Seth Roberts on Acne: Guest Blog, Pt. IV

Here is the latest post from our guest blogger, Seth Roberts. If you need to get up to speed on Seth’s unorthodox research with weight-loss, mood, and sleep, click here (our N.Y. Times article about him), here (research extras and pix), here (the first round of reader comments), and here, here, and here for his earlier blog postings.

Thu., Sept. 15

I told Dubner my students laugh when I say “pimple.”

“They laugh when Levitt says ‘crack cocaine,'” Dubner replied.

My acne began as a teenager. These things go away with time, a dermatologist told me. When, I asked. Everyone is different, she said. I wondered: Doesn’t she know the concept of average? Whatever she prescribed, it didn’t work very well. When I was a graduate student, I saw a different dermatologist. He prescribed both pills (tetracycline, a wide-spectrum antibiotic) and a cream containing benzoyl peroxide. I used them. They too didn’t seem to work very well.

Around that time, I began to do little self-experiments simply to learn how to do experiments. I was following the advice of Paul Halmos, a mathematics professor: The best way to learn is to do, he had written — words that slowly changed my life. The first way they changed my life was when my little experiments expanded to include my acne. It is hard to measure acne, I thought, so I am probably wasting my time. But it was worth a try. I did my best to count the number of new pimples each day. I varied the number of pills I took: Week 1 a certain number per day, Week 2 a different number, Week 3 the first number. The results implied that the pills had no effect. I told my dermatologist this result. “Why did you do that?” he asked, truly puzzled and slightly irritated.

I did more little experiments varying the number of pills per day. The results kept indicating the pills were useless. One day I ran low on pills, so I started to be more careful about using the cream, which I considered useless. My acne suddenly improved two or three days later. It was cause and effect (speaking of delayed causality). You could just look at the time series — one number per day, the count of new pimples — and see this. Just once, if I remember correctly, I stopped using the cream. Two or three days later, my acne got worse. I resumed the cream. Two or three days later, my acne got better. :-)!

That was even better than learning that something was useless. Consistent use of the cream helped a lot. Over the next several years, I only made two further advances. First, I found that a Vitamin B pill helped, probably a multi-B pill. Second, based on the idea of a two- or three-day latency, I discovered that certain foods caused pimples. If my acne suddenly got worse, I tried to remember what I had eaten two or three days earlier. Diet Pepsi and pizza were the main culprits. Taking all this together, I reduced my acne about 90%. Then, as predicted, it faded away.

A few months ago I saw a dermatologist about a different problem. I couldn’t resist: What causes acne? I asked. Well, not diet, he said. I knew this was false. And, really, how could you say such a thing without testing hundreds of different diets — at least? Which no one had. Several years ago I asked my friend Katharine Milton, a Berkeley anthropologist, whether the indigenous people she studies have acne. No, she said, unless they eat foreign food. The anthropologist was right, the doctor was wrong. The situation reminded me of something in an NIH-sponsored online medical encyclopedia: dental malocculsion, it said, “is most often hereditary.” Whereas the work of Robert Corruccini, a professor of anthropology at Southern Illinois University, such as this, had convinced me that dental malocculsion is due to soft food.

It does seem to boil down to laughter, or rather fear of laughter — fear of loss of status. Dermatologists have a fancy word for pimple but they don’t have a fancy word for small. To slowly vary the diet of one patient at a time, year after year, to figure out what dietary elements cause acne is not even close to being sufficiently high-status. It is too risky, not to mention too grubby and too low-tech. It isn’t the sort of thing that produces several publications a year, or a large grant. So a whole class of promising solutions — dietary changes — goes unexplored.


For the last few days I've been trying to think about the relation between 'set-point' and 'metabolism'. It would be interesting to see what happened with someone at a healthy weight, who began taking sugar-water or oil between mealtimes, but continued, despite a reduced appetite, with the same caloric intake as always (including the sugar/oil in the count), and if had a weight change or not. (I am sorry if that too-long sentence got grammatically fershuganah.)

I think all of the diet questions are fueled in part by a fear that in trying it out, and getting it wrong would somehow wreak havoc, and say, make it then thereafter not possible to achieve a lack of appetite from swallowing 2Tb of flavorless oil, if one had once had the oil 20minutes after, say, a snack, and had permanently made a calorie-flavor link, never to be broken. It would be interesting to hear from Seth (hint hint!) about such malfeasances, and assurance or warning about such.

*Note to Sally, Enova-taker: I'd try a nice organic cold-pressed oil instead and see if that little headache doesn't go away -- my semi-educated guess would be that it very well may be related to the laboratory-made, chemically expelled nature of the Enova.



One of the problems with acne is the many different factors involved. Oil gland overproduction, skin irritation, skin cells that are irregular so that they do not slough correctly, and bacteria on the skin are all credible factors that can mix in a myriad of ways.

The creams you are speaking of generally either disinfect the skin, which prevents infection leading to white heads, or they involve vitamin A derivatives which can both exfoliate skin and encourage regularity of skin cells.

The sun can help in the short term with acne because it dries out your skin, but this can be disasterous for some in the long term because it can both damage the skin and lead to more intense oil production at a later time.

Sensitivities to both food and harsh acne medications may actually cause acne in some. In women determining these specifically can be further complicated by hormones, which can also be factor in acne.

I know all of these things because both I and my sister continuously fought serious acne from the time we were 17 until well into our twenties. For me the only thing that got rid of my acne, and I have tried everything else because I was scared of the side effects of this, was the drug Accutane and I am not the only one this is true for. After that first treatment I found that part of my problem had to do with my skin's ablity to slough skin cells, necause I will still get pimples once in a while if I do not exfoliate regularly.

Anyone who has struggled for any length of time with acne and has a dermatologists that has not covered every single one of these options and more in detail needs to change their dermatologist.



what an unexpected pleasure to read something that hits so close to home, and true. I'm over 40 and have suffered from various forms of acne all my life. over the past few years I've adopted some healthier habits (quit smoking, quit drinking etc.), and while my overall appearance improved, the acne would still crop up at the most inopportune, and unexpected, times. and I've engaged in the same sort of self-examination that Seth describes most of my life. I suppose that since it was such a basic, daily, (and nutritious) part of my daily diet, I never thought to remove orange juice from my diet. bingo. like magic, the zits started disappearing. not 100%, of course--stress is a big factor and other foods too, but the acid level in OJ seems to have been the worst single element as far as the diet/acne relationship went. goes to show that in order to be truly objective, you really need to evaluate EVERYTHING. thanks for the great read....



i'm a little disappointed in this post. Topical antibiotics work for a limited period of time, and as another poster has pointed out, acne is caused and exacerbated by multiple factors, and treatment should target as many as possible. Your solution - diet and topical disinfection is only going to work for a minority, with relatively mild acne. Moreover, the food triggers are going to be different for different people.

I can tell you that pizza and diet soda and orange juice have no effect on my acne because I eat none of these foods!

OTOH, retina is a wonderdrug for me, and oral antibiotics worked, while topical antibiotics never did seem to do much alone or in combination with these. Still, adding some disinfection to a daily routine is useful in targeting any remaining bacteria.

It doesn't seem to me that you've done a lot of research on the causes of acne and available treatements. There is never going to be a single diet that anyone will be able to prescribe for acne - at most, there will be a list of foods that a dermatologist can ask patients to look out for and see if they trigger acne. But all that is relatively messy and unnecessary, since acne is nowadays much more treatable than in the past. Avoiding trigger foods is truly a stone age solution.

Very disappointing analysis.



Read NYT article. Went to Blog on midday Monday. Started the sugar and water and also have switched to the oil when I did not want sweet taste. I am Gym Nut(spinning)and keep detailed weight and workout stats. I weighted myself Monday evening after spin and I was 235.6. This evening same time. I was 231.0. So far I am a believer

Bill Quick

"-Limiting caloric intake can make people weigh less, especially if you are fat, but that isn't necessarily going to help you to live longer."

This is dead wrong. Every calorie restriction study I am aware of shows the subjects live longer. The greater the restriction, the longer the lifespan (up to certain limits).


Wow. I did not realize so many people experimented on themselves to treat acne.

This summer, I set out to get rid of acne--and the scars. I broke out quite a bit after about 6 months at an urban college where access to healthy food, which I tend to stick to having a cardiologist father, was limited. I did not get proper nutrition because my calorie intake was lower than I realized (I suppose I fell into the trap of picking at the nasty prepped food from school when I got it).

Having done some research, gone to see dermatologists, and tried the reasonable suggestions, I have found that eating meals with lower glycemic loads when I can, taking fish oil supplements (good ones), staying hydrated, cooking with olive oil, and limiting my cappuccino intake to one in the morning helps a whole lot. The only suggestion from my dermatologist that I found helpful was to try Alpha Glycolic facial cleanser.

Thus avoiding trigger foods has certainly been key to my treatment.



I had terrible acne including cystic acne when I was in my early twenties and thirties. I did the usual route of antibiotics, creams, etc. Those didn't work. I did a course of accutane which did work but then the acne came back a few years later.

I began to believe that my acne was hormonal and no short-term course of antibiotics was going to make a difference. So I went looking for a more long-term solution. What finally worked was birth control pills and Retin A. I still got the occasional break out but nothing as bad as before.

I've always known about the common triggers of acne: chocolate, caramel colored soda, shellfish, etc. The only one that had any effect on me was the soda. I never thought to experiment more. But I'll definitely file this away for when my daughter gets older.

I do regret using the Retin A because I believe it damaged my skin as well. My face sweats a lot more than it used to.

Now my daughter has a mild case of ecezma. It's pretty much constant but mild and doesn't seem to bother her. Elidel has little to no effect. After my Retin A experience, I'm reluctant to try any other prescription cremes. She's young enough, it may go away on it's own, but I think I'll do a bit of experimenting to see if there isn't a food sensitivity behind it. Any advice? My thought is to journal everything she eats and comes into contact with and the condition of the rashes.

Chris (of the 9:23 post), would you mind sharing your list of rosacea triggers with the rest of us? I wonder if these skin conditions don't share some of the same triggers.

Off topic, the diet information sounds tempting. A fast, easy way to drop the extra 20 pounds I'm carrying. But I'm not wild about having to drink sugar water or oil for the rest of my life. So I'll try the old-fashioned way first and keep this in my back pocket.

And one final comment: Seth, I'm grateful you are curious enough to have made these experiments, meticulous enough to have such good data, and generous enough to share your findings. There are so many people I plan to share this with. Not so much to say "try this." But definitely to say, "Think about this."



The Arbit Council

wow, didn't expect to find such a good discussion on acne at freakonomics of all places!

i'm 25, and have been plagued with acne for the last 10 years - constantly. On my face, back, shoulders, even my earlobes! I used to have eczema on my right foot till I was 15 - it spread in small patches to the other foot too - a strong homoeopathic dose of Rhustox (+soemthing else) drove the eczema out mostly (since then there's only a very small patch on the other foot, that no longer oozes.) but unfortunately, gave me rashes all over my back and my legs that first bled, and then turned into scars that are still to fade. (sorry for being so graphic :-( )

well this is mostly abt my acne, so i'll refocus. I've used various pills (allo/homoeopathic and ayurvedic) and various creams. One thing I've never regulated is diet. As I've never put on weight, I've had no reason to not be very liberal with my food. And btw, since childhood, I've added sugar to almost every meal - like, a spoonful!

Reading about Seth's expts. and other people's comments, I guess I will now maintain a diary to track my diet. Actually, I had a similar idea sometime back, but I thot it would be silly! Well, my initial idea is now to maintain the following:

Time of meal
Glasses of water consumed in the day
Stuff eaten
Pimple status (count and complexity? like..small bump..or..pus filled dinosaur!)
Whether or not I shampooed my hair today!
Whether or not I exercised..

(Heck I've a digicam now.. so maybe I can photograph myself! :D)

Two things I think have affected me include whether I have had a haircut - that probably reduces the danddruff that falls on my face! - and whether I've shaved - shaving followed by aftershave makes me feel better usually.

Any advice is welcome on thearbitcouncil ATTHERATEOF gmail DOTTY com


The Arbit Council

Adddendum to my comment above:

My skin also scars easily - little cuts anywhere (except palms and soles) leave a mark that becomes permanent.

(sorry I think I've statred using this as a personal rant page :D)


Seth, interesting acne post and intriguing discussion, too. That was perceptive of you to discover a diet-acne connection.

Indeed, as you, Paul Bowers, Masa, and others have said, connections between acne and diet have been found and documented through extensive research.

In particular, I'd suggest you check out the work of Dr. Loren Cordain. He's done some groundbreaking research in this area.

He conducted extensive studies in various parts of the world to document how diet impacts acne.

Sure enough, he found that the natives, who are eating veggies, fruits, lean meats, and less or no processed foods have no acne. His studies are quite remarkable.

In fact, Dr. Cordain has a recent paper on the subject:

Cordain, L. Implications for the role of diet in acne. Semin Cutan Med Surg 2005;24:84-91.

Here's a link to a PDF of the article:

1. Cordain, L. Implications for the role of diet in acne. Semin Cutan Med Surg 2005;24:84-91.

ABSTRACT (taken verbatim from his website):

"Within the dermatology community, a general consensus has emerged that diet is unrelated to the etiology of acne. Except for 2 poorly designed studies, now more than 30 years old, there are few objective data to support this notion. In contrast, a large body of evidence now exists showing how diet may directly or indirectly influence the following 5 proximate causes of acne: (1) increased proliferation of basal keratinocytes within the pilosebaceous duct, (2) incomplete separation of ductal corneocytes from one another via impairment of apoptosis and subsequent obstruction of the pilosebaceous duct, (3) androgen-mediated increases in sebum production, (4) colonization of the comedo by Propionibacterium acnes, and (5) inflammation both within and adjacent to the comedo. This article will provide a review of the currently available literature on the association between diet and acne vulgaris as well as a discussion of the physiologic principles that may underlie this association."

Gee, I've been offline (on vacation now and things are really popping over here)! Will have to take more Freakonomics-Seth Roberts breaks!)

Oh, for those of you so inclined, Dr. Cordain also has written a book for the lay person (in addition to his plethora of medical studies). The book is The Paleo Diet.

(FYI, I am not in any way affiliated with Dr. Cordain, nor do I stand to gain in any way if you purchase his book. I simply discovered his work while working on my book, SUGAR SHOCK!)

Author, SUGAR SHOCK! (Upcoming)


Paul Bowers

a diet that keeps people alive for the longest time? based on your "balanced diet" answer and assuming you want to live a long time, i guess a healthy diet, according to you, is 20% fat 20% protein and 60% carb. just out of curiousity, how did you come to this conclusion? you haven't lived a long time yet (based on your avatar). also, we have essential fats and essential amino acids; know of any essential carbohydrates?


. . . there's a book called The Sugar Blues that talks about how sugar correlates with acne . . . The book was written in the 70's and is written in hipster language through most of it, but the info is very interesting. That is the only thing that makes me pause in regards to your diet: how simple sugar, and specifically refined sugar, effects mood, and toxicity level in the body (one sign being acne as the skin does its part to detoxify). I tried the sugar water for three days and lost three pounds and lost that sensation of serious hunger that I usually have. But the sugar left me more than a little jittery and I know that in the past, prolonged use of sugar for me eventually brings on big mood swings. I'm working with the loive oil instead now, but it sure doesn't taste good . . . the nausea is a little much and not sure how long I can keep it up . . . interesting stuff though . . .


I see patients with skin disorders on a regular basis. The "party line" on acne is that diet has no effect. This conclusion is based on short term studies with variations of the typical western diet. I have long suspected that a high calorie western diet played a long term role in hormonal status. Why else are we seeing more women with polycystic ovarian syndrome, acne, hair loss and hirsutism? I see 20 year olds with hair loss and 50 year olds with acne. This is "normal" only in our food environment. (BTW what is a "normal" testosterone level? The laboratory normals are based on averages in our country, not ideals.)

Although I don't know if the changes Mr. Roberts made would be effective for everyone, it is great to know that, for some people, small dietary changes can give symptom relief.

Ugly Naked Guy

I excitedly told my wife about Mr. Roberts findings and methods. She listened intently and then said, "There is no way this guy could be married."


A warning to everyone being treated by antibiotics for acne...they can cause depersonalization and doctors don't assess for it! My daughter suffered with this for 1 1/2 years before just by luck we found out about this risk. And her acne has not improved!


from an evolutionary biology perspective, acne as caused by stress/bad food would make an interesting hypothesis . . .
i.e. acne looks bad in the wild (hey, isn't the scientific name for the most common form acne vulgaris?), don't get to spread genes . . .

btw, I too have acne, at 19, and will try to track foods and their effects


resumably on the basis of controlled studies, many dermatologists are insistent that diet does not cause acne. Other studies and a wealth of many persons' own experience suggest otherwise. One possible way to reconcile this clash: it may not be *ingesting* certain foods that triggers acne, but *handling* them, by getting the oils (and other compounds) on the surface of the skin (where they are either tranferred to affected areas or simply cause a skin-wide reaction in area untouched).

Possible tests for self-experimenters: (1) Eat your pizza, chocolate, and other "trigger foods" carefully with utensils, and clean up immediately afterward -- and see if that avoids the breakout. (2) Handle your pizza, chocolate, and other trigger foods -- even rubbing on affected skin areas -- without ever ingesting it, and see if the same delayed breakout occurs.

Current knowledge, derived from controlled, often double-blind studies is that acne is not related to food. From my own experimentation I can only say: this is true. Eating other things doesn't help. However, just like in your case, it's hard to draw conclusions from your own observations. Sample size is 1. Placebo effect (a proven effect, by the way!). Subjective judgements: you evaluate your own status.

How about this: Pepsi makes you feel slightly unwell. Therefore, you are biased towards what you see in your face. Result: your observed skin status and your Pepsi intake correlate. However, you're concluding that there is a direct causal link between the two, which is wrong.

From a medical perspective, I would think that your other observations make sense. Bacteria [colonies] develop resistencies against antibiotics over time, which means that youre tetracycline may not work as well (this is my personal observation as well, btw.). BPO is a well-known and much-prescribed topical treatment. It's not surprising that it works.

There's a fun article in a recent (2004) issue of "Behavioral and Brain Sciences" about self-experimentation. Worth checking out.

Lastly, check out Accutane. The only stuff that really helps in the long-run.

Disclaimer: I'm a non-medial scientist. I have suffered from acne for 10 years now.



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