Wednesday, December 19, 2012

The Potato Diet

In 2010, I wrote a series of blog posts on the health properties of potatoes (1, 2, 3).  The evidence showed that potatoes are non-toxic, filling per calorie, remarkably nutritious, and can be eaten as almost the sole source of nutrition for extended periods of time (though I'm not recommending this).  Traditional South American cultures such as the Quechua and Aymara have eaten potatoes as the major source of calories for generations without any apparent ill effects (3).  This is particularly interesting since potatoes are one of the highest glycemic and most insulin-stimulating foods known.

Potatoes appear not to cause fat gain, and in fact frequently cause fat loss and improve metabolic health in people who are overweight.  The Washington Potato Commissioner Chris Voigt illustrated this in his two month potato-only diet, during which he lost 20 lbs and greatly improved his metabolic and cardiovascular biomarkers without feeling hungry.  I interviewed Mr. Voigt and gave my thoughts in a series of posts (4, 5).  Some people objected that Mr. Voigt may not have been impartial since he had an interest in making potatoes look good.  Although my gut feeling was always that he was being straightforward about his experience, it's nevertheless a reasonable concern.

This year, a fascinating thread appeared in the Mark's Daily Apple forum.  Apparently inspired by an exchange with Ray Cronise, someone decided to go on a potato diet and began losing weight rapidly (6).  The thread snowballed as other people joined in and found that they were also losing weight rapidly on the potato diet (potatoes, sometimes with a small amount of added fat).  It is worth noting that most of these people were coming from a primal-style low-carbohydrate diet*.  As of right now, the thread has 104 pages.

People have proposed explanations for this phenomenon, and some have been amusing, such as the attempt to explain the effect via the insulin-obesity hypothesis.

Those of you who followed my writing on food reward and "why we eat" will understand that fat loss is exactly what one would expect from a diet like this, and in fact the diet echoes the recommendations I published in 2011 for using food reward as a fat loss tool (7).  The potato diet works because:
  1. Potatoes have a low calorie density and a high satiety value per calorie.  
  2. Eating a diet that is composed almost exclusively of one food is low in reward, low-moderate palatability, low in variety, and has a high sensory-specific satiety.  Even if you dress up your potatoes as well as you can, you're still eating potatoes.  This tends to reduce calorie intake.
  3. Potatoes are nutritious enough (including complete protein) that they can be the sole source of calories for an extended period of time.  However, they are not a complete source of all micronutrients and deficiencies will eventually arise.
I don't recommend going on a potato-only diet.  However, it is a very interesting illustration of some key dietary principles.


* For the record, I'm not implying that the Primal Blueprint or other reduced-carbohydrate Paleo type approaches are fattening.  It is a fact that PB and similar approaches have helped many people lose fat and become healthier, and will continue to do so.

43 comments:

Luis said...

I followed a potato only diet for 30 days. I stopped the diet today and added some protein in the form of lean chicken breast and beef heart. The meal felt strange. My results after 30 days: 11 lbs of fat lost, 8 lbs. of LBM gained and a total BF reduction of 6%. I still maintained my normal gym routine and even added 2 days of bootcamp classes. Energy wasn't a problem in this diet. I was also using 10 grams BCAA everyday which could explain why I lost no muscle mass. I'm only going to take a week off and I'm quickly going to resume a potato only diet. Can't deny that I actually enjoyed it.

texasmax said...

So, without going back and actually reading the past write-ups, to paraphrase your 3 points, the Potato Diet works because potatoes 1) are filling, 2) don't taste that great (so you eat less), and 3) provide somewhat adequate nutrition? So the question is, are there other single foods, or small groups of foods, that might meet this criteria as well?

texasmax said...

Luis- do you know how your overall daily calorie intake during the potato period compared to the pre-period? And what was your rate of fat loss and LBM gain before the potato period?

Luis said...

Texasman- I was following a primal type diet with some leangain components. Although I remained low-carb the whole time. This proved to be a disaster. I did lose 60 lbs. over a period of almost 2 years (I consider this slow for the amount of effort that went into it) but I hit a plateau. For over 4 months, I couldn't shed the last 30 lbs. Out of desperation, I even tried a couple of months of phentermine and to my surprise, this didn't move any weight either. It wasn't until tried the starches that my weight started dropping. I was eating around 10 taters a day, roughly. During the pre-period, I always remained below my BMR+activity calorie target and worked out intensely. Back in 2006 I did a similar diet where I ate only fruits for 4 months. I never looked better in my entire life, so I knew this tater diet would work as well.

I also did blood work before I started the experiment and again today before I broke the diet. Last month, my results showed high cholesterol, triglycerides and iron levels. I'm curious to see how these changed after one month.

Peter said...

Excellent post, Stephan.

It's all about the math. 2 table spoons of oil gives you 250 calories. With 250 calories you can eat 1/3kg potatoes (0.66lbs). Which one, oil or potatoes are going to give you a better satiety?



Peter said...

* For the record, I'm not implying that the Primal Blueprint or other reduced-carbohydrate Paleo type approaches are fattening. It is a fact that PB and similar approaches have helped many people lose fat and become healthier, and will continue to do so.

Good point Stephan. Things are not black-and white. I've noticed 1 pack of cigerette's per day has a lot therapeutic effects just like the people affiliated with WAPF claim. 1 pack per day will induce lot of health benefits for many, especially for those who come from smoking 3 packs a day.

Ruth said...
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Steven Allan said...

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Peter said...

To prevent misunderstanding, the above tobacco example was pure trolling. The point was to highlight that besides lenght of adherance, base-line situation plays a huge role. Given a preponderance of evidence, there's no reason to believe that a paleo-diet lacking in carbohydrates and high in dietary cholesterol and SFA will induce beneficial long-term effects. A potato-rich diet seems like a much better idea.

What was interesting in Voigt's experiment was that his TC cholesterol came down about 60 points in two months despite maintaining steady 2200 calories per day. This is comparable to intensive, high-dose statin theraphy.

http://20potatoesaday.com/

Dave said...

Another nail in the coffin of the carbohydrate insulin hypothesis.

DH said...

Your just retarded now Stephan. Your posts of the past several months are garbage and you have no idea where you are heading now. Your food reward theory has gone belly up cuz its wrong and only has some effect when one is metabolically deranged/leptin resistant.

Chris Wilson said...

DH's comments notwithstanding, I think you are absolutely correct about this Stephan. I was also amused to read some of the dressed-up biochem explanations of Voight's success, when it seems that satiety, reward and energy-balance considerations are obviously more profound factors in the observed weight-loss. I agree that the experience of the Primal dieters is indicative of this.

BTW, I posted some questions to Dr. Johnson and yourself in the last post, which I'm still interested in if you have any thoughts. I'm reposting below:

“Stephan: However, this result does not imply that an excess of insulin action (determined both by insulin concentration and tissue sensitivity to insulin) is a causal factor in common obesity, or that hyperinsulinemia precedes insulin resistance in the etiology of common obesity.”
Johnson: Here is the remaining gap. Our results (in the controlled and artificial conditions it was conducted) do in fact show exactly that – that the excess of insulin IS required – because when we remove the excess insulin (and only the excess insulin) the obesity does not occur. Also, we clearly see hyperinsulinemia (seen within 1 week after HFD) precede both the obesity (~20 weeks after HFD) and IR (never) in our model.”

I think this is the crux of the issue here. Can we agree that a positive energy balance (i.e. “excess calories”) is a necessary condition for common obesity? If so, and both animal groups consumed sufficient calories to be fattening, the question is, where do those calories go? It’s obvious that insulin is a major hormone regulating the balance of energy between cells and blood.
Dr. Johson, are you saying that both mice maintained normoglycemia despite only the “hyperinsulinemic” mice gaining fat mass? If so, where the heck are the calories going? Muscular tissue? Increased maintenance respiration?
Although insulin plays a role in the CNS, it still seems to me that it operates mostly on short time-scales and is supposed to be responsive to blood glucose homeostasis. I guess the dispute is over what is “intact insulin signaling”? Do you think that variations in insulin signaling play a role in determining whether excess calories are disposed into fat tissue or by some other means (e.g. inhibiting lypolysis)?


donheff said...

Stephen. I enjoy your column as a rational counterpoint to zealots on the LCHF and Paleo approaches but I would like to hear your opinion on what people "should" do about weight and general health. Do you recommend that people simply experiment and do what works for them? Follow some specific structured approach?

I dropped from 192 to may 162 target/plateau on a relatively LCHF eating style that is satisfying and easy to stick with (one year in). I don't care why it worked but am interested in whether I should be experimenting with changes from a health/nutrition viewpoint. E.g., should I try increasing carbs like potatoes/rice on a self experimental basis?

Craig said...

"Another nail in the coffin of the carbohydrate insulin hypothesis."

No. They aren't mutually exclusive. Even if one hypothesis is proven, it wouldn't disprove the other.

M said...

Does the non-toxivity of potatoes also apply to people who suffer from autoimmune conditions? I've excluded all nightshades from my diet for this very reason.

Medjoub said...

Stephan, I'm interested in your take on the anecdotal reports suggesting that after long periods of time on bland diets, people will begin to gain weight excess weight again. My facts are probably light askew here, but I seem to recall that Lex Rooker had issues with spontaneously beginning to regain lost weight on a calorically-identical, all-meat diet. I've heard other (admittedly difficult to assess) similar stories. Is the same thing possible on a potato diet?

Sanjeev said...

Rooker doesn't eat ad lib.

one time that I remember he gained weight for an extended period of time. In response he consciously reduced the mass of meat he eats per day, irrespective of how full or sated or hungry he felt.

JJ said...

Chris W wrote "I think this is the crux of the issue here. Can we agree that a positive energy balance (i.e. “excess calories”) is a necessary condition for common obesity?"
***Yes. Makes sense to me as a general principle.

"If so, and both animal groups consumed sufficient calories to be fattening, the question is, where do those calories go? It’s obvious that insulin is a major hormone regulating the balance of energy between cells and blood."
***We showed that the calories were burned off by white adipose tissue that had been reprogrammed to expression uncoupling protein 1 (i.e. behaved a little like brown adipose tissue). This is an important part of the study that many people haven't picked up on.

“Dr. Johnson, are you saying that both mice maintained normoglycemia despite only the “hyperinsulinemic” mice gaining fat mass? If so, where the heck are the calories going? Muscular tissue? Increased maintenance respiration?”
***See above. And please note that the mice settled into normoglycemia. There was a period of glucose intolerance when they were young and growing. Thereafter, that had just enough insulin to keep them perfectly normoglycemic. This is a very key aspect of the study and separates it from a lot of other studies.

“Although insulin plays a role in the CNS, it still seems to me that it operates mostly on short time-scales and is supposed to be responsive to blood glucose homeostasis. I guess the dispute is over what is “intact insulin signaling”? Do you think that variations in insulin signaling play a role in determining whether excess calories are disposed into fat tissue or by some other means (e.g. inhibiting lypolysis)?”
***This field is still young. To date, most people have only looked at the effects of insulin in short time scales and therefore that is all they have found. The long-term studies involve deletion of insulin receptors. IR deletion in whole brain increases food intake, although now Jens Bruning has shown that insulin receptors in different regions of the brain have different roles and are apparently differentially susceptible to insulin resistance. The role of the insulin made locally in the brain is not yet clear. We are working on this.

Craig - "Another nail in the coffin of the carbohydrate insulin hypothesis." No. They aren't mutually exclusive. Even if one hypothesis is proven, it wouldn't disprove the other.
***Craig, you are a smart man! You can 'nail' other people's hypothesis with studies that are unrelated. We only said that preventing insulin hypersecretion prevents obesity under the conditions we studied, which by the way, includes the removal of brain insulin. I think one of the issues that the lay public has is trying to tie everything into ONE signal model.

Blue Quill Books said...
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TedHutchinson said...

I wonder if some of the impact of dietary change comes from changes in levels of chronic inflammation and makeup of our gut bacteria?

Here is a recent example.
An opportunistic pathogen isolated from the gut of an obese human causes obesity in germfree mice
Looking at the Pdf of the actual diet used by the human example. Is the BLAND nature of the cruel used responsible or is it the change in gut flora brought about by increased resistant starch improving numbers of commensal bacteria while use of Bitter melon reduces pathogenic forms?
Or perhaps the combination of both?

Could the types of food we consume alter the ratio of good/bad gut microbiota?
The intestinal microbiota in aged mice is modulated by dietary resistant starch and correlated with improvements in host responses.

Maybe Bacteria control host appetites? as well as fat storage?

I wonder how many Metabolic ward studies allow sufficient time for changes in appropriate intestinal microbiota to become established?

TedHutchinson said...

That should have read GRUEL not cruel.
Though on reflection, tinned porridge 4 times daily for 6 months sounds a bit cruel to me.

Jane said...

It certainly is very interesting that with low insulin, white adipose tissue gets reprogrammed to be more like brown. It seems UCP1 expression is dependent on the beta-3 adrenergic receptor
http://www.ncbi.nlm.nih.gov/pubmed/8675704

..which is downregulated by insulin
http://www.ncbi.nlm.nih.gov/pubmed/8202547

So now we need to know whether constant low insulin is the way to get this re-programming, or whether periodic low insulin will do. Jim Johnson tells us that feeding the animals in a small time window prevents the obesity. So this is how intermittent fasting works! I thought it was just by inducing autophagy.

I think Jim is right, people are neglecting this aspect of his work. I was too. This is starting to sound to me like the holy grail of obesity research. Calories don't matter if you can burn them off! And keep warm too, OMG.


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JJ said...

Jane -

Insulin signalling regulates autophagy... these things are all involved - in series.

There is no holy grail, just complicated biology! But I appreciate the enthusiasm.

Oh, yes, and sorry for putting my reply on the potato section... I'm not very good at this... maybe someone can paste it on the other place...

Chris Wilson said...

Dr. Johnson
Thanks for your reply!
Brief follow-up:
"We showed that the calories were burned off by white adipose tissue that had been reprogrammed to expression uncoupling protein 1 (i.e. behaved a little like brown adipose tissue). This is an important part of the study that many people haven't picked up on"

This is fascinating. So you're saying that excess insulin may inhibit brown adipose like behavior of white adipose tissue. I guess this makes sense that if insulin levels are elevated it would be signaling the body to store rather than burn off energy, and so chronic elevations would contribute to fat gain. However, this certainly doesn't imply a superiority of low-carb diets, ipso facto, especially since higher-carb plans seem to result in lower rather than higher fasting insulin.

Chris




JJ said...

Yes Chris, our data help explain how obesity happens, but say nothing about different types of diets. This all remains to be studied in our model and others that are carefully controlled.

JJ said...

Our data suggest that circulating hyperinsulinemia may make white fat "too white" (i.e. not brown enough). Remember, this is isolating the effect of circulating insulin from the pancreas. We are still investigating what brain insulin does. I'm sure the readers of this and other blogs will be interesting

LeonRover said...

JJ

'circulating hyperinsulinemia may make white fat "too white" '

Hmm, UCPs downregulated by higher basal insulin ??
That IS an elegant, integrating hypothesis. I like it: it 'tickles' my NAcc.

So guys, all together now, sing: "Don'cha make my brown fat, white" to this tune - http://www.youtube.com/watch?v=t0aT0GXW8jw

Enjoy the Solistice

Elyse McReynolds said...

I'm curious to know if there are any studies on an appropriate fat/carb ratio? In general the theory is that combining high amounts of carbs and fat in the same meal can lead to fat gain and health/digestive issues. I know there isn't a magic number, but is there a general idea that, for example, if you are eating 120G potato carbs you shouldn't have more than 30G fat?

marchwinds said...

The potato was the staple of the Irish diet for a long time. My grandfather, who was born and raised in Quebec (in the mountains north of Qc City), often had nothing else to eat as a child. My mother and her siblings were raised on a diet that contained a lot of potatoes, grown on their farm. Even now, my Mum says she doesn't feel right if she doesn't eat potatoes several times a week. It might be interesting to look at the role of potatoes among the Irish and the Irish diaspora. I am always skeptical of arguments that suggest potatoes have no nutritional value, since they played such a big role in the survival of my ancestors. Without them, I would not be here!

Stephan Guyenet said...

Hi Luis,

Thanks for sharing your experience, that is really interesting.

Hi Texasmax,

Yes, I think you could think of other foods or simple food combinations that could fulfill those criteria. Rice, beans and steamed vegetables for example. Or plain lean meat, plain sweet potatoes, and steamed vegetables.

Hi DH,

Happy holidays to you too! It never ceases to amaze me how aggressive people become when their personal identity is challenged.

Hi Chris and Dr. Johnson,

As Dr. Johnson said, the mice exhibited uncoupling in white adipose tissue. Unfortunately mice are much better at uncoupling than humans and there's currently no indication that this sort of mechanism is possible in humans. The mice were hyperglycemic early in life but this subsided later in life due to some unknown metabolic adaptation.

Dr. Johnson mentioned that the experiments I cited previously to demonstrate that hyperinsulinemia is not required for fat gain were short-term. My response is that they were plenty long enough for the development of dietary obesity (150% increase in fat mass), and 12 weeks represents ~12 percent of a mouse's natural lifespan. For a human that would represent ~9 years of life. Not a precise analogy but I think you get the point.

We do obesity studies in my lab that are as short as two weeks. A rat can double fat mass in that time if you pair a susceptible strain with the right diet. You could certainly call that short term, but I wouldn't call 12 weeks short term. It's not clear what kind of metabolic adaptation occurred in Dr. Johnson's mice in the long term-- they were initially hyperglycemic but this mysteriously disappeared.

Mark Kislich said...

Heya highly interesting blog here, glad I found it!

One thing I'm wondering is what about the low protein in such a diet, though it's complete?

I'm well aware we don't need nearly as much protein as the food industry would have us believe, and yet: what about performance?

If you're an athlete I'm sure protein requirements are somewhat on the higher side and the question is: would a potato only diet be adequate to cover protein needs?
I personally doubt it.

Yet this has made me curious and I just might experiment with a modified potato diet in the new year: some coconut oil and some eggs added should do the trick: both provide very high satiety as well, and then you DEFINITELY have all your bases covered!

Thanks Luis,

Mark

Chris Wilson said...

Hi Stephan, thanks for your followup! I'm no expert in this area, but I do agree with you that it seems this experiment may have demonstrated something that is not necessarily generalizable (e.g. to animals that do not express uncoupling proteins as readily). The sense I'm getting from it, and what Dr. Johnson has had to say, is that insulin signaling is certainly complicated- with inter-species variability.
But I still feel that it is probably not involved in a central fashion in regulating fat mass, except that it is necessary proximally for energy balance into and out of adipose (and other) tissue. I'm not impressed by the evidence that targeting insulin levels specifically (fasting or post-prandial) is necessary or effective for weight loss in humans, which it seems would be the ultimate benchmark for its role in fat mass regulation. It still seems the bulk of evidence suggests that fasting insulin rises in response to insulin resistance which is correlated with obesity but not really a causal driver.

Chris

Jane said...

Stephan, could I ask you please, why do you think induction of UCP1 in white adipose tissue can happen in mice but not in humans? Have the relevant experiments been done?

If our white fat can express UCP1, it ought to be able to keep us warm. I am now able to keep my body warm in a way I would have thought impossible. This winter I have not used my gas fire (I have no other heating) and one evening my flat was below 7 degrees C. I just put a lot of clothes on. In the old days, I couldn't do that because I'd overheat. Something is very different now.

The point is that it took 30 years of a 100%-whole-food low-meat diet to get to this point. My hunger went immediately, and my energy went up at once too. No more chronic fatigue, no more battles with weight gain. My cold tolerance did go up, but nothing compared to now.

Jane said...

Oh I forgot. In case Jim is reading this: I do intermittent fasting. Breakfast and supper and nothing except water in between.

_lemongrass_ said...

It's very interesting to read all the latest developments on eating potatoes here, on Mark's Daily Apple, and even on some low carb forums. I've been following the diet recommended by Dr. John McDougall for a number of years which is a starch-based diet (my main starch is potatoes), and I have had very good results with losing weight, maintaining a healthy low BMI, and having good energy and endurance. I never thought I'd see the day when those on the paleo and/or low-carb side of things were singing the praises of the lowly potato. Will wonders never cease?

arjay001 said...

I have to try this, Thanks for a great post!

Alice said...

Have any of you read "The Starch Solution" by Dr. McDougall? I've been trying to stick to that program, but not working as well for me as the traditional "low-carb, hi-protien" diet. I have digestive issues with meat and dairy, so I'm trying hard, but need to lose weight too. Any suggestions?

Rex said...

Just finished reading the Starch Solution myself, loved it. I'm in a different boat though, skinny guy trying to gain weight.

We're all slightly different...you sound like you would be best served going 100% vegan for a few weeks. No oils, nuts, dairy or animals products. Just fill half your plate with potatoes and the other half with veggies and eat watery fruit in between. You'll lose guaranteed. To eat 2000 calories of potatoes you would have to eat 5 pounds! I would barf way before that happened...Good luck...

Boiling Pot said...

I recall reading many years ago that weight loss and fundamental healing occur not by the one diet or the other, but by the lurching back and forth between opposing-type diets. Lots of mainly protein followed by lots of mainly carb and keep doing that. It makes the body "shake" and return to a state of normalcy.

Will said...

Okay, a more recent story. In July I started eating plant based, a lot of potatoes but no fat from meat, dairy, cheese or oil. Mashed potatoes with no fat gravy, baked fries, etc. this is from The Starch Solution.

I've lost 20 lbs so far. I'm 6' and went from 206 to 188 lbs but have gained muscle from doing weights once every 5 days, like chin-ups, dips, push-ups, etc with body weight. I sit a lot practicing guitar and computer programming.

Potatoes are so filling which is key. This totally debunks the Paleo low carbers. When you think about it fat is easily stored in the body as fat, carbs are used for energy in the muscles. Not to mention the Asians and others who eat mostly rice and veggies and weren't fat. Yeah there were a few remote tribes who ate meat but they only lived into their 40s and we're found to have heart disease. All the low carb gurus are fat from Sally Fallon, Barry Sears, William Davis to Atkins who is dead from a stroke btw.

Stephan Guyenet said...

Hi Will,

Thanks for posting your results, they don't surprise me.

However, you seem to have swallowed quite a bit of nonsense propaganda along with the useful information. LC gurus are definitely not all fat, and Atkins didn't die of a stroke.

Sally Fallon is also not a LC guru. She invited me to speak at 2010 Wise Traditions specifically to debunk the (ridiculous) idea that all healthy traditional cultures were low-carb.

sereez said...

Dear Stephan
I am very confused. I put several types of info into nutrition sites and do not understand the results
Using 100 grams as the amount for all calculations, [figures rounded up or down to closest whole number to make it easier.]
I see that 100g of raw potato, flesh and skin, contains 18g carbs, 2g fiber, 15g starch and 1g sugar . But 100g potato boiled with or without skin contains 20g carbs, almost 2g fiber, NO STARCH, and 1g sugar. So, where –did – the –starch- go? Into the boiling water? Also, I noted that the PEELED RAW WEIGHT increased by 18% after cooking: so has water been absorbed? This was true for several times that I checked. How then can one possibly calculate calories? And are these facts true of baked potatoes too? Does cutting them in half to expose the flesh make any difference to boiling or baking them? Also, are the nutrients from the skin absorbed by the flesh of the potato during boiling and/or baking, or only absorbed if we actually eat the skin? Utterly confused – thanks! [no, I'm not doing a potato diet but I am very very curious about this].