For folks who have engaged in scientific research, read scientific journals, or done any work with statistics, “n=1” makes sense.  If you don’t fall in any of those categories, you may be wondering, “What’s this n=1 business, anyway, and what does it have to do with the food that I eat?”

The letter “n” refers to the concept of “sample size,” so when you see “n=1” that means the “study” involved only one person.

In Paleo and Primal parlance, “n=1” is used very frequently.  I’ve used it on occasion, too.

Amy Berger wrote a terrific piece entitled, “N=1=You” for which fully explains the concept as applied to nutrition, so I won’t take up space reiterating what she’s already said.  But I do want to delve a little into how the concept of n=1 gets operationalized.

Let’s take a look at three different people for whom eating “healthfully” is a priority.

Conventional wisdom would hold that if each of those three people ate some version of the USDA MyPlate template, they would be eating healthfully.  But, if you’re an n=1 kind of thinker, you may believe otherwise.  Let’s dig deeper into each of those three people’s lives and we’ll see how n=1 makes a difference.

My Dad

My father survived a bout with a Stage IV head and neck cancer that was diagnosed in 2003.  The intense radiation from his therapy likely caused his subsequent massive stroke, which occurred in 2008.  As a result of his cancer and his stroke, he has an extremely impaired swallow function.

For my dad, “healthy” looks like this:

KP FoodIt’s highly processed.  It’s from a can.  It’s packed with synthetic vitamins and minerals.

It’s also the only stuff he can get down.

Aspirational pneumonia is an ever-present threat for my dad.  We’ve faced it before, and as his swallow function continues to degrade, we will likely face it again.  Accordingly, “healthy” for him is pureed, processed, and enriched.

Whole, fresh, unprocessed foods?  They would kill him.

I will add, he somehow always manages to get down chocolate cake when we offer it to him.  And you know what?  I serve it to him with nothing but joy knowing that it’s one thing that he can still do that makes him really, really happy.  Because food can also speak to the spirit.

My Mom

If my mother were to adhere to the MyPlate standards, she would be sick all of the time, as proven by a near-lifetime of n=1 experimentation.

Highly gluten intolerant, she is also very sensitive to dairy foods.  Eating “whole grains” literally tears her up inside.  I spent years telling her that just couldn’t be the case, because “whole grains are good for you!”  (“The government says so!”)  Then, I decided to start listening to what she was telling me about how the “healthy” food was making her feel.

But let’s add another layer on to this n=1 thing here, because my mom has a history of thyroid dysfunction.  Accordingly, she needs to closely monitor her intake of goitrogenic foods.  Goitrogens suppress thyroid function by interfering with iodine uptake.

What foods are goitrogenic?  How about …

  • cabbage
  • strawberries
  • peaches
  • pears
  • sweet potatoes
  • broccoli
  • brussels sprouts
  • bok choy
  • radishes
  • turnips
  • (and more)

Not a list you would see and immediately think, “Danger, Will Robinson*!” right?

But for people who already have suppressed thyroid function, overdoing it on the goitrogens can have a profound affect on overall health.    As Sara Gottfried, M.D., author of The Hormone Cure, says:

Slow thyroid? A show stopper.

You cannot realize your full potential in the world if your thyroid is working against you.

So, to reach her optimal health, my mom needs to pay attention to her intake of goitrogens, her iodine, and her thyroid levels.


It would seem that I inherited both my mother’s intolerance for gluten and my father’s penchant for chocolate.  I indulge in a dark 72% cacao soy-free chocolate every single day.  It feeds my spirit and satisfies my craving sufficiently.

After my 2009 endoscopy, when my gastroenterologist told me in no uncertain terms that I was free to eat wheat because I don’t have Celiac disease, I ate wheat and other gluten-containing grains freely.  I continued to stay sick, though, and chased down every explanation that conventional medicine had to offer me.  It wasn’t until I ditched the gluten-containing foods that I, for the first time in my adult life, experienced what I would call digestive peace.

But my n=1 experiment didn’t stop there.  Dairy breaks out my skin and can also cause digestive upset.  Bananas, believe it or not, also cause skin irritation.  And I haven’t been able to eat nuts without acne in at least five years.

Then there are the nightshades.  Lordy, Lordy, Lordy, the nightshades.

Sarah Ballantyne, Ph.D., a/k/a The Paleo Mom has done a fantastic job explaining the issues some people have with nightshades, so I won’t go into detail here.  Suffice it to say that when I substituted roasted eggplant (nightshade!) for pasta and smothered it with tomato (nightshade!) sauce, I would go to bed unable to move my hands.  Nightshades make my joints ache and surely cause other inflammatory problems in my body that I can’t see.

One of the most surprising findings that my n=1 study has led me to is that I do far, far better with veggies that are well-cooked than with raw or lightly steamed ones.  This flies in the face of conventional nutritional advice which cautions against overcooking for fear of losing nutrients in the cooking process.

But here’s the thing: if a food disrupts your digestive process and causes GI upset, it can be the most nutrient-rich food in the history of humanity and still not be “healthful” for you.  If you’re not actually digesting the food, those nutrients just don’t matter.

Since I’ve focused my diet on more meat, starchy carbs, and well-cooked veggies, I feel better and have far fewer tummy troubles than when I was eating “lightly steamed” broccoli on a regular basis.

(If this idea of eating well-cooked foods interests you, read up on the GAPS protocol.)

Finally, one of the biggest discoveries I’ve made in my n=1 journey thus far is that I need to purposefully add salt to my diet.  I have always had extremely low blood pressure.  As in, a doctor once told me that if I didn’t look so full of life sitting in the chair in her office she’d have me taken to the ER based on my blood pressure stats.  Since I eat such minimally processed foods, I don’t get a lot of salt unless I make sure to add it.  I can tell when I haven’t had enough, because I feel wonky.  (Which is actually just how I used to feel all the time.  See, n=1 experimentation can prove really useful.)

Evidence-Based Eating

I absolutely love this piece by Robb Wolf on the shortcomings of relying on the “gold standard” in scientific studies, i.e., a randomized controlled trial.  It gets to many of the reasons why nutrition studies are so utterly difficult to conduct in a sufficiently rigorous way as to meet the requirements of the “scientific mainstream.”

As an alternative, Wolf points to “observation” and notes that in some corners of the scientific universe, observation is seen as a perfectly legitimate way to move the needle of knowledge forward.  He gives some solid examples so go read them.

And n=1?  Observation is all it is.  You eliminate, you test, you limit your study size to yourself and you see how certain foods make you feel.  And if they make you feel bad, you stop eating them.  If they cause you problems, you avoid them.

I try not to characterize foods as “healthy” in my conversations anymore.  That doesn’t mean I never do it, but I am just less and less convinced that there is a universal “healthy” diet.  Genetic heritage, early exposures to things like breastmilk and farm animals, as well as the stage you are in life can all impact what constitutes a “healthy” diet for you.

What about you?  What conventionally “healthy” foods have you discovered affect you negatively?



(*Apologies if you are too young to catch this cultural reference.  I had a fierce crush on Billy Mumy as a wee little child.)

Find this and other posts like it at Nourishing Joy’s Thank Goodness It’s Monday, here!

One Response to “What’s This n=1 Business, Anyway?”

  1. on 29 Aug 2013 at 3:51 pmhot Nai Nai

    some day the “nutritonists” are going to recognize that everyones needs are different…..we already know that one shampoo or lotion or anything might work for one person and might not work for another. Don’t know why it is so hard for people to accept that food tolerence varies too. My body does not work like someone elses.

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