One Potato, Two Potato …

      81 Comments on One Potato, Two Potato …

Several readers sent me links today to various articles about a new study that blames potatoes for making us fat.  Here are the headlines with some quotes:

Potatoes can add plenty to waistline

Consuming an extra helping of potatoes each day — French fried, baked or otherwise — can add an average of 0.8 of a pound to body weight per year, researchers find. Over time, that can result in substantial weight gain.

Potatoes bad, nuts good for staying slim, Harvard study finds

Everyone knows that people who chow down on french fries, chug soda and go heavy on red meat tend to pile on more pounds than those who stick to salads, fruits and grains.

But is a serving of boiled potatoes really much worse than a helping of nuts? Is some white bread as bad as a candy bar? Could yogurt be a key to staying slim?

The answer to all those questions is yes, according to the provocative revelations produced by a big Harvard project that for the first time details how much weight individual foods make people put on or keep off.

Chips, Fries, Soda Most to Blame for Long-Term Weight Gain

The edict to eat less and exercise more is far from far-reaching, as a new analysis points to the increased consumption of potato chips, French fries, sugary sodas and red meat as a major cause of weight gain in people across the United States.

I have mixed feelings about the media coverage of this study.  It’s encouraging to see something other than sugar or fat getting the blame for all our ills:

The problem, said study coauthor Dr. Walter Willett, chairman of the nutrition department at the Harvard School of Public Health, is that “we don’t eat potatoes raw, so it’s easier [for the body] to transform the starch to glucose.”

Since spuds prompt a quick increase in blood sugar levels, they cause the pancreas to go into overdrive trying to bring levels back down to normal. As blood sugar spirals down, people usually experience hunger, which leads to snacking. Over many years, this cycle can result in drastic weight gain and a fatigued pancreas, possibly contributing to the development of Type 2 diabetes.

It’s also encouraging to see the message getting out that weight loss isn’t as simple as counting calories:

The findings add to the growing body of evidence that getting heavier is not just a matter of “calories in, calories out,” and that the mantra: “Eat less and exercise more” is far too simplistic. Although calories remain crucial, some foods clearly cause people to put on more weight than others, perhaps because of their chemical makeup and how our bodies process them. This understanding may help explain the dizzying, often seemingly contradictory nutritional advice from one dietary study to the next.

“Our take-home message is what you eat affects how much you eat,” Mozaffarian said. “It’s not just a blanket message about reducing everything. Each individual lifestyle factor has a pretty small effect by itself, but the combined effect can explain that gradual weight gain.”

That’s why I don’t eat potatoes anymore, in spite of dire warnings from strange people who seem emotionally invested in convincing me I’m in mortal danger of permanently losing my tolerance for them:  starches ramp up my appetite, period.  They also spike my blood sugar.  That may not happen to everyone, but it sure happens to me.

So I’m happy to see media articles warning people about consuming chips, fries,  and other glucose-bombs.  On the other hand, the study itself isn’t exactly what I’d call strong evidence.  The researchers extracted their data from three large, multi-year observational studies.  We all know what that means:  food-recall questionnaires, which are notoriously inaccurate.

The message, at least as it’s being reported in the media, is also inconsistent.  The news stories mention a plausible mechanism for how potatoes might encourage weight gain – potatoes spike glucose, which raises insulin, which drives fat storage – but then note that red meat was also associated with weight gain, while whole grains weren’t.  If insulin-spiking potatoes are fattening, why isn’t insulin-spiking whole-grain bread?

Worst of all (though hardly surprising), the study is being reported as if the researchers have pinpointed cause and effect:

The researchers did find other culprits. For each additional sugary soft drink consumed per day, participants in the study gained an average of 1 pound over four years. Extra servings of red meats and processed meats did only slightly less damage.

Meats doing damage … yup, that sounds like cause and effect to me.

“I think it’s an important study,” said Kelly D. Brownell, director of Yale University’s Rudd Center for Food Policy and Obesity, who co-wrote an accompanying article. “It’s based on a large number of people followed over time, and it shows there are particular types of food that are contributing more than others to the obesity problem — and that some are protective against weight gain.”

No, Dr. Brownell, the study merely shows that some foods were associated with weight gain and some weren’t.  We can’t conclude what’s actually protective and what isn’t from this kind of observational data.  Fortunately, one expert quoted in the media made that very point:

“To attempt to isolate the effect of specific foods on weight changes is fraught with problems,” said Lawrence J. Cheskin, who heads the Johns Hopkins Weight Management Center. “One is that people may conclude that if they simply stop eating X, they will reduce the chance of weight gain. This is unlikely, and a false conclusion. Similarly, it is likely more a result of people who eat fruit being more health-conscious than fruit per se causing less weight gain.”

Bingo.  Health-conscious people are different.  They’re more likely to exercise, more likely to get enough sleep, less likely to eat potato chips, less likely to drink sodas, and – because they’ve been warned about it for 30-plus years – less likely to eat red meat, which is probably why red meat was associated with weight gain.

Yes, I believe potatoes and sodas make insulin-resistant people fatter.  But I wouldn’t hold up this study as proof.


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81 thoughts on “One Potato, Two Potato …

  1. Roberto

    Really Sami? You blame potatoes for your weight gain because you ate McDonalds french fries twice a week? Never mind that a third of those calories are from refined, rancid vegetable oil. Did you ever wash those fries down with free refill high fructose corn syrup?

  2. cancerclasses

    Jan: Fiber is the most common cause if colon cancer. A study in the 2000 Lancet showed that people that eat the most fiber have the highest rates of colon cancer. The fiber (essentially sticks, twigs & saw dust) irritates the delicate tissues in the colon causing inflammation. The INFL causes cellular hypoxia, & as Nobel Laureate M.D., PhD biochemist Otto Warburg proved in 1928, just a 35% reduction of oxygen flow into the cell causes them to either die (which on a large enough scale causes tissue necrosis & tissue death), or the stronger cells switch to glycolysis, fermentation of sugars to produce energy & thus become cancer.

    Contrary to the conventional wisdom, fiber is bad news. For the no bullcrap truth about cancer get & read THE HIDDEN STORY OF CANCER. http://goo.gl/96Wvn

    http://goo.gl/96Wvn

  3. Jan

    @Debbie – Some processed meats are fine – the ham and bacon we get from our pastured hogs are only cured with salt and some spices, then cold smoked. However, when I got to buy lunch meat for my teenage son, I have to buy Applegate Organic brand because the mainstream brands, like Butterball and Oscar Meyer, add things like potato starch, corn starch, high fructose corn syrup, soy isolates and MSG in theirs. Lots of breakfast sausages, hot dogs and bratwurst are often loaded with HFCS and soy or starch fillers, and even most commercial brands of bacon contain sugar.

  4. Nowhereman

    “And it’s not as if they go around measuring weight and body fat on the thousands of participants. This is all questionnaire data, which I don’t trust.”

    Bingo, Tom! That’s the problem with most of these kinds of studies. It’s not like the researchers are bringing in hundreds of participants in at least once a week for several years and doing proper measurements before, during, and after the study, no matter how long it went on. This is at it’s core, a simple observational type study. A real clinical or experimental study would put multiple groups under close observation while controlling what the participants ate and when to see what would happen. A good study would seperate the meats, seperate the fats, seperate the starches, the grains, and and some groups would be seperated into various degrees of exercise.

    Furthermore, as you point out, the whole thing about questionaire observational studies is that they rely solely on the participants being honest about what they eat and do. Without controls, there is no way to be sure what the participants say is even the whole truth and nothing but the truth.

    So as another poster here pointed out, the observational studies are good for getting an idea of where to go in developing a hypothesis, but they are being treated as the end all and be all as gospel, when the next step is detailed clinicals.

    And that gets to another point; what can we do to change this mentality? It’s obviously not going to be simple in dismantling decades of special interest groups and big money lobbies. Do we really have to plod along through a “Dark Age” of nutritional advice?

    I don’t mind if they keep doing observational studies, since large clinical studies are hugely expensive. I just want the researchers and the media who report on them to make it clear how limited these studies are.

  5. Brad C. Hodson

    There they go, lumping in red meat again. Since dumping grains, I’ve made sure to eat AT LEAST one serving of (preferably grain fed) red meat per day. I’ve lost nearly forty pounds of pure blubber in 4 months. Guess I better go back to those healthy whole grains instead so I don’t gain it back…

    And yogurt, according to the study.

  6. Charlie

    The problem is even if you got normal response to potatoes and other carbs bombs and you have no weight problem is how long will your insulin producing metabolism is going to last having to process so much starch.

    In my opinion people make a mistake of comparing other civilizations consumption of thinks like potatoes and rice without taking into account amount of energy expenditure. Maybe potatoes and rice can be ok if you live a very active live, with a lot of hard work. But for the modern sedentary life style is they are not a good diet to copy.

    New study modest carb reduction, increase in fat, lowers deep body fat.

    http://www.sciencedaily.com/releases/2011/06/110606092532.htm

    Thanks for the link. I’m going to look up that study.

  7. Firebird

    We have to keep in mind that while weight loss is great, it is not the tell tale sign of how our internal health is. You could eat potatoes all day long and maintain a svelte figure, but that doesn’t mean that it isn’t causing problems. I turn to skinny as a rail Hall of Fame hockey player Bobby Clarke, who is a life long diabetic. No weight problem, but terribly unhealthy internally. The mirror doesn’t tell all.

    I’ve seen that in my own family: skinny people who become type 2 diabetics.

  8. Underground

    But, but, but… everyone KNOWS that red meat leads to weight gain, colon cancer, and kicking babies. While potatos are just innocent, healthy vegetables, that are at the top of the nutrition scale as the industry rep pointed out. Not mentioning that something can be nutritious and still be unhealthy in some respect.

    It’s like they talked around the subject that was right in front of them, trying to find ANYTHING to blame except what was right in front of their face. An *extra* serving of potato? Surely it’s not related to volume, it must be the meat.

  9. Charlie

    The problem is even if you got normal response to potatoes and other carbs bombs and you have no weight problem is how long will your insulin producing metabolism is going to last having to process so much starch.

    In my opinion people make a mistake of comparing other civilizations consumption of thinks like potatoes and rice without taking into account amount of energy expenditure. Maybe potatoes and rice can be ok if you live a very active live, with a lot of hard work. But for the modern sedentary life style is they are not a good diet to copy.

    New study modest carb reduction, increase in fat, lowers deep body fat.

    http://www.sciencedaily.com/releases/2011/06/110606092532.htm

    Thanks for the link. I’m going to look up that study.

  10. Firebird

    We have to keep in mind that while weight loss is great, it is not the tell tale sign of how our internal health is. You could eat potatoes all day long and maintain a svelte figure, but that doesn’t mean that it isn’t causing problems. I turn to skinny as a rail Hall of Fame hockey player Bobby Clarke, who is a life long diabetic. No weight problem, but terribly unhealthy internally. The mirror doesn’t tell all.

    I’ve seen that in my own family: skinny people who become type 2 diabetics.

  11. Underground

    But, but, but… everyone KNOWS that red meat leads to weight gain, colon cancer, and kicking babies. While potatos are just innocent, healthy vegetables, that are at the top of the nutrition scale as the industry rep pointed out. Not mentioning that something can be nutritious and still be unhealthy in some respect.

    It’s like they talked around the subject that was right in front of them, trying to find ANYTHING to blame except what was right in front of their face. An *extra* serving of potato? Surely it’s not related to volume, it must be the meat.

  12. fredt

    Thirty some comments and no one has mentioned Chris Voigt at http://www.20potatoesaday.com/

    I personally can only tolerate about 120 gm of boiled, baked or pan fried potatoes. (about 100 C) Anything more and my 1 hour blood glucose goes to high. Mashed, or other methods, I can can tolerate perhaps 60 grams. It seems to have to do with the speed of gluose release.

    Also 100 C of potatoes is not much. I am not a athlete nor do I do physical labor, so I can get by on a few carbs.

    Tom, keep up the fine work. You are making a difference in this tough battle of re-educating humanity.

    Yeah, I remember when his story hit the news. I’d go into glucose shock if I tried his experiment.

  13. Zubious

    I’m with Theo on this one – I know plenty of people who regularly eat a variation of potatoes (sweet variaion, russet, etc) and they are lean. Even I do fried – just not in canola, or any “vegetable” oil. Beef tallow or coconut oil for me.

    Either event, I wonder if the results might be different if they used beef tallow to fry like the old days, instead of these crazy oils.

    I don’t think everyone has to avoid potatoes. It’s a matter of how you react to them. I don’t react well at all.

  14. John Newlin

    I eat a ton of carbs when I’m exercising, on a 5 hour bike ride, those potatoes are like little magical balls of energy.

  15. Marilyn

    I eat potatoes regularly, as well as rice. But the serving sizes are always small, and they’re always prepared with butter or cream/sour cream or meat drippings. Dinner is often meat (including lots of red meat), a small serving of potato or rice, and a lettuce/tomato/blue cheese salad with olive oil. Other veggies occasionally, fruit rarely, sugared drinks and fruit juices never. So far, everybody happy.

    If the old food-groups guide put out by the government in the 1940s is any indication (which it may not be), that’s what people used to do. The guide called for one serving of grains and one serving of potatoes per day.

  16. fredt

    Thirty some comments and no one has mentioned Chris Voigt at http://www.20potatoesaday.com/

    I personally can only tolerate about 120 gm of boiled, baked or pan fried potatoes. (about 100 C) Anything more and my 1 hour blood glucose goes to high. Mashed, or other methods, I can can tolerate perhaps 60 grams. It seems to have to do with the speed of gluose release.

    Also 100 C of potatoes is not much. I am not a athlete nor do I do physical labor, so I can get by on a few carbs.

    Tom, keep up the fine work. You are making a difference in this tough battle of re-educating humanity.

    Yeah, I remember when his story hit the news. I’d go into glucose shock if I tried his experiment.

  17. Zubious

    I’m with Theo on this one – I know plenty of people who regularly eat a variation of potatoes (sweet variaion, russet, etc) and they are lean. Even I do fried – just not in canola, or any “vegetable” oil. Beef tallow or coconut oil for me.

    Either event, I wonder if the results might be different if they used beef tallow to fry like the old days, instead of these crazy oils.

    I don’t think everyone has to avoid potatoes. It’s a matter of how you react to them. I don’t react well at all.

  18. John Newlin

    I eat a ton of carbs when I’m exercising, on a 5 hour bike ride, those potatoes are like little magical balls of energy.

  19. Marilyn

    I eat potatoes regularly, as well as rice. But the serving sizes are always small, and they’re always prepared with butter or cream/sour cream or meat drippings. Dinner is often meat (including lots of red meat), a small serving of potato or rice, and a lettuce/tomato/blue cheese salad with olive oil. Other veggies occasionally, fruit rarely, sugared drinks and fruit juices never. So far, everybody happy.

    If the old food-groups guide put out by the government in the 1940s is any indication (which it may not be), that’s what people used to do. The guide called for one serving of grains and one serving of potatoes per day.

  20. WSB

    Skinny diabetics aren’t that uncommon (approximately 10% of all T2’s); there seems to be a relationship with food intolerance(s), specifically gluten and casein.

    I think this may be part of the problem with the Kwasniewski diet – it is not gluten free. This study shows a higher mortality rate for non celiac gluten sensitivty (aka “just sensitive”) vs celiacs.
    http://www.celiac.com/articles/21905/1/Gluten-Sensitivity-Celiac-Disease-Carry-Higher-Mortality-Risk/Page1.html

    Plan your cheat meals carefully!

  21. WSB

    Skinny diabetics aren’t that uncommon (approximately 10% of all T2’s); there seems to be a relationship with food intolerance(s), specifically gluten and casein.

    I think this may be part of the problem with the Kwasniewski diet – it is not gluten free. This study shows a higher mortality rate for non celiac gluten sensitivty (aka “just sensitive”) vs celiacs.
    http://www.celiac.com/articles/21905/1/Gluten-Sensitivity-Celiac-Disease-Carry-Higher-Mortality-Risk/Page1.html

    Plan your cheat meals carefully!

  22. Drew

    In debating the whole food/paleo/low carb diet issues, I noticed how some items like watermelons, and potatoes don’t necessarily fit in. Potatoes seem to be a BIG issue for many people but I wonder if this may come down to portions, preparation and how people eat them. ‘
    Eating a small potato with butter with steak and milk over an hour and making certain to chew it all is not going to result in the same problems, as eating a larger order of fries cooked in vegetable oil and served with a tall order of Mountain Dew and eaten in 15 minutes. This is only made worst when people buy pretzels and pop from a vending machine because they have no time to sit down and eat properly.

    Portions and preparation matter, of course. But for some of us, even small portions jack up blood sugar.

  23. Drew

    In debating the whole food/paleo/low carb diet issues, I noticed how some items like watermelons, and potatoes don’t necessarily fit in. Potatoes seem to be a BIG issue for many people but I wonder if this may come down to portions, preparation and how people eat them. ‘
    Eating a small potato with butter with steak and milk over an hour and making certain to chew it all is not going to result in the same problems, as eating a larger order of fries cooked in vegetable oil and served with a tall order of Mountain Dew and eaten in 15 minutes. This is only made worst when people buy pretzels and pop from a vending machine because they have no time to sit down and eat properly.

    Portions and preparation matter, of course. But for some of us, even small portions jack up blood sugar.

  24. BW

    I see you mentioning various carbs spiking your blood sugar, I’m guessing you are using a blood glucose meter? Is that something that would be appropriate for your average joe as a way to see how they react to various carb sources?

    It seems simple, and the meters (and test strips if you don’t get what I’d call “scam” brands) are relatively cheap. However oftentimes things appear simple that are not, which is why I’m posing this question.

    Thanks for the great blog and Movie… I wish I could get our in-house “health” program people to stop parroting the health insurance reps…. I’ve tried and they listen to the ‘experts’.. who of course have no conflict of interest…yeah..that’s it..

    Yes, I’m talking about a glucose meter you can pick up at any drug store.

  25. BW

    I see you mentioning various carbs spiking your blood sugar, I’m guessing you are using a blood glucose meter? Is that something that would be appropriate for your average joe as a way to see how they react to various carb sources?

    It seems simple, and the meters (and test strips if you don’t get what I’d call “scam” brands) are relatively cheap. However oftentimes things appear simple that are not, which is why I’m posing this question.

    Thanks for the great blog and Movie… I wish I could get our in-house “health” program people to stop parroting the health insurance reps…. I’ve tried and they listen to the ‘experts’.. who of course have no conflict of interest…yeah..that’s it..

    Yes, I’m talking about a glucose meter you can pick up at any drug store.

  26. Lauren

    So are potatoes really so bad? I ask because my husband (whom I have recently forced low-carb upon) really isn’t doing so well 4 weeks in. I know for me that I feel 10x better and have energy all day if I have a fig with my steak for breakfast, while a high fat/mod protein breakfast will leave me sluggish, sleepy and hungry in a few hours. My husband hates fruit, but I was thinking of making him a baked potato for his breakfast/lunch tomorrow. I’ll scoop out a fair amount of the starch and load the thing up with mushrooms, onions, cheese, bacon, brisket, butter… you get the idea. What do you think?

    It could just be that your husband is going through an adjustment period as his body is retrained to burn more fat and less glucose. If he really can’t stand it, I’d add a few carbs (not sugar or grains) back into his diet and see if it helps. But if he eats a potato, I’d check his blood sugar an hour later to see if it causes a big spike.

  27. Lauren

    So are potatoes really so bad? I ask because my husband (whom I have recently forced low-carb upon) really isn’t doing so well 4 weeks in. I know for me that I feel 10x better and have energy all day if I have a fig with my steak for breakfast, while a high fat/mod protein breakfast will leave me sluggish, sleepy and hungry in a few hours. My husband hates fruit, but I was thinking of making him a baked potato for his breakfast/lunch tomorrow. I’ll scoop out a fair amount of the starch and load the thing up with mushrooms, onions, cheese, bacon, brisket, butter… you get the idea. What do you think?

    It could just be that your husband is going through an adjustment period as his body is retrained to burn more fat and less glucose. If he really can’t stand it, I’d add a few carbs (not sugar or grains) back into his diet and see if it helps. But if he eats a potato, I’d check his blood sugar an hour later to see if it causes a big spike.

  28. Ray

    Mitt Romney says in his book “No Apology: The Case for American Greatness” (p. 6) that one year his Dad’s family in Idaho “lived on nothing but potatoes — for breakfast, lunch and dinner.” Is that even possible?

    Yes, but I wouldn’t recommend it.

  29. Ray

    Mitt Romney says in his book “No Apology: The Case for American Greatness” (p. 6) that one year his Dad’s family in Idaho “lived on nothing but potatoes — for breakfast, lunch and dinner.” Is that even possible?

    Yes, but I wouldn’t recommend it.

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