4

votes

Does a High-fat diet impair cognitive function?

Answered on August 19, 2014
Created January 24, 2012 at 1:41 PM

Hi everyone. I'm new to PaleoHacks as I user but I've been reading a lot of your posts over the past several months. Thank you for all of your research and anecdotes which coupled with some Google Scholar hunting guided me in eventually adopting an LCKD which has helped me loose wait, attain higher concentration levels at work and NOT fall asleep at my desk between meals. I don't keep a diet journal :(, but I think me diet might high in fat: lots of butter, heavy creams, cheeses, fatty meats, coconut oils, etc.

Sorry for the rather controversial question, but this is reference to a cognitive-dissonance-challenging study I found this morning A high-fat diet impairs cardiac high-energy phosphate metabolism and cognitive function in healthy human subjects (http://www.ajcn.org/content/93/4/748.abstract). I was almost worried until I saw it was 5d study. Nonetheless, has anyone read the full text to the study or have any other insights to share? I feel my own anecdote following several months of adhering to the diet resolves to me personally any fear of cognitive impairment, but cardiac function is something I don't know how to assess as well; so there's still a small pin of worry in me from this.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on February 17, 2012
at 01:46 AM

Inuits aren't in ketosis, search google or paleohacks and you will find the article. Basically Inuits are adapted to lower carbohydrate levels and don't enter full blown ketosis.

D6304567ada7ac5e8c6f4e5902270831

(90)

on February 16, 2012
at 06:21 PM

Cliff, thanks for your answer. I think however that given the human is capable of producing all the glucose it needs through gluconeogenesis, the brain's glucose needs might not be a valid argument against ketosis. Indeed it's not rigorously tested (I don't see we'll ever see a RC trial for lifelong ketosis), lots of variables, etc., but we know of several groups of people studied (the Innuit, as you mention) that have lived virtually their whole lives in ketosis. What are the causes of death though of the Innuit? Off the cuff, I would imagine exposure or starvation were common.

D6304567ada7ac5e8c6f4e5902270831

(90)

on January 26, 2012
at 03:28 PM

Cody. That's interesting. Thanks for this anecdote. I do similar work, so knowing this helps one person in a similar role reassures me some.

D6304567ada7ac5e8c6f4e5902270831

(90)

on January 26, 2012
at 03:25 PM

Wow. Just wanted to say real quick: What an awesome community!! :-) Never expected this many responses (with citations!) so soon. Really great insights and discussions which I hope to follow up on soon! Busy now with a big project at work but will return to this.

D6304567ada7ac5e8c6f4e5902270831

(90)

on January 26, 2012
at 03:24 PM

Wow. Just wanted to say real quick: What and awesome community!! :-) Never expected this many responses (with citations!) so soon. Really great insights and discussions which I hope to follow up on soon! Busy now with a big project at work but will return to this.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on January 25, 2012
at 01:08 PM

Te inuit ate thyroid as well, if you don't eat thyroid your diet is vastly different than theirs.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on January 25, 2012
at 01:06 PM

http://wholehealthsource.blogspot.com/2008/07/mortality-and-lifespan-of-inuit.html "Excluding infant mortality, about 25% of their population lived past 60. Based on these data, the approximate life expectancy (excluding infant mortality) of this Inuit population was 43.5 years" IF you only want to live to 44 I guess the inuit diet is ok assuming you are even adapted to it like they are.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on January 25, 2012
at 01:03 PM

@heather- google scholar "Fatty acid tissue composition and diabetes" @cody- Your the one who can't even comprehend what travis is saying.

77877f762c40637911396daa19b53094

(78467)

on January 25, 2012
at 04:08 AM

Travis and Cliff, thanks for providing evidence that high carb diets may lower cognitive function! Bravo!

77877f762c40637911396daa19b53094

(78467)

on January 25, 2012
at 04:07 AM

Travis, you do realize you are insinuating that all human beings living on marginal tundra lands are stupid. I'm pretty sure you just offended a very large group of people...

Cbb1134f8e93067d1271c97bb2e15ef6

on January 24, 2012
at 11:37 PM

http://drcate.com/can-arterial-disease-be-reversed/

Cbb1134f8e93067d1271c97bb2e15ef6

on January 24, 2012
at 11:35 PM

http://drcate.com/how-much-carbohydrate-do-you-need-to-eat-per-day/

Cbb1134f8e93067d1271c97bb2e15ef6

on January 24, 2012
at 11:33 PM

http://www.meandmydiabetes.com/2011/04/14/steve-phinney-low-carb-preserves-glycogen-better-than-high-carb/

Cbb1134f8e93067d1271c97bb2e15ef6

on January 24, 2012
at 11:31 PM

http://www.sott.net/articles/show/238813-Low-Carb-Living-with-Dr-Stephen-Phinney

C8b2136ef95ba6aac211825ff38cc0e9

(971)

on January 24, 2012
at 10:33 PM

I found the first article very informative. I feel my SSRI's caused me problems over time and some supplements I have tried "for depression" have caused bad reactions for me as far as concentration and energy level. Do you have any articles or info regarding increased PUFA concentration and release from tissue? I guess my pig foot broth is a good thing...

Ccacf7567273244733bc991af4ac42ed

(5198)

on January 24, 2012
at 08:13 PM

Your ancestors followed the animals but refrained from eating them thanks to the lush grasslands? Clever people. I suppose that means you think the Inuit (amongst others) are pretty stupid.

Medium avatar

(39821)

on January 24, 2012
at 07:14 PM

I dunno about your ancestors, but mine weren't so stupid as to hang out in marginal tundra lands when they could just follow the animals southward into more lush landscapes. The idea that the Earth was a total ice planet is preposterous.

A968087cc1dd66d480749c02e4619ef4

(20436)

on January 24, 2012
at 06:20 PM

So, by your own experience, you have HIGHER levels of concentration at work. Doesn't that at least hint that this study is terribly wrong?

77877f762c40637911396daa19b53094

(78467)

on January 24, 2012
at 03:58 PM

Cliff may have been deposited here by aliens. It would explain a lot, actually. Just giving you a hard time, Cliff. ;)

Ccacf7567273244733bc991af4ac42ed

(5198)

on January 24, 2012
at 03:49 PM

All our ancestors surely? Well, I'm pretty sure mine were, I wouldn't want to speak for you of course. I'll run through the science for you though. Hypothesis - humans survived the ice age. Method - Observe the existence of a human some time after the ice age. Conclusion - hypothesis is confirmed.

77877f762c40637911396daa19b53094

(78467)

on January 24, 2012
at 03:30 PM

Looking over the study, they looked at blood sugar levels and they looked at ketones in the urine. Once one is adapted to ketones, they do not spill into the Urine. And I suspect that the high levels of Omega 3 helped them to maintain their glucose sensitivity. That study doesn't prove that the eskimos were not in ketosis. It proves that they were extremely well adapted to ketosis. Proving long term ketosis is NOT dangerous. They also showed that in eating 4 to 8 pounds of fatty meat daily doesn't not negatively impact health.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on January 24, 2012
at 03:04 PM

The Inuits don't enter ketosis as they are physically adapted to the diet, http://paleohacks.com/questions/14057/were-eskimos-better-adapted-to-very-low-carb-diet#axzz1kO88gZRw . @primaldanny Who was around during the ice age to test the variables? Show me the science, would love to see it.

Ccacf7567273244733bc991af4ac42ed

(5198)

on January 24, 2012
at 02:45 PM

I thought we tested the necessary variables in the last ice age as well, we seemed to do ok. And I thought we even had some actual science that glucose wasn't the best fuel for (most of) the brain?

77877f762c40637911396daa19b53094

(78467)

on January 24, 2012
at 02:37 PM

cliff, the inuit traditional diet is ketogenic a large part of the year, by definition. I think that proves beyond a reasonable doubt that longer term ketosis is fine.

  • D6304567ada7ac5e8c6f4e5902270831

    asked by

    (90)
  • Views
    2.8K
  • Last Activity
    1521D AGO
Frontpage book

Get FREE instant access to our Paleo For Beginners Guide & 15 FREE Recipes!

7 Answers

best answer

4
A968087cc1dd66d480749c02e4619ef4

(20436)

on January 24, 2012
at 06:18 PM

I want to answer this question, but my brain is like, all cloudy. Must be the eggs, coconut oil, almonds and chocolate I had for lunch.

Seriously, 75% of calories as fat (what kind we don't know) is a very low carb/ketogenic type of diet. Ever heard of the "low carb flu"? The first week or two, people tend to be lightheaded, headachey, wonky or worse. They performed worse on cognitive function tests? No duh!

I sometimes eat that way, but I add some carbs when my hands/feet start getting cold. (I normally have overly hot feet/hands and rarely wear a coat unless it drops below 30.)

Nobody said paleo has to be 75% fat! Ketogenic diets can be useful for certain medical conditions, but paleo doesn't have to be ketogenic. Just eat realz fud! Eat some meat, eggs, some fruit and vegeetabulz and other real things. It's incomprehensible that eating in line with our evolutionary past would be unhealthy.

Also, the 9% reduction in PCr/ATP could probably be explained by the fact that the heart loves to burn ketones! Other sources of energy would HAVE to be downregulated. This is not an indication of impending heart failure (as it might be for someone not generating tons of ketones). Either the researchers are stupid or (more likely) intentionally trying to discredit ketogenic diets. Very unethical IMHO.

Oh! This study was paid for by the British Heart Foundation. They like to give out healthy eating advice like this:
http://www.bhf.org.uk/heart-health/prevention/tips-for-parents.aspx

"Eating breakfast helps children stay alert during lessons and energised throughout the day. Try wholegrain cereals topped with low fat yoghurt and fruit to help them reach their five-a-day.

"Pack lunchboxes with healthy eating options, like pittas and bagels filled with tuna and sweetcorn. Low-fat yoghurt and a small packet of dried fruits will satisfy a sweet tooth.

"For after-school snacks make sure there are fruit and nuts to hand. Beans on toast or mashed banana sandwiches are healthy ideas for really hungry youngsters."

The usual memes of low fat, healthy whole grains, 5 a day, avoid red meat, blah, blah, blah. A bunch of corporatist shills, if you ask me. (Did you ask me?)

4
E5c7f14800c5992831f5c70fa746dc5c

(12857)

on January 24, 2012
at 02:30 PM

Based on my research and reading ray peat If the FFA's are saturated most of the harmful effects can be mitigated. The problem is when people are coming from a SAD and have a high concentration of PUFA in there tissue, when the PUFA is released as FFA's they have many negative metabolic consequences. This is most likely what is happening in the study but I can't be 100% sure.

http://raypeat.com/articles/aging/tryptophan-serotonin-aging.shtml

Personally I wouldn't do a ketogenic diet long term, too many untested variables and some info that it might not be the best in regards to immune function.

jem.rupress.org/content/98/2/145.full.pdf

http://www.ncbi.nlm.nih.gov/pubmed/8649223

http://www.ncbi.nlm.nih.gov/pubmed/10438318

Your brain runs on glucose primarily as well so it only makes sense its gonna run the best on its preferred fuel.

Ccacf7567273244733bc991af4ac42ed

(5198)

on January 24, 2012
at 02:45 PM

I thought we tested the necessary variables in the last ice age as well, we seemed to do ok. And I thought we even had some actual science that glucose wasn't the best fuel for (most of) the brain?

Ccacf7567273244733bc991af4ac42ed

(5198)

on January 24, 2012
at 03:49 PM

All our ancestors surely? Well, I'm pretty sure mine were, I wouldn't want to speak for you of course. I'll run through the science for you though. Hypothesis - humans survived the ice age. Method - Observe the existence of a human some time after the ice age. Conclusion - hypothesis is confirmed.

77877f762c40637911396daa19b53094

(78467)

on January 24, 2012
at 02:37 PM

cliff, the inuit traditional diet is ketogenic a large part of the year, by definition. I think that proves beyond a reasonable doubt that longer term ketosis is fine.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on January 24, 2012
at 03:04 PM

The Inuits don't enter ketosis as they are physically adapted to the diet, http://paleohacks.com/questions/14057/were-eskimos-better-adapted-to-very-low-carb-diet#axzz1kO88gZRw . @primaldanny Who was around during the ice age to test the variables? Show me the science, would love to see it.

Medium avatar

(39821)

on January 24, 2012
at 07:14 PM

I dunno about your ancestors, but mine weren't so stupid as to hang out in marginal tundra lands when they could just follow the animals southward into more lush landscapes. The idea that the Earth was a total ice planet is preposterous.

77877f762c40637911396daa19b53094

(78467)

on January 25, 2012
at 04:08 AM

Travis and Cliff, thanks for providing evidence that high carb diets may lower cognitive function! Bravo!

77877f762c40637911396daa19b53094

(78467)

on January 24, 2012
at 03:58 PM

Cliff may have been deposited here by aliens. It would explain a lot, actually. Just giving you a hard time, Cliff. ;)

C8b2136ef95ba6aac211825ff38cc0e9

(971)

on January 24, 2012
at 10:33 PM

I found the first article very informative. I feel my SSRI's caused me problems over time and some supplements I have tried "for depression" have caused bad reactions for me as far as concentration and energy level. Do you have any articles or info regarding increased PUFA concentration and release from tissue? I guess my pig foot broth is a good thing...

77877f762c40637911396daa19b53094

(78467)

on January 25, 2012
at 04:07 AM

Travis, you do realize you are insinuating that all human beings living on marginal tundra lands are stupid. I'm pretty sure you just offended a very large group of people...

77877f762c40637911396daa19b53094

(78467)

on January 24, 2012
at 03:30 PM

Looking over the study, they looked at blood sugar levels and they looked at ketones in the urine. Once one is adapted to ketones, they do not spill into the Urine. And I suspect that the high levels of Omega 3 helped them to maintain their glucose sensitivity. That study doesn't prove that the eskimos were not in ketosis. It proves that they were extremely well adapted to ketosis. Proving long term ketosis is NOT dangerous. They also showed that in eating 4 to 8 pounds of fatty meat daily doesn't not negatively impact health.

Ccacf7567273244733bc991af4ac42ed

(5198)

on January 24, 2012
at 08:13 PM

Your ancestors followed the animals but refrained from eating them thanks to the lush grasslands? Clever people. I suppose that means you think the Inuit (amongst others) are pretty stupid.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on January 25, 2012
at 01:08 PM

Te inuit ate thyroid as well, if you don't eat thyroid your diet is vastly different than theirs.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on January 25, 2012
at 01:03 PM

@heather- google scholar "Fatty acid tissue composition and diabetes" @cody- Your the one who can't even comprehend what travis is saying.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on January 25, 2012
at 01:06 PM

http://wholehealthsource.blogspot.com/2008/07/mortality-and-lifespan-of-inuit.html "Excluding infant mortality, about 25% of their population lived past 60. Based on these data, the approximate life expectancy (excluding infant mortality) of this Inuit population was 43.5 years" IF you only want to live to 44 I guess the inuit diet is ok assuming you are even adapted to it like they are.

D6304567ada7ac5e8c6f4e5902270831

(90)

on February 16, 2012
at 06:21 PM

Cliff, thanks for your answer. I think however that given the human is capable of producing all the glucose it needs through gluconeogenesis, the brain's glucose needs might not be a valid argument against ketosis. Indeed it's not rigorously tested (I don't see we'll ever see a RC trial for lifelong ketosis), lots of variables, etc., but we know of several groups of people studied (the Innuit, as you mention) that have lived virtually their whole lives in ketosis. What are the causes of death though of the Innuit? Off the cuff, I would imagine exposure or starvation were common.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on February 17, 2012
at 01:46 AM

Inuits aren't in ketosis, search google or paleohacks and you will find the article. Basically Inuits are adapted to lower carbohydrate levels and don't enter full blown ketosis.

4
77877f762c40637911396daa19b53094

(78467)

on January 24, 2012
at 02:21 PM

Search Paleo Hacks and the all mighty Google. Seth Roberts. Math. Butter.

I suspect it depends on the type of fat, but butter has been shown to increase cognitive function, and I find being in a state of ketosis helps my brain work better. Of course, I pair my ketosis with coffee, which may or may not have an impact.

If it makes any difference, I'm a computer programmer by trade, and a pretty darn good one, so my brain HAS to work. My livelihood depends on it. Low carb/high fat diets work great for me.

Also, regarding cardiac function, I've read that the heart is 17% more efficient when running on ketones.

EAT YOUR FAT == LIVE LONG AND PROSPER

D6304567ada7ac5e8c6f4e5902270831

(90)

on January 26, 2012
at 03:28 PM

Cody. That's interesting. Thanks for this anecdote. I do similar work, so knowing this helps one person in a similar role reassures me some.

3
E2b72f1912f777917d8ee6b7fba43c26

(2384)

on January 24, 2012
at 02:23 PM

A high fat diet (of course no soy bean oil etc., there's no way this could be healthy) leads automatically to lower carb consumption. And with a low carb intake, ketosis becomes likely.

But now there are several studies out there that show the neuroprotective properties of ketone bodies.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2649682/

Very unlikely this could be brain damaging. Plus, I don't think evolution wants us to get stupid from depleting our body fat storages...

EDIT: maybe they have testet them during keto adaption, in my experience the first 3 weeks are brain-standby-mode

2
Ccacf7567273244733bc991af4ac42ed

on January 24, 2012
at 02:40 PM

I don't have the full text, but I can imagine what would be contained. It's simply incredibly difficult to draw meaningful conclusions from trying to control human diets for a short period of time.

2
76d70438d2442d21206b8e5528d23d23

on January 24, 2012
at 02:27 PM

I wish I could comment on more of the details, but I can tell you, just from the abstract, that they've been sloppy with their terminology: their definition of "high fat/low carb" probably isn't mine, and may not be yours.

They say that the "high fat" diet they used got 75%(!) of the calories from fat. That leaves you with 25% to split betw/the proteins and carbs, so I'm betting that the carbs came out at 10% or less.

And if that's the case, that's not just low carb: that's a very low carb diet; there's a big difference. (And I really can't see them giving more carbs than protein, can you?)

So it looks like they haven't really established that their results hold true for what most folks call "low carb/high fat," just that there's a concern on Very High Fat/Very Low Carb diets.

I'm not a dr., and this is not medical advice, but if your fat intake--and, more importantly, your carb intake--isn't as out of balance as their "high fat" diet, I'm thinking you're probably okay.

1
F38f19b6ec74b2c6bf49531fe5dae567

on January 24, 2012
at 07:06 PM

From my own experience of food and cognitive test tracking, I perform significantly better when I eat a higher fat diet, which does not mean ZC or even VLC. I've only been tracking for the last month and the fat I've "supplemented" with is lard. My results have been similar to Seth Roberts'.

Answer Question


Get FREE instant access to our
Paleo For Beginners Guide & 15 FREE Recipes!