by Marion Nestle
Jun 26 2011

Eat French fries, gain weight?

A reader, Thibault H writes:

So Harvard University came out with a study that news reporters are saying tells us that those who tend to eat more potatoes gain x amount of weight over 10 years…What do you make of this?…could it be possible that potatoes themselves are not the culprit and rather those who tend to eat more potatoes have a fattier diet or perhaps more sedentary lifestyle.

It could indeed.  The study, which came out in the New England Journal of Medicine last week, looked at the weight gained by more than 100,000 people who had filled out diet questionnaires in 1986 or later.  It correlates what people said they ate with weight gained over periods of 4 years:

The results show that people who said they habitually ate potato chips, potatoes, or fries—as well as the the other foods in the top part of the diagram—were more likely to gain weight.

People who reported frequent eating of the foods in the lower part of the diagram were likely to have lost weight.

What fun!  The study assigns pounds of weight gained or lost to specific foods.

The study also did a more detailed analysis.  This showed that French fries were linked to the greatest weight gain: 3.35 pounds over a 4-year period.  If you habitually eat French fries, you may have a hard time controlling your weight.

No surprise.  I recently ordered a side of fries in an excellent restaurant and was floored by the size of the order Eat a small handful: no problem.  But this order surely hit 800 calories.  Fortunately, there were four of us to share it.

Here’s how I explained the study to Katherine Hobsen of the Wall Street Journal (June 23):

Marion Nestle, New York University professor of nutrition and public health, expressed surprise that potato products were linked with more weight gain than desserts like cake, cookies and doughnuts, which contribute the most calories to the American diet, other research shows. She says she suspects people who eat potato chips and fries also tend to eat too much in general, making these foods markers for a diet leading to weight gain.

The new Dietery Guidelines “policy document” has a particularly entertaining chart of the leading sources of calories in U.S. diets.  Here are the top six, in order:

  • “Grain-based” desserts (translation: cakes, pies, cookies, cupcakes, etc)
  • Breads
  • Chicken and chicken mixed dishes (translation: fingers)
  • Sodas, energy, and sports drinks
  • Pizza
  • Alcoholic beverages

Potato chips are #11 and fries are #17.

This new study provides evidence supporting what everyone surely ought to know by now: eat your veggies!

P.S.  Here’s Andy Bellatti’s take on this study.  His point: it’s not the carbs, it’s calories.




  • KB

    Can you explain how they came up with the foods that are the leading source of calories? The link just goes to the general dietary guidelines page so I can’t find the policy document. I would think that they’re a balance of the most calorically dense foods and the foods most commonly eaten but are grain-based desserts really that frequently eaten?

  • Sheila

    Thank you for illustrating a point that seems frequently lost on many people. Just because you ordered a food serving, does not mean you must single-handedly eat the entire huge pile of food delivered to you. As you indicated, a huge order of fries arrived at the table, you shared it with all 4 people at the table. You enjoyed a small portion, and did not consume the entire plate full of food.

  • NoGluten

    Fries are provided in large portions with inexpensive meals. This whole study needs to be parsed out for income levels.

  • As an aside, I’m wondering what is your take on the results for milk in that study. Specifically, why is it that skim milk had worse weight outcomes than whole milk?

  • Beth Reed

    What about the fact that chips and fries are fried and therefore have a lot of fat, is fat content considered here, as in added fat due to deep frying? Not to mention the sugar content in the desserts and sugary drinks?

  • Charlie L

    The real question is why starchy or sugary foods are associated with increased caloric intake. Why do these types of foods encourage people to eat more? The original NEJM, in the Discussion section, has a reasonable answer: “…consumption of starches and refined grains may be less satiating, increasing subsequent hunger signals and total caloric intake, as compared with equivalent numbers of calories obtained from less processed, higher-fiber foods that also contain healthy fats and protein.”

    In other words, eating satiating foods, which will tend to be non-starchy and non-sugary means that you eat less calories in the long-run. The study’s results seem to bear this out. Where the “there are no bad foods, only bad portions” mentality is deficient is that it doesn’t capture the fact that the body doesn’t treat or handle all calories equally.

    Obviously, the less calories you consume, be it from Twinkies ( or raw vegetables and everything in between, the more weight you can lose. But certain food choices seem to make it easier (and therefore more sustainable) not to increase caloric intake by satisfying hunger better and longer.

    On a related note, I think Mr. Bellatti’s post in response to this story is a few French fries short of a Happy Meal. He attacks the “infamous” Gary Taubes on the basis that he is not a scientist or nutritionist instead of focusing on any of Mr. Taubes’ actual arguments and evidence (a genetic fallacy, in logic).

  • Roxanne Rieske

    @KB, it would shock you to see how many pastries and sweets people actually eat. I have worked in the bakery business for 10 years, and there are lots of people that come in everyday for a pastry (which are large) and coffee, or a huge sugary bagel that’s 500 calories in itself, without cream cheese. What’s worse is that these things are basically empty carbs, so in two hours you have to eat again because that pastry is not sustaining. Calorie overload! That’s just in the morning! Then what happens when you have a giant cookie w/ your lunch? Mind boggling.

  • Sebastion Goodsense

    French fries are Michelle Obama’s favorite food. ‘Nuff said.

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  • Soja

    People generally know what causes weight gain and what doesn’t. I know I grew up eating hamburgers, french fries, processed meats, the entire pig/cow, kool-aid and soda with sugar, and very few vege’s, fruit, high fiber foods that are good for you. I ended up diabetic with high blood pressure. I had to make a choice before I literally ate myself to death. I workout, and eat healthy now and it’s the best feeling in the world. I’ve lost a total of 65lbs in a 10 year span but 25lbs since Jan 2011. People tell me I look a lot younger than my age by at least 10 years. I’m running up to 28 miles a week now. I’m 48 years old and if I can do it, anyone can. Soja for life.

    P.S. I’m about to come off my medication soon. High blood pressure and diabetes free.

  • Suzanne

    Michelle Obama appears to be a member of the U.S. population that has a healthy, non-impaired metabolism and can enjoy a simple starch like potatoes regularly without insulin resistance and accompanying weight gain over time. She is in the minority.

  • Emma

    Thanks for the intelligent points on this issue! As we must always be reminded, correlation does not equal causation, and I found the initial reports on these studies to be quite misleading.

    I’m also not at all convinced that starchy foods have anything to do with weight gain. I lived in Japan for a number of years, and was in the very Japanese habit of eating multiple bowls of rice at a sitting. I didn’t gain any weight until I discovered a way to mail-order cheese– and the pounds came off when I topped indulging, since one could only order very large quantiteis at the time. Also, the Japanese have a much smaller problem with weight than we do here in the U.S., all while eating huge amounts of plain white rice. I don’t buy that genetics argument, either, because we are seeing significant increases of overweight even in Japan, as people abandon a traditional fish-rice-vegetable diet in favor of McDonald’s. Again, correlation is not causation, but there’a s certain common-sense logic here that tells me, at any rate, that highly processed foods are linked to unhealthy weight.

  • Marc

    Something that you did not mention but may help explain why french fries are among the highest: french fries are commonly eaten along with sugary beverages and fried/red-meat/highly-processed sandwiches. These complementary items are also associated with positive weight gain, and this needs to be addressed.

    The linked study does not appear to give any information on the co-incidence of eating such products together, or indicate that there is any data controlling for the weight gain due to diets high in just one of these products.

  • I don’t believe that potatoes alone cause obesity. During winter and fall months, we roast potatoes with olive oil, garlic and rosemary a few times a week, my kids eat potato chips occasionally, and enjoy french fries with a burger – and have no weight problem at all.

    If you reflect on the type of places where you normally enjoy french fries, they’re not the kind of restaurant where you’re likely to be eating them with something healthy. It’s usually with a burger, chicken strips or some other guilty pleasure. Eat too much of any of these foods and you will gain weight. Serve that burger with a white bun, soda and finish it with dessert and you have a recipe for obesity.

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  • Marc

    To clarify my previous comment, I emailed the author of the study about the coincidence of consumption of the products and whether they are additive or correlative in their analysis. He replied:

    “As we describe in the paper, the changes in intakes of these foods and beverages were not correlated. Findings are also multivariable-adjusted for all changes simultaneously.”

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  • Jon

    Surprised to see butter on the list. Most of the people I know who are obese can’t afford real butter or are vegans. Perhaps it’s a sign of “I didn’t know I was eating fake…”, as most of them even refer to margarine as “butter”. Also, I can’t possibly see soda having such little effect; most people I know who drink sodas can go through several bottles a day.

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  • I think that eating french fries regularly can add some pound to your body.But don’t agree with the fact that people who eat potatoes have a sedentary lifestyle as Thibault said.Its just a matter of choice.