was saving my first non-potato meal for a special event that was planned at the local Head Start facility. The beef, dairy, apple, and potato producers put together a nice dinner event and nutrition workshop for all the kids and their parents at the Head Start center in Moses Lake. I still eat potatoes pretty regularly, but most of the time now I’m eating them with more than just seasonings.
Are there any other facts about potatoes you think Whole Health Source readers might find interesting?
Just a reminder that I’m not encouraging anyone to follow in my footsteps and eat just potatoes. This diet is not intended to be the next “fad” diet but was simply a bold statement to remind people that there is a tremendous amount of nutrition in a potato. There is no one food product that can meet all of your nutritional needs. I fully support a well balanced healthy diet, which potatoes can be a part of.

In 2008, the United Nations declared it to be the “Year of the Potato”. This was done to bring attention to the fact that the potato is one of the most efficient crops for developing nations to grow, as a way of delivery a high level of nutrition to growing populations, with fewer needed resources than other traditional crops. In the summer of 2010, China approved new government policies that positioned the potato as the key crop to feed its growing population. The Chinese government formed a partnership with the International Potato Center in Peru to help them facilitate this new emphasis on the potato.
Thanks Chris, for doing your experiment and taking the time to share these details with us!

In the next post, I'll give my interpretation of all this.


David said...

how did he get all the essential amino acids?

Nathaniel said...

It is my understanding that the small amount of protein in potatoes contains all essential amino acids.

In theory, you could eat such a diet and not experience any protein deficiencies, if my information is correct.

Fascinating stuff Stephan... I welcome it with enthusiasm because I love potatoes!

I can't wait to hear your analysis.

Dream World said...

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Aaron Curl said...

Interesting! I love potatoes! I have heard though that eating them raw is bad. I'm still on the fence about this. I have eaten maybe 3-4 in the last year since going "paleo".

Derek H said...

I'm guessing the improvement in his lipids and blood glucose was due mainly to the weight loss, similar to the Twinkie Professor.

I can imagine the satiating qualities of that amount of potatoes was hard to stomach on most days.

But I believe there is enough information to alleviate the potato fear - and it's a good side kick to grass fed roasts. Provides a great vehicle for butter!

Peter said...

I bet you can lose weight on any boring diet as your urge to stuff yourself goes away. I ate breadfruit in coconut sauce practically every meal for two years in the Peace Corps in Micronesia and got very skinny.

Roberto said...


"I bet you can lose weight on any boring diet as your urge to stuff yourself goes away."

Keep in mind, that's how every healthy pre-industrial culture ate, to a certain extent. Of course, they would have had more variety than this experiment.

Sounds the like the perfect relationship with food to me. An interest in it when you're hungry, and an abrupt disinterest in it when you're not. Food is not meant to be addictive.

No stuffing yourself full of fudge and brownies after Christmas dinner muttering "I'm so stuffed, why am I still eating?"

Helen said...


R. K. said...

I suspect resistant starch from cold potatoes as one major contributor to his weight loss. Another possibility: a bland diet, per Seth Roberts Shangri-La Diet hypotheses. What I am most curious about is your opinion on whether this experiment, as well as the Kitava diet, contradict the arguments of the low-carb enthusiasts, who consider white potatoes to be not much different than white sugar.

LeenaS said...

Sounds reasonable. Daily portion of 30 grams in almost decent vegetable oil (canola) + much, much more in mainly saturated body fat might make a decent fat profile - especially in absence of fructose, grains, excessive omega 6's and many other toxins.

Thanks for the interview, Stpehan!

With regards,

Might-o'chondri-AL said...
This comment has been removed by the author.
JBG said...

Might-o'chondri-AL, no offense, but I find your posts lengthy and impenetrable.

Here is one thought that might help: Compose in a Word doc, thinking very carefully about what your point is, and trying to express it in a few words in ordinary English. Only when you think you've got it down (maybe run it by a friend), put it here.

I don't have a way to send to you privately. Please be assured that this note is intended to be friendly and constructive.


John said...

This post does not show up on my blog updates: has anyone else noticed this?

JBG, you don't have to read his [Mighto's] comments. It is on topic and informative.

Might-o'chondri-AL said...
This comment has been removed by the author.
Stephan Guyenet said...

Hi David,

As Nathaniel said, potatoes contain all the essential amino acids.

Hi Derek,

I think the improvements in his lipids were partially due to fat loss, and partially due to a calorie intake somewhat below his previous level per se.

Hi Peter,

Diet palatability may influence body fat regulation, that's something I'm still learning about.

Hi R.K.,

Although it's only one person, I do think this is inconsistent with the hypothesis that carbs cause fat gain and ill health. Potatoes are definitely not the same as white sugar.

I've been reading Seth Roberts' writing some because I've been interested in diet palatability and body fat lately.

Stephan Guyenet said...

Hi John,


Has anyone else here had the same problem (posts not showing up in their RSS reader)?

Stephan Guyenet said...

Hi Might-o'chondri-AL,

Comment away. By the way, your last two comments got stuck in my spam filter and I had to publish them manually. Not sure why. I only published one because they seemed redundant, but I'll publish the other one as well if you request it.

I have to disagree with your assertion that a compound in cooked potatoes inhibits alpha-glucosidase, leading to slower starch digestion and less post-meal glycemia. Potatoes have one of the highest glycemic index of any food, indicating a fast rate of starch digestion. Many plant foods contain digestive enzyme inhibitors but they're mostly denatured by heat.

MsCFaith said...

I admire Mr Voigt 'cause not everybody has the patience and perseverance to go on a strict diet. I know I won't last eating potatoes the whole day.

Health Blog

thaneverbefore said...

hey stephan,

since you asked, this post didn't show up on my google reader. just noticed it because i subscribe to comments as well.

Might-o'chondri-AL said...
This comment has been removed by the author.
Lisa said...

My latest RSS entry of this blog is 'Potatoes and Human Health, Part II' from 2 months ago.

David Pier said...

I think one relevant thing that didn't get mentioned in the post is the reasoning behind WIC dropping potatoes. I think the problem is rigid and inappropriate categories. Potatoes are classified as vegetables, and Russets do a relatively poor job of supplying what people expect from vegetables. I'm sure WIC still pays for bread, which potatoes are superior to. If they could get away from their "food group" mentality, they might be able to make reasonable decisions.

Unknown said...

Steve love this site!
Can anyone help me understand if sweet potatoes belong on a low carb diet? I can do without white potatoes but love sweet potatoes but don't want to derail what I'm doing. I'm thinking 1 every couple of days.

Might-o'chondri-AL said...
This comment has been removed by the author.
Gabriella Kadar said...

Mr. Voigt stopped snoring as soon as he started the potato diet because it provides a great deal of potassium.

The average north american diet is unbalanced in regards to sodium/potassium. This is also why as soon as he stopped the potato diet and despite the fact that he had lost weight, he began to snore again.

Excess sodium, in regards to potassium results in tissue edema. Fluids redistribute in the body due to the supine sleeping position resulting in swelling of tissues in the throat and nasal passages. This increases airway resistance and can result in snoring even in people who are not overweight.



Unknown said...

You might have a food intolerance if you stopped snoring when you eliminated all non potato food and it returned upon resuming a regular diet. When I eat dairy I snore. Dairy is very mucus producing. If your curious you could eliminate dairy for a few weeks to see if the snoring goes away.

Jenny said...

Re potatoes and blood sugar. ANY carbohydrate can be eaten safely by a person with completely functioning glucose metabolism, as is the case with the man doing this experiment.

But if a person is hyperinsulinemic or insulin deficient, the outcome of eating all that pototo starch would be very different. So this experiment only confirms that if one doesn't have genes that predispose to diabetes or hyperinsulinism, potatoes are a good choice of carbohydrate.

But to conclude from this that it means that potatoes are a "safe" carb is like concluding that diesel is a safe fuel for your Ford because it works well in a Mack truck.

Anyone with diabetes and a blood sugar meter can see the impact of potato carbs on their blood stream, and it can be intense.

The low carb diet doesn't promote health for everyone, just for people with genetic profiles (or damage) that make it tough for them to metabolize sugars and starches.

Might-o'chondri-AL said...
This comment has been removed by the author.
Anonymous said...


"So this experiment only confirms that if one doesn't have genes that predispose to diabetes or hyperinsulinism, potatoes are a good choice of carbohydrate."

That's quite a leap of faith. We don't know what his fasting insulin was. We don't know what his genes are. Given that he had high cholesterol, high glucose, high tris, then I would assume he already had the metabolic syndrome to some degree and may have been insulin resistant.

If anything, I conclude the opposite: that certain types of high-carb diets can heal a person with a damaged metabolism.

Unknown said...

his cholesterol went down to 147 - yikes! is he praising that number? theres another example of misinformation and repeating something over and over again. his body was telling him to eat butter, egg yolks and liver.

Allan Folz said...

Hmm, high-carb, franken oils, and omega-6. Yet, there _is_ one conspicuous absence, and no one has mentioned it... wheat

I'll admit this has me a little bummed. I'm always trying to justify a limited amount of homemade bread and baked goods are OK. The more I learn the more it seems probably not.

It would be nice if someone at the Washington State Wheat Commission could respond with a similar self-experiment. I would be very interested in the results.

Stephen, I'm guessing this occurred to you as well? I hope it will be part of your upcoming interpretation.

Anonymous said...

Song about eating nothing but potatoes:

majkinetor said...

So, nobody noticed conflict of interest here ?

Miguel said...

Mr. Voigt did an experiment with something that many people in Puerto Rico are doing for many years, eating potatoes, carrots and beets only, and all of them are experiencing a good health. Any can come with any scientific explanation but the reality is that many people are living only with these vegetables including my self that started the diet 8 month ago. You can get more information by visiting .

JBG said...

Miguel's link looks very interesting. Does anyone know of an internet tool for translating Spanish to English in large scale amounts?

Atlanta Plastic Surgeons said...

never thought that potatoes could e a cure to a diet plan.Hope it works for I love potato however it is served to me.I always avoided it thinking it would add to my weight.
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Miguel said...

JBG: I think Google has a translator but not sure. I asked Dr. Norman about this, he told me they are working on translating the site.

Miguel said...


You have to understand the sugar problem in individuals are created by their wrong food and I'm talking about grains milk and other related to grains. There are many but many people in Puerto Rico that they change their diet to potatoes, carrots beets, liquid yeast, and only these fruits: apples, pineapples (if you tolerated them) and papayas. And if you want the best omegas and vitamin E get these from first cold press olive oil.

Anonymous said...

Google Chrome has a builtin translation ability:

Unknown said...

Miguel, your statement that sugar problems in people are caused by the wrong foods isn't correct for everyone. I produce no insulin, and my type 1 diabetes emerged after a virus (which is common). Food did not "cause" these problems, and any carbohydrate I eat will spike my glucose levels without me taking insulin.

Progressively Defensive said...

That's 50-60g of protein a day. I guess it will do adequately, but for a 174 lbs. man (at the end) that is not a lot. I think he lost a lot of muscle in those 21 lbs.

Still it's a good part of a diet, eh.

Miguel said...

Hi Candice

You are correct, Type 1 is different, but you can try the potato and carrots diet for 2 weeks to see how your sugar behaves, but this is under your own risk, I'm not responsible to any problem happens to you. I have hear of many people in Puerto Rico that are saying tha they have dropped their insulin shots. I you decide to try use Yukon potatoes.

Fred Hahn said...

Does this guy have any documented proof that he ate only potatoes for 60 days? Did anyone ask him?

Anonymous said...

I love this blog! Anything I need to know about improving my diet is right here! PLUS... I don't have to eliminate a food group to stay healthy!! Thank you Stephan

spfldo said...

The scariest thing about the diet is all the fat was grain oil. Very inflammatory in the long run. He ought to try using ghee or lard to fry his taters.

For├ža SDV said...

Incredible! What Loren Cordain would say about this?

The scariest thing about the diet him is all the fat was grain oil.

No words...

Unknown said...

Check this out for amino acid concerns.....

Unknown said...
You should read Dr. McDougall's columns and his book "The Starch Solution" or Dr. Neal Barnard's discussion of vegan diet reversing diabetes.