Is the Potato Making You Fat?

Small potato on a scale You eat the same foods, do the same things day in and day out, but sud­den­ly your clothes start to fit a lit­tle tighter.  There is no deny­ing it, you’ve gained weight.  You are not alone!  As we age, we gain on aver­age about one pound of weight a year.  This may not sound like much on its own, but once you add 10–20 years, it can bump you into the overweight/obese cat­e­go­ry.

The rea­sons for this expand­ing waist­line are as numer­ous and com­plex as peo­ple are. How­ev­er, one recent study from Har­vard has found that cer­tain foods, such as the pota­to, may be part­ly to blame.

The study looked at data from over 120,000 non-obese men and women span­ning 20 years. The Har­vard researchers found that cer­tain foods caused peo­ple to gain more weight than oth­er foods. That is to say, not all foods are cre­at­ed equal. They also found that cer­tain behav­iors led to long-term weight gain.

Here is what they found:

Foods that caused steady weight gain over time.

  1. Pota­toes.  The #1 cul­prit.  Although french fries and pota­to chips were extra fat­ten­ing, even mashed, boiled or baked pota­toes result­ed in weight gain. The rea­son is not clear, but oth­er stud­ies have found that starch­es and refined car­bo­hy­drates result in blood sug­ar and insulin surges, mak­ing peo­ple feel less sat­is­fied, even­tu­al­ly result­ing in overeat­ing.
  2. Sug­ar-sweet­ened bev­er­ages. Not the first time you’ve been told to stay away from soft drinks.  Oth­er stud­ies have con­sis­tent­ly found that soft drinks add extra calo­ries and cause weight gain. If you still drink sodas, now is the time to rethink your drink.
  3. Unprocessed and processed red meat. Eat red meat in mod­er­a­tion.  Oth­er rea­sons to eat less: red meats are high in sat­u­rat­ed fats which raise cho­les­terol lev­els, includ­ing LDLs, the “bad” cho­les­terol.  Processed meats have been found to cause heart dis­ease and dia­betes. 
  4. Sweets, desserts and refined grains. These foods are usu­al­ly eat­en in addi­tion-to a meal and not instead-of,  adding extra calo­ries and caus­ing weight gain.  

Behav­iors that result­ed in weight gain:

  1. Alco­hol
  2. Smok­ing
  3. Sleep. Less than 6 hours or more than 8 hrs.
  4. TV

Foods that result­ed in less or no weight gain:

  1. Fruits and veg­eta­bles. Anoth­er rea­son to pile on the greens.  Oth­er health ben­e­fits include: reduce blood pres­sure, reduce your risk of heart dis­ease, stroke and some can­cers just to name a few.
  2. Whole Grains. Besides the weight loss ben­e­fit, whole grains are full of nutri­ents and fiber.  Whole grains low­er cho­les­terol, low­er insulin lev­els, pre­vent cer­tain can­cers, keep you reg­u­lar and help you feel full. 
  3. Nuts. Nuts may be high in fat but these fats are the good- mono and polyun­sat­u­rat­ed fats.   Eat­ing a hand­ful of nuts is bet­ter for you than eat­ing a hand­ful of chips. Caveat ‚watch the por­tion sizes.
  4. Yogurt. This was a sur­pris­ing find­ing.  Researchers believe it could be the active cul­tures or pro­bi­otics found in yogurt which may change your diges­tive tract. What­ev­er the rea­son if you want to add yogurt to your diet keep it non-,or low-fat.

Behav­iors that result­ed in weight loss:

  1. Exer­cise.  Find an exer­cise you always want­ed to try or do some­thing you already like, you will be more like­ly to stay with it long-term.


Click below to hear Dar­ius Mozaf­far­i­an, one of the Har­vard researchers, dis­cuss the find­ings first hand.


Some final com­ments.   Cohort stud­ies like the ones that were ana­lyzed in this study have a few flaws. One major flaw is that such stud­ies can only demon­strate  “cor­re­la­tions”, or “rela­tion­ships” between cer­tain fac­tors, with­out nec­es­sar­i­ly demon­strat­ing “cau­sa­tion”. For exam­ple, peo­ple who ate yogurt didn’t gain as much weight as those peo­ple who didn’t eat yogurt. This does not nec­es­sar­i­ly mean that when you eat yogurt you lose weight but it could sim­ply mean that yogurt eaters are more health con­scious in gen­er­al and that’s why they eat yogurt to begin with.

Despite this flaw, these find­ings are sig­nif­i­cant and in gen­er­al excel­lent advice.  The next time you order a baked pota­to instead of fries you might want to order a sal­ad instead.




D. Mozaf­far­i­an, T. Hao, E.B. Rimm, W.C. Wil­lett, and F.B. Hu.  Changes in Diet and Lifestyle and Long-Term Weight Gain in Women and Men.  The New Eng­land Jour­nal of Med­i­cine.  2011; 364:2392–2404.

Malik VS, Schulze MB, Hu FB. Intake of sug­ar-sweet­ened bev­er­ages and weight gain: a sys­tem­at­ic review. Amer­i­can Jour­nal of Clin­i­cal Nutri­tion. 2006; 84:274–288.

Liese AD, Roach AK, Sparks KC, Mar­quart L, D’Agostino RB, Jr., May­er-Davis EJ. Whole-grain intake and insulin sen­si­tiv­i­ty: the Insulin Resis­tance Ath­er­o­scle­ro­sis Study. Amer­i­can Jour­nal of Clin­i­cal Nutri­tion. 2003; 78:965–71.

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