Seth Roberts, Guest Blogger (Part II)

Here’s another post from Seth Roberts, our guest blogger. 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 Seth), here (research extras and pix), here (the first round of reader comments), and here (for Seth’s first guest-blog, including comments and questions).

Dietary Non-Advice
Tues., Sept. 13

I reflexively checked this blog several times yesterday (Monday). And each time I realized: If there’s going to be new content . . .

Because I hope to write a diet book I am not going to be giving advice, at least until my future publisher approves. But I am happy to talk about how I lost weight and how I maintained (and maintain) the loss. With that in mind,

1. The Times article wasn’t terribly precise about what I do now. For good reason: Neither am I. I used to drink carefully measured amounts of fructose water or extra-light olive oil — amounts containing about 100-300 calories per day. Now I measure nothing. I am sure however that my total caloric intake from what I will call unusual foods has not changed. The unusual foods currently consist of canola oil, sucrose water (much more convenient than fructose water), and most days a raw egg, swallowed quickly, as the Italians do. Ah, food taboos. I repeat: I am not recommending this (or anything else). I got the idea from a friend of mine; a raw egg swallowed quickly is a relatively diverse source of calories without taste. Perhaps she got the idea from the Italian custom. I have only been swallowing raw eggs for a few months and overall am beginning to think they are more trouble than they are worth. The child in me wishes there were more opportunities to bring it up in conversation. Just as when I was a graduate student I enjoyed saying (truthfully) that I subscribed to the National Enquirer. “That’s worse than Playboy!” someone said.

2. I am leaning toward consuming the sugar water hot in the evenings. Somehow it tastes better then. An Italian friend of mine says that when he was young, that’s what his mother gave him — hot sugar water before bed time. If the critics of sugar wish to malign an entire country of devoted mothers tending to their children . . .

3. Before he studied food intake, my friend the physiologist Michel Cabanac, at Laval University, Quebec, studied temperature regulation; and his work in that area may have helped him understand food intake. There is a body-temperature set point: a temperature the body tries to maintain by increasing or decreasing not only how much we sweat but also how pleasant we find heat and cold. Michel found that there was a circadian rhythm in the set point: it went up and down with a 24-hour rhythm. The circadian rhythm of the set point causes the more obvious circadian rhythm in body temperature. How pleasant we find heat varies with the time of day; a warm shower will be more pleasant in the morning (when our set point is rising) than at other times (when it is no longer rising). This doesn’t predict, I admit, that hot sugar water should taste better in the evening. Michel also found (or perhaps someone else found this) that the body temperature set point depended on the external (air) temperature: When it was cold, the set point went up. Because he knew this, it was easy for him to believe that the body fat set point also depended on external conditions. That is the general idea behind my weight-control theory.

4. I don’t know if canola oil works. I haven’t been doing it very long. For a few years, I used extra-light olive oil to maintain my weight loss. I’m sure it works — for me. I swallow it easily. Lots of people don’t. If anyone understands what causes the difference — why it is easy for some, hard for others — please let us know. Perhaps someone has had an experience that changed easy to hard or hard to easy.

That’s enough non-advice for now. I will return to the topic in future blogs — check back often!


I remember a diet book from the late 80's called "The Paleolithic Prescription", the premise of which was that our bodies haven't evolved beyond those of the Neanderthal, but our diet and lifestyle have changed markedly. Live like a hunter/gatherer and you'll have a happy body.
Drinking sugar water is certainly easier than the paleoprescriction of walking everywhere, bending over to pick stuff off the ground, fasting for a week on occaision.
I went to and found a veritable bloom in "Stone Age" diet books, Neanderthin, etc. Looking forward to Seth Robert's book.


I am curious to know if Dr. Roberts knows his triglyceride and LDL cholesterol count? A post at suggests that this type of diet is like the one that killed runner Jim Fixx who dropped dead of an unexplained heart attack.

It sure is tough trying to make an informed decision about diet and weight control these days!


Of course, we haven't evolved much since the Neanderthal, since the consensus is that the Neanderthal was actually a separate species from Homo sapiens. The point does remain valid though, 3612.

Craig Perko

I'm certainly no expert, but I would suggest that sharing advice and writing a book are far from conflicting actions.

The important audience right now is the early adopters. If you charm them with advice and personality, then you'll have a faster, higher adoption curve when you publish. Plus, most of the people who benefit from your direct advice will go on to buy the book anyway.

Of course, my advice should be taken with a grain of salt. Unlike yours, which should be taken with a tablespoon of sugar. :)


Fixx's diet was so completely different from Roberts' that the suggestion they are in any way similar is extraordinarily disingenuous. (Fixx advocated a fairly radical very-low-fat, low-protein, low-calorie diet. He was a strict vegetarian, didn't take dietary supplements. In other words, his diet is virtually nothing like Roberts' except for the word "fructose".) Besides, it is extremely hard to say that it was his diet that killed him. How do you separate that out from genetics (he came from a family with heart disease, his father died of a heart attack at age 43)? From the fact that he was a smoker much of his life? Or that he spent much of his life overweight? There is a reason real science is based on decent sized cohorts rather than anecdotes. (Which is, of course, the same exact problem Roberts' theory/diet currently suffers from.)


Sunday's article and the new blog entries have changed nothing for me. My vote still goes to the Diet of Worms.

Jonathan Schwartz

I really don't see what this has to do with Economics. The link to econometric methodology in the NYT article (using lawsuits as an instrument) seems like a stretch. Not that everything has to be all economics all the time. I guess the idea is that Seth Roberts is to nutritionists as Levitt is to economists. I would be very interested in Levitt's opinion of whether Roberts' result is reasonably good evidence of the effectiveness of the diet. I seem to remember a previous post about the dangers of n=1.


If you haven't already seen it, you should visit this site:

which takes issue with your use of fructose and implores you to consult with several university colleagues.

BTW, the concept of the metabolic thermostat and set point was employed by a diet guru at least 20 years ago. The program was published by a company called Cybermedia run by John DeVore.


If you haven't already read them, you should visit the posts from the first blog which dealt with this issue.


I tried a tablespoon of extra virgin olive oil yesterday and of canola oil today. They both were unpleasantly greasy but basically tasteless. However the olive oil left an unpleasant, burning aftertaste/sensation.

Neither one did anything for my hunger, I ate just as much as usual at my subsequent meals. I'll try it for a few days and see if I get any results.


On the subject of making oil more palatable -- I've only been doing this for 2 days, but I found refrigerating the oil makes it a little less icky. Either way, it's gone down much easier than I originally imagined. I use an oil called Enola, which is a combination of canola and soy oil. So far, it's working amazingly well. I have very little appetite.

Ken Rawlings

I agree with Craig Perko. I was disappointed by your announcement that you wouldn't be giving advice to people due to future publisher considerations. I can't speak for others, but that stance makes me less likely to purchase your book instead of more likely. Think about it -- as Craig said, you have an audience of eager early adopters here. Treat them well and you have a source of word-of-mouth advertising, not to mention that the dialogue represents an opportunity to find out what sorts of questions and issues people have about your diet, which can then be addressed in your forthcoming book.


Also, I've found I get a weird little headache shortly after ingesting the oil. Very mild and it doesn't last long. At first I thought it might be hunger, but I don't think so now. Perhaps a message from my lizard brain?


Hello there.
I read with great interest your various downloadable papers, and I think my questions would fall under "dietary non-advice". Please forgive me if I overlooked this information in your papers.
1. During the weight-plummeting, 90ml of fructose/day stage of the experiment, approximately how many additional calories were you taking in? Rather, was the primary effect a metabolic change, or the appetite reduction?
2. You noted that to keep your desired weight, you were taking in approximately 1200cal. a day. That's pretty low for a maintainance caloric intake, isn't it? The USDA calculators state that for a 5'11", 160#, moderately active, 52y.o. man, 2690cal. are needed to maintain weight. So does that suggest that the fructose has _reduced_ your metabolism?
3. You mentioned drinking tea to satisfy 'a [new] desire for taste' (p31, UofC Postprints). You didn't have a desire for taste before? And did you avoid the tea as well during the fructose water times, or was that taste-association ok?
I wish I was a scientist..



Doesn't everyone that hocks a diet pill on a TV infomercial have some scientific justification for why it works and have examples of people that lost weight?


According to one of his published papers, the sugar water helped Dr. Roberts cut his calorie intake from 2600/day to 1200/day.

To me, it appears that fewer calories is the cause of the weight loss, not some magical property of sugar water that allows you overeat and not gain weight.

Since the sugar water suppressed Dr. Roberts' hunger, he ate less food in an ad-lib state... and lost weight.

To me, this story is more about a novel approach to suppressing hunger rather than "tricking the set point" (at least as I understand his definition of set point).


same anonymous as 4:47pm above.
addendum with apology re: my no.2 question - I hadn't read carefully/remembered properly your comments about metabolism shift after weight loss in your UC paper.
Let's just forget I asked that question.


The NY Times article said Dr. Roberts is "a serious foodie." And that he eats pretty much whatever and whenever he wants. If he's taking in 1200 kcal per day, and 100-300 kcal of that is either oil or sugar water, plus a raw egg at roughly 75 kcal, that doesn't leave many calories for "serious food." Does it?


Why swallow the raw egg quickly: what a perfectly good waste of a raw egg?

As a kid, I remember doing this: take raw egg, separate yolk from white. Slurp down the white -- no worse than a mouthful of snot. With the yolk, mix in a few drops of soy sauce and a tablespoon of sesame seed oil. Drink and enjoy.

I have no idea what kind of caloric ass-kicking you get from this (raw egg, sesame seed oil) but it sure is tasty. Mmm.


I read your paper on Pavlovian Theory of Weight control. I loved it! I don't need to lose weight but I must say this sugar water stuff works like magic for me. The paper got me thinking, we know if you quit smoking there is weight gain. Do you believe this is due to smokings known effect on your ability to taste. If your taste goes so does your CS signal.