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Jun 22, 2011 10:16 PM

Eating potato products makes you ... (wait for it) ... FAT!

Well, ok, not quite.

But according to a Harvard study, there is a strong correlation between consumption of potatoes to weight gain.

From the WSJ:

"Eating more potato chips and French fries is likely to lead to a bigger weight gain over the years than the weight change associated with eating more of other foods, new research indicates.

The study, from the New England Journal of Medicine, stands out because it quantifies how much weight a person is likely to gain or lose over four years based on one additional daily serving of a range of specific foods. Eating more potatoes correlated with a gain of 1.28 pounds, with French fries in particular associated with a 3.35-pound gain."


Full article here:

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  1. Wow, what an earth-shattering study. Next thing you know, they will be telling us that caffeine consumed before bedtime can cause insomnia and that sugar can (gasp) cause cavities in addition to weight gain.

    Glad to know the Harvard folks are hard at work, cranking out ground-breaking new research.

    26 Replies
    1. re: jlhinwa

      Please don't mock, this is actually important research, baseline research is always the most mocked and always the most essential in terms of being done. If potatoes are uniquely fattening in comparison to other tubers then that is something we should understand better.

      And consider that extra consumption of just french fries over a four year period leads to a 3.3lb gain. It's not hard to extrapolate that to forty years and see that french fries could lead to thirty excess pounds.

      In any event, of course potatoes are fattening, they induce an elevated insulin response, and since insulin is the hormone responsible for storing fatty acids in fat cells, foods that induce more insulin response tend to be fattening as a rule. it's just basic science.

      1. re: jadekarrde

        but right there is the statement that it's not uniquely potatoes.

        Potato chips are deep-fried. French fries are deep-fried. It's the *fat*, not the potatoes themselves!

        *anything* will cause weight gain if it's deep fried!

        Let's see this "study" repeated with baked potatoes, hmmm?

        1. re: sunshine842

          From the LA Times report, Even boiled potatoes add weight!

          1. re: mnosyne

            Okay, but let's get to the point -- if you eat EXTRA calories above your normal daily consumption, you're going to gain weight, no matter whether those calories come from lettuce, potatoes, or chocolate fudge.

            EXTRA calories=EXTRA weight

            And did those boiled potatoes come swimming in butter and sour cream (betting it's a yes).

            1. re: sunshine842

              I doubt it, sunshine842. If it's a scientific study you can be sure that each food item was carefully controlled. Obviously butter and sour cream would completely change the outcome of the study. Scientific method requires controlling for variables like that.

              1. re: Kitchen Imp

                Except the data for this study was collected of 12-20 year periods, and was largely based on self reporting. The nurses and other health professionals participating in the study were not locked up in a lab and fed controlled portions. Tightly controlled studies only use college student volunteers for short periods of time.

                "The study has some limitations, including that it relied on self-reports of portion size and used different serving sizes between foods.

                Read more:"

                I think this site gives a better description of the underlying studies

                The study reported in the news this week is just one of many that have pulled information from NHS NHS2 etc.

                1. re: paulj

                  Interesting - and thank you for posting the links. Still, even with the caveat about self-reporting, it's very hard for me to imagine that the researchers who wrote up the study were quite as naive as sunshine842's comment seems to suggest...

                  1. re: Kitchen Imp

                    That's why we need to know more about the methodology of the underlying studies (which are probably reported in a number of other places), and details of this study. The details are in the paper, not in the abstract or news summaries.

                    1. re: Kitchen Imp

                      No, if you read the WSJ article, it appears that not much was controled. Unless the article is just poorly written, all they looked at was "servings" not total calories. So we could hypothesize that people who added a "serving" of french fries to their diet may have averaged an extra 500 calories whereas the cake people only ate 400. Just no way to know as I read it.

                      And to the person above who mentioned boiled potatoes, the potatoes mentioned in this study were either french fries or potato chips.

                      I read the article this weekend before I saw this thread. At the time I thought I had just wasted 2 minutes of my was pretty worthless. And I say that even though I love the WSJ, love cake, and don't eat french the message certainly appealed to me...i hate to poke holes in it ;-)

                  2. re: Kitchen Imp

                    like controlling for deep-fried?

                    Potatoes are typically accept to provide about 60 calories per 100 grams.

                    Oils (regardless of type) provide about 900 calories per 100 grams.

                    While eating fat in and of itself doesn't make you fat, fat is an enormously calorie-dense food, and it doesn't take much fat to stuff an extra few hundred (or even thousand!) calories a day into your diet -- and unless you have enough physical activity to expend that additional intake, you WILL get....fat.

              2. re: sunshine842

                No, evidently it's more the potato itself than the fat. This is not really all that new of a finding, as other research has been done prior to this.
                I listened to an interview today with one of the people involved in the Harvard study and he was _very_ specific to point out something that I've heard mentioned before by other medical folks: eating fat doesn't necessarily make you fat. It may contribute to other problems if too much is consumed, but is definitely _not_ the biggest culprit in weight gain. The study actually indicated that there can be instances where the fat content of certain foods actually prevented or slowed down weight gain.

                Bogttom line: enjoy _anything_ in moderation...that's one thing that every study agrees upon. And it makes the most sense in the end, too.

              3. re: jadekarrde

                No offense intended by my mocking reply. I stand by my sentiment that no matter how thorough the research, how well-intentioned the study, etc., it is lots of $$ being spent to point out the obvious.

                At the end of the day, weight gain and loss is a simple mathematical formula. More calories consumed than burned = weight gain, more calories burned than consumed = weight loss. At a time when there are lots of people in our country that are undernourished, I would rather see the money spent on this kind of thing going directly to providing people with nutritious food.

                We have known for how many decades that smoking causes cancer. And yet people continue to light up. We have a generation of kids that grew up in an era when smoking was not popular and who have non-smoking parents, yet they still start smoking and get hooked.

                1. re: jlhinwa

                  Fair enough, but I think this study might actually be relevant to the issue of the undernourished. One of the things the study shows is exactly that there isn't always "a simple mathematical formula" between calories and weight gain. instead, weight gain is disproportionately large per serving of potatoes than it is for similar servings of other foods. Given that we have so many urban "food deserts" where people rely on foods like potatoes as a major staple of their diet (since that's all the fast-food place on the corner carries), it's critical to have solid data on the health consequences of eating them.

                  I'm sure there are posts on some board already about food deserts, but just in case -

                  1. re: jlhinwa

                    "We have known for how many decades that smoking causes cancer. And yet people continue to light up. We have a generation of kids that grew up in an era when smoking was not popular and who have non-smoking parents, yet they still start smoking and get hooked."

                    True. But at one time, this was not common knowledge. It seems obvious now, but people used to scoff at the idea that smoking was unhealthy. And though it's true that some young people still start smoking and get hooked, rates of smoking have consistently declined in the US over the past 40 years. Not only are fewer people smoking, but those who do smoke are going through fewer packs than people did a generation ago.

                    I haven't looked at the methodology of this potato-consumption study, and I'm generally skeptical of nutritional studies based on self-report. However, although the investigators presumably started with a specific hypothesis, they didn't know whether the data would support it. That's the whole point of doing science -- to find evidence that supports or refutes your hypothesis. This particular study may be "pointing out the obvious," but sometimes things that are obvious common knowledge turn out to be untrue.

                    1. re: jlhinwa

                      The wsj synposis in the OP of the study was inaccurate. The Washington Post's story was much more inclusive and what the study showed is that it's NOT a simple mathematical formula of calories in and calories out. Different types of foods cause different weight gain/loss. It's against the whole CW that 3500 calories = 1 lb that currently being touted. Eating the same number of calories in nuts does not cause the same weight gain as eating french fries.The study has its problems as people have pointed out but I believe in the bases of it which is all calories are not created equal as weight goes. And, diverting people to the right foods can make a big difference (speaking in part from personal experience).


                      1. re: chowser

                        It's *always* been about making the right choices....whether that's eating boiled or fried potatoes, or flipping on the latest episode of House versus getting off your butt and taking a walk around the block.

                        1. re: sunshine842

                          But, what are the "right" choices when it comes to food? Ask any CH and you'll get a wide variety of responses from the avid meat eater to the vegan. For decades, we've been told a calorie is a calorie. And, now they're saying it might not be so. According to the study, it's not as intuitive as you'd think.

                          1. re: chowser

                            sorry, but this one is going to have to be repeated in a double-blind, peer-reviewed study (like actual research) for me to buy off on it.

                            1. re: sunshine842

                              Which will never happen, because you can't do long-term nutritional studies like that.

                              1. re: jlafler

                                My point being that you need something more structured than self-reporting and flaky abstracts to convince the skeptics.

                                1. re: sunshine842

                                  Well, as I said above, I'm generally skeptical of nutritional studies based on self-reporting. But double-blinded studies are really only possible with things like drugs, for which you can control with a placebo -- the equivalent in this case would be to feed one group of people potatoes, and the other group something that looked, smelled, and tasted exactly like a potato, but wasn't a potato. In other words, impossible.

                                  There are all sorts of factors that make nutrition studies difficult, especially long-term studies: accurately assessing what people are eating is hard to do outside of a laboratory; controlling for all the possible cofactors is virtually impossible. The only really good model for a long-term nutritional study that I know of is gathering data on an isolated population of people eating a consistent diet, and then looking at what happens to them when that diet is changed. And here you run into problems because changes in diet of generally occur at the same time as other social and cultural changes; also, an isolated population will have a lot less genetic variation than the general population.

                                  1. re: jlafler

                                    Thanks for adding that well thought out response (although given your background, it might not take as much thought as it would take me). People aren't human guinea pigs, or drosophila for that matter, and no one is going to stand for being completely monitored, for a decade, let alone trying to find thousands who will do it. But, that doesn't mean every study involving people is meaningless.

                                    My feeling is with studies is that, even if it were double blind, peer reviewed, it never stands for the whole population anyway. In cases like these, we, as individuals, can test it out on our own bodies and see if it works for us, if we're interested. I know, personally, having weighed/measured/journaled my food food intake, I've lost weight eating more calories, on something like the Perricone diet, a little lower in carbs but all healthy foods (salmon, steel cut oatmeal, blueberries, nuts). If it works for me, I don't need a peer reviewed studies that show it does. Maybe it's the placebo affect (though I doubt it because I used the diet for it's supposedly anti-wrinkle effect, not weight loss--though I saw no difference in the wrinkle factor) but if it works, it works.

                                    1. re: jlafler

                                      Sometimes an experiment is set up to test a particular hypothesis. In other cases, scientists take data collected as part of another experiment or project, and test their own hypothesis. The subject matter of this thread is of the second type. They are working with data that has been collected over many years others, data that deals with more than just diet.

                                      Scientific papers are often valued more for the questions that they raise than for the questions they settle. A well written paper will have a section near the end that suggests areas for further research.

                                      1. re: jlafler

                                        I also wanted to add that while self-reporting obviously isn't exact, with over 120,000 people studied, the variations between the food reported will level out, eg. the difference between overreporting nuts will be about the same as overreporting potato chips, as long as the population is similar. Given that a double blind test is impossible over years for this, studying 120,000 people will level out the variance, according to the Mean Value Theorem.

                        2. re: jadekarrde

                          It is not just "basic science,'" it's model building with the assumption "all other things being equal." Which we have no way of knowing

                      2. I kind of thought it was common knowledge. Years ago I remember hearing somewhere that a baked potato will elevate blood sugar faster than a Snickers bar.

                        1. I'd be more interested in the article if the information was specific - i.e. if they stated that subjects were given an extra 200 calories a day and the group that took in those calories from fruits, grains and nuts only gained a pound, versus the group that ate 200 cal of fries a day gaining 3 pounds.
                          Saving 'a serving' means little to me in the contaxt of this study - I know that if I had a 'serving' of strawberries every day, it would do little to increase or decrease my weight, as there are what, 30 calories in a half a cup? But if I had my version of a serving of fries, I'd be looking at a small bag from somewhere like McDonalds or Wendy's (sadly not in the UK, but for my sake, a good thing. I've done my own study on the weight gain caused by a 'serving' of bacon cheeseburgers in my time.) The small fries at Wendy's? 320 calories. I'd be lucky to only gain 3 pounds in a year adding that to my diet every day.

                          1 Reply
                          1. re: ultimatepotato

                            That is an excellent point, ultimatepotato. If there were something that showed potatoes or potato products added more pounds to a person per calorie consumed than another food, then that would be interesting.

                            is a better summary of this study from Science Daily, with less emphasis on potato chips.

                            It also has a link the Harvard press release, which may be the main source of the newspaper summaries. When scientific studies like this pass through several levels of journalism, the emphasis can change.

                            1. And you can be sure that Federal funding was thrown at this study. lol

                              Our tax dollars at work.

                              7 Replies
                              1. re: RedTop

                                "Supported by grants (DK46200, DK58845, HL085710, HL60712, HL35464, CA87969, CA50385, CA55075, and CA95589) from the National Institutes of Health and by the Searle Scholars Program."
                                The study was not just looking at potatoes. They looked at the long term effect of a number foods (or food categories), as well as activities (or inactivities).

                                1. re: paulj

                                  It was low hanging fruit, paul. Couldn't resist the temptation.

                                  1. re: RedTop

                                    As people who care about food I think it's important that we not mock research like this. You can be sure that if it's a Harvard study (or any study done at a reputable research institution) the research design is far, far more exacting and detailed than the newspaper will ever describe. Funding proposals go through an extraordinary number of controls, including stages of review by experts in the field, before they are given $$$, federal or otherwise. The news only will report on the part the public will immediately grab onto, not what may have been the key aims or findings of the research. Why should we presume that we know more than expert researchers and think that just because it sounds obvious to us they must be stupid? Clearly we're not getting the whole story.

                                    1. re: Kitchen Imp

                                      K I, sorry, but I'm not in your camp on this. Our Congress couches billions of dollars of our tax remittances for "pork" spending every session. And because the President does not have a Line Item Veto, very important expenditure bills have sucker addendums that ride along to approval to assure the orifinal expendature is approved. Just think about the travesty of The Bridge to Nowhere--a gift to Sen. Ted Stevens.

                                      No one in education or government needs to remind me that if I eat fat, I'll get fat. You. Me. We're not that stupid.

                                      1. re: RedTop

                                        This kind of study has nothing to do with "pork." Congress does not approve of or have any involvement in funding individual studies, nor would they ever be attached to bills. And my understanding is that this study was not about eating fat making anyone fat. It was about the rate at which the body metabolizes (breaks down) different kinds of foods and the way they contribute to weight gain. It's interesting that potatoes (even boiled) would lead to greater weight gain that other foods that have the same amount of calories. That's important primary research in the fight against obesity.

                                        1. re: RedTop

                                          Someone had to do research at some point that figured out that certain foods are higher in calories and fat than others. Our ancestors did not have the benefit of the knowledge that you seem to think is intuitive, but which in fact most often came from publicly and privately funded research. And to be sure, Congress funds politically-inspired pork, but publicly funded research sponsored by agencies like the NSF or NIH are far from it. As Kitchen Imp superbly points out above, the process by which a lot of the research funding is apportioned is incredibly rigorous, largely apolitical, and decided by a broad number of experts in the field who volunteer to review these grant proposals due to their desire to serve the research community rather than any political party. I know many people who have served as reviewers for national funding agencies (including in the sciences, humanities, and arts), and they are in no way politically motivated.

                                  2. re: RedTop

                                    Red Top,

                                    You laugh. Why? Because you think the result is, what?, so obvious?

                                    But is that really the standard we should use for scientific thought?

                                    People used to think that the Earth was the center of the universe, and then when we were disabused of that notion, we were convinced the Earth was, well you know, flat.