September 7, 2009

High Fat Diet Makes Us Lazy and Stupid?

I've been eating a high fat/lowered carb diet for the past 11 years. During this time I have published three nonfiction books, two of which made it to the tops of their Amazon category bestseller list and one of which, Blood Sugar 101, is currently showing up, on and off, in the top 100 Amazon bestseller list for all disease books.

Over the same period, I've written the PHP-based software generator that creates easily updated web sites for computer-phobic craftspeople. That software is also the platform I use for the Blood Sugar 101 site since it makes it extremely easy to update a web page and I update Blood Sugar 101 frequently. Over this period, in my spare time, I've finished two novels, one of which was recently bought by Avon Books, a major publisher, despite the repeated claim in the writers' media that it is almost impossible to break in to fiction publishing in these hard economic times.

Given how well my brain has performed on a high fat/low carb diet, you can imagine my feelings when I read this latest health headline:

Do High-fat Diets Make Us Stupid And Lazy? To which the editorial answer is a loud "yes."

The use of the word "Us" in this headline is very odd indeed, since the research cited was a rat study. Last I looked, I was not covered with fur, nor did I have a tail, or feast on garbage in alleyways. Have rodents taken over the editing of diet research news?

One begins to wonder. There has certainly been an torrent of publicity over the past few months for rodent studies that purport to prove that high fat/low carb diets will make us stupid, flabby, and/or dead. These studies are funded by organizations like the British Heart Foundation, sponsor of the "stupid" study above, that have a huge stake in keeping the public from learning that the dietary advice they've been pushing for decades--the advice to eat low fat diets filled with "healthy whole grains" is not only worthless, but actually harmful.

Since all the human data confirms the uselessness of low fat diets and, furthermore, shows that high fat/low carbohydrate diets provide the best outcomes for people with diabetes, the stakeholders in the low fat theory have been driven to desperate measures. These measures increasingly involve feeding very artificial diets to rodents whose furry little bodies are adapted to diets extremely different from that of the human omnivore.

To understand just how deceptive the rodent research is that is being marshaled to support the low fat "bitter-enders," I'd urge you to read this blog post:

Whole Health Source: Animal Models of Atherosclerosis: LDL

As Dr. Stephan Guyenet points out, the diets researchers give their little furry friends are obscenely distorted, because that is what it takes to produce the effects they desire. The high protein diet in one recent study that purported to be an "Atkins" diet, fed mice a diet so high in protein that the equivalent for a human would include a daily portion of 17.5 pounds of beef steak, 3.8 pounds of beef liver, or 22.5 eggs.

As only the abstract is publicly available, one can only speculate what the high fat diet was that was fed to rats in this latest tudy. In other rodent "high fat" studies where I have been able to see the details of the diets, the fats used have often been trans-fat filled shortening. Many of these "high fat" diets also supply the carbohydrates that fill out the diet in the form of sugar water or pure fructose.

But whatever the rats actually ate in this latest study, it has huge flaws, starting with the idea that we can measure the "cognitive performance" of a rat in a way that has any implications for human cognitive function and moving on to the fact that the measurements were taken after a very brief exposure to a high fat diet--slightly more than a week.

We know that in humans who are put on a low carbohydrate/high fat diet, there is a period, often lasting up to two weeks, in which the intense metabolic changes that occur, including dropping blood sugars, can lead to temporary mental fuzziness. However, as anyone who has eaten a low carb diet for more than two weeks knows, that short term mental fuzziness is far different from permanent cognitive decline, and once the body stabilizes on the new diet, the result is enhanced mental clarity.

For a human to achieve permanent cognitive decline via diet, they have to eat a high carbohydrate/low fat diet for an extended period. That is because it is the high carbohydrate, low fat diet that, over years of exposure, raises blood sugar high enough to damage the vascular system in the brain. A persistent low fat intake also deprives the body of the fats that are vital for the production of the hormones essential to cognition, like estrogen, and for repair of the tissues in the brain for which cholesterol is essential.

This latest rat study also claims that the high fat diet destroys the rats' ability to exercise (hence the headline reference to high fat intake making "us" "lazy".) To understand how silly the claim is that a high fat intake is damaging to human fitness, you need only read the training manual sent home nowadays with college football players. I saw one when my son was on a college football team. The dietary recommendations? Eat high protein/low carbohydrate foods (which implies a higher fat intake) except before games. Trainers who are graded on their trainee's performance have learned that low fat/high carbohydrate diets are the worst regimen on which to build lean body mass and increase fitness.

But pointing out human results to these low fat fanatics is as effective as it was to tell those Japanese troops fighting on into the 1950s in jungle island enclaves that WWII was over. Having given committed their professional lives to this theory, they will die fighting for it, no matter how much evidence accumulates that their theory is fatally wrong.

Fortunately, human cognition is such that you don't have to take the word of anyone about the impact of a high fat/low carbohydrate diet on your own brain. Eat a low carb diet for three weeks and see what happens to your thinking. If you are like most people with diabetes, it will get clearer, your moods will get rosier, and your creative output will rise.

To counter this latest burst of media disinformation, I'd love it if some of my readers who eat high fat/lowered carbohydrate diets would use the comment section that follows this post to list some of their recent intellectual accomplishments.



Gretchen said...

"As only the abstract is publicly available. . . " Actually, the full text is available to the public. You just have to pay $7 to read it.

Anonymous said...

I began low-carbing in January 2003. Since then, I've completed a bachelor's degree in history and a master's degree in library science, in both cases near the top of my class, all while working full-time.

Interestingly, prior to low-carbing, my blood sugar swings caused such fatigue and lethargy that I had a very hard time completing a work day and then going to school at night, so much so that I repeatedly dropped out. And guess what? During that time I adhered pretty strictly to the low-fat dogma.

Coincidence? I think not.

Jenny said...

I'd rather pay that $7 for a nice piece of imported French cheese. Plus, there is no guarantee that they will explain the exact diet they fed their rats. Often researchers will only give you the composition percentages with no indication as to what exactly supplied the fats, carbs and proteins.

country mouse said...

started low carbing in April 2009. only problem is that it seems to create a persistent depression and low energy. the later symptoms are probably caused by my being on an lactose intolerant anti-migraine diet as well which limits my diet to meat, fruit (non citrus), free veg, and some beans. it is a rare day that I hit my calorie limit at or before hitting my carb limit. the low calorie intake (1200-1500) probably explains the depression/energy loss better than the low carb.

Susannah Anderson said...

I've been on a low-carb diet since around 2000. Since then, I've written a book, studied web design and produced several websites, and become a fairly well-known nature blogger.

And normalized my blood sugars in the process.

Jenny said...

Country Mouse,

You might be someone, like me, who does better with a moderate low carb diet--60-100 g a day rather than a very low carb diet.

I need to use a bit of fast acting insulin at some meals to make that work, but it gives me much better energy than the very low carb diet does. I'll eat 2 very low carb meals and one high carb meal a day. Or one very low carb and two 35 g meals.

Jack said...

This rat just finished a pocket computer program which crunched my last three months of BG tests & predicted an HgA1c
of 5.5%.

Actual ReliOn HgA1c test result: 5.4%

CH < 50 g/day, most days - Have cut my insulin by 1/3 & am losing weight...

thanks Jenny,


Anonymous said...

It was a bumpy road in the beginning (1999) (and to this day, it's still a bumpy road sometimes, but through this website and others, I find the information to be supportive and strongly in favor of high-fat-low(er) carbing) for not only physical, but mental health as well. I wrote and published 'Diet King' in 2005, and eating the right way gave me the clarity and stability it takes to put your heart and soul into a book.

country mouse said...

don't know if this got posted. Had a browser crash.

Sorry for not putting this in the original message but my carbohydrate goal/limit is 120 to 150 g per day. Because of the migraine diet limits and lactose intolerance, it's real tricky to get above the 1200 to 1500 calorie per day mark. In addition, the diet is so monotonous as to suppress the appetite. I eat chicken three times a day and the only thing that changes is what four or five vegetables I have with it.

I've worked with a bunch of folks trying to change things but, there is really not much you can do when huge chunks of the food palette are off-limits.

William Houser said...

I have been on a low-carb diet since I was diagnosed with T2 in March. I have gone from 275# and an A1c of 9.5%+ to 235# and an A1c of 5.8%. Last month I finished the diet part of my "diabetes classes". It turns out that my personal eating plan is 270gr. of carbs, 25gr. of fat and 42gr. of protein a day. That is a week's worth of carbs in one day. Carbohydrates raise BG levels so to lower them you cut the fat? Maybe it works on rats.

Jenny said...


Low fat diets work for diabetic rats, because they are are "diabetic" due to a genetic flaw that isn't one that is associated with diabetes in diabetic humans. They don't do well on high fat diets, because of their genetic make up.

But with every new gene that is discovered as significant in human diabetes, it becomes clear that the rodent "models" of both obesity and diabetes are not models for human obesity or diabetes. Different genes broken == different disease condition.

I believe they are still using that OB mouse for obesity studies, though it is leptin deficient and humans except for one or two families are not.

Ian said...

I've been on a low carb diet (as low as my glucose meter tells me to!) for over two years, losing 30kg and getting HbA1c's of <5.5 in the process.

Last week my wife gave me an IQ test (WAIS III) as part of her psych studies and I came out in the top fraction of a percent of the general population.

Gee, just imagine how smart I'd be if I wasn't on this "lazy and stupid" diet!

Anne said...

Actually the article that Stephen Guyenet reviews is available free.

I have not found the full article, but have you seen this story from Sweden "Fat reprograms genes linked to diabetes"

Here is another reference to the same study. "It is well known that poor diet and lack of exercise make insulin resistance more likely, so one hypothesis is that these things change the epigenetic marks on genes such as PGC-1 alpha. To test that idea, the researchers bathed cells in glucose and fats (chosen as surrogates for bad diet and lack of exercise for obvious reasons) and also in inflammation-producing proteins called cytokines. These proteins, they knew, are produced abundantly in the obese. And obesity, the consequence of bad diet and lack of exercise, is another risk factor for type 2 diabetes. Lo and behold, doses of both fats and cytokines caused PGC-1 alpha to be methylated."

I do want to see the complete article. The first reference mentions they used palmitic acid as the fat. Does "bathing cells" give the same result as eating? Although animal and vegetable fats are high in palmitic acid, it is not the only fat we eat.

My brain fog and energy level both improved when I stopped eating gluten 6 years ago. I was so ill I thought I would have to give up working and try to get on disability. In the beginning, my gluten free diet was not low carb. The next step was getting rid of all grains. I noticed that my thinking was clearer if I avoided all grains. Then I discovered my blood sugar was spiking with carbohydrates. Now I am on a gluten free/grain free/high fat/low carb diet and I feel great. I can't say I have had any "intellectual accomplishments", but I am able to continue working as a nurse where I am challenged every day(well, really just 3 days now as I went to half time work as I slip into retirement). I started and run a support group for people with gluten intolerance. We have monthly meetings and I publish a monthly newsletter to help keep people informed of the fast changing world of gluten intolerance.

Anonymous said...

Unless my brain is fried, palmitic acid is what the liver converts excess carbs into.

Like may others my "brain fog" and other symptoms have improved markedly though I've only been doing this for five years: I function best both physically *and* mentally when my BG is in the fours (70 - 90) and my early morning pee niffs slightly of ketones, suggesting my body runs better on fats/ketones rather than glucose. These improvements are constant and no longer rely on snacks to maintain my BG level between meals.

Nick said...


What do ketones smell like?

Anonymous said...

Many of you may be too young to remember acetylene lamps, but you may have smelled acetylene in a welding shop: it's a bit like that, or sort of like bitter pear drops, or like acetone only sharper.

Hmmm, high carb diets make researchers lazy and stupid. Discuss . . .

Unknown said...

I am a five year diabetic I am aware of Jenny through blood sugar 101

On diabetes .org uk I ran into alan(alan mentioned that he had run into Jenny so I paid particular attention) read his blog I test on the 1 hr mark. Pure serendipity let me to high fat its amazing you have to adjust meter timing but digestion seem to be on the order of 5 or 6 hours levels barely move from baseline.

Everything I buy is high fat milk cheese sour cream cream hamburger (regular /lean) Personally I think everyone should go high fat.

I noticed no brain fog or cognitive skill lacking I"ve even stopped taking metformin what for everything is fine. I test regularly Hello Jenny

Paul type2 A1c 5.2

Jenny said...


I had the privilege of meeting Alan when he was making a tour around the world a few years ago. He's an utter delight in person.

I'm glad to hear you are doing so well with your dietary changes, too.