Short-Term Effects of Fat, Protein and Carbohydrate on Cognition: Fat Best

A German study published in 2001 measured the effect of starkly different breakfasts (all fat, all protein, or all carbohydrate) on cognition during the next hours. Participants (17 men in their 20s) ate the same packaged dinner at home and next morning came to the lab and ate different breakfasts. All of the breakfasts were “cream-like” and all contained 400 calories. The design was relatively sophisticated. Practice effects were reduced by giving considerable practice with the tests before the main measurements began. Brain tests included a simple reaction time task, a choice reaction time task, and a “combi-test” in which the subject does two things at once that provides six measures of performance. One set of tests took 15 minutes. The tests were done once/hour for 3 hours after the breakfast.

The simple reaction time test showed no difference between the breakfasts. The choice reaction time test and the combi-test did show differences: The all-fat breakfast was better. The improvement produced by the fat breakfast compared to the other two breakfasts was clearest about two hours after the breakfast.

EMG (brainwave) measurements showed no differences between the breakfasts.

These results agreed with previous work.

Cunliffe et al. (1997) reported that a pure fat meal did not increase reaction times in contrast to carbohydrate ingestion when measured hourly for 4 h after the meal. In our study, fat ingestion even improved reaction times compared with baseline. Our subjects scored best for all tasks of the combi-test after the fat meal. This finding is in line with the higher accuracy of a focused attention task after a high-fat meal compared with a low-fat meal reported by others (Smith et al. 1994).

The “fat” breakfast in this study was 25% soybean oil (high in omega-6), 25% palm oil (high in saturated fats) and 50% cream (high in saturated fats). I have not compared omega-6 to nothing but I suspect it would produce worse results, given that olive oil appears worse than nothing. So I suspect that the improvement due to fat was due to the palm oil and cream. I concluded, based on evidence that I and others collected, that butter (high in saturated fats) improves arithmetic speed. I usually ate 30 g (= 2 tablespoons = 270 calories) of butter twice/day. Close to the dosage of this experiment. The timing of the effects I saw (sharp improvement from one day to the next) is consistent with a change that happens within 2 hours.

These results, which I didn’t know about until recently, support my earlier conclusions about butter. My measurements cost almost nothing whereas this experiment must have cost thousands of dollars ($400/subject?) plus hundreds of hours of researcher time. Maybe I should compare cream and butter. Cream has advantages. Mark Frauenfelder suggested using cream to make yogurt. Superfood!

A more recent study found saturated fat consumption correlated with cognitive decline. It was a survey, however, with many differences between the groups being compared. I trust experimental evidence much more than survey evidence.

22 Responses to “Short-Term Effects of Fat, Protein and Carbohydrate on Cognition: Fat Best”

  1. Vic Says:

    Olive oil is only 10% Omega-6, it’s mostly mono-unsaturated fat.

  2. Jim Purdy Says:

    I don’t understand why doctors have so much fear of essential brain building blocks like fats and cholesterol, and why they promote statins that interfere with these brain functions.

    Seth: Might be the same reason that tonsillectomy surgeons ignore — or don’t even know — that tonsils are part of the immune system.

  3. Alex Chernavsky Says:

    Seth, can you speculate about why the simple reaction-time test was apparently less sensitive than the other two tests? And does this study change your view of the overall usefulness of the simple reaction-time test as a measure of cognitive function?

    Seth: The simple RT test was less sensitive because it involves less mental processing. No, this study does not change my view of the value of simple RT as a measure of cognitive function. I have never believed it is a good measure of that.

  4. MikeW Says:

    Interesting result, but I wish they had tested past that 3-hour window. Almost all of palm oil’s saturated fats, and about 2/3rds of cream’s, are the longer-chain c16:0 and c18:0. These don’t peak in the bloodstream til about 5 hours after consumption. Short- and medium- chain fats (found in dairy and coconut/palm kernel oil) are metabolized more quickly, and peak in about 2 hours.

    So, to me, all the 3-hour test shows is that c14:0 and shorter saturated fat consumption can improve mental performance. It doesn’t say anything about c16:0/c18:0, the predominant saturated fats in meat, eggs and nuts.

  5. Matt Says:

    Another thing you could try is beef tallow versus butter. The fatty acid profiles are very similar with at least one notable difference: butter (and cream) have butyric acid, while tallow does not.

  6. gwern Says:

    One of the downsides of yogurt is that the low-fat craze has gotten there, as well, and it’s easy to remove all fat from yogurt.

    Like my grocery store – if I want Greek yogurt, I can take my choice of 3 delicious varieties… all zero fat.

  7. Nick Says:

    Currently there are two routes to do science:

    1. research institutions (the vast majority of the research)

    2. the n=1 self-experimenter (a select minority; people like you, Seth)

    Yesterday I was struck with an idea: Why not crowd source science? Set up a website where people from across the globe can participate in worthwhile science projects. It could encompass all sorts of subjects, from psychology to nutrition to collaborative physics. People can join in experiments they feel to be promising and interesting.

    Just as Wikipedia overhauled the encyclopedia, this website could revolutionize science.

  8. Nick Says:

    http://en.wikipedia.org/wiki/Citizen_science

    Perfecting a model of citizen science is what I’m talking about.

  9. Ed M. Says:

    I make my yogurt with heavy whipping cream exclusively.

    Tastes great.

    –Ed

  10. David Johnston Says:

    Ed – Share your heavy cream yoghurt recipe!

  11. Paul N Says:

    Not sure what Ed’s recipe is, but I’m happy to share mine.

    Buy the best, and freshest, whipping cream you can get. Organic is best, and without any additives like carageenan gum.

    Buy some plain kefir (not yogurt) -you’ll have to look for it- but it’s worth it – and you only have to buy it once.

    Add kefir to the cream in a ratio of about 1:5, place in a glass jar/bottle and leave somewhere at room temp (countertop, cupboard above fridge, etc) for 24hrs. This is why you use kefir instead of yogurt – it works at room temp, not 35-40C like yogurt – and is a much stronger mix of probiotics.

    After 24hrs, put the cream back in the fridge and leave for three days. It is then ready to eat, is as thick as whipped cream, and has a slight tangy taste. you can flavour with vanilla, stevia, honey, coffee, brandy, etc

    You can also make cultured butter from it at this point. Just half fill a jar with your kefir-ed cream, leave out to warm to room temp (or sit in a warm water bath if you can’t wait), and then just shake the jar end to end. Normally takes about three minutes for the cream to break, but longer if it is cold.
    You can then pour off the buttermilk, and use that for pancakes or other (gluten free) baking.

    Wash the butter with cold water until is clear and store. Salt it if you like.

    Not only will this be the best butter you ever tasted, it is probably the healthiest, and possibly cheapest too.

    The three minutes of shaking is worth it and makes and ideal pre-dinner mini workout, or to get the blood going in the morning!

  12. Txomin Says:

    Thanks for the recipe, Paul.

  13. L Says:

    Perhaps obese Americans should increase intake of saturated fats. It will surely decrease cancers, heart disease, stroke, etc!! Who’s willing to do n=1 on this? Let me know! We can publish this together!!!!

  14. dearieme Says:

    O/T, but I thought you might be amused by this from this morning’s Telegraph, by the excellent James Le Fanu.

    Finally, a cautionary reminder of the confusion that can arise when medication causes the symptoms of the condition it is intended to treat. Here, a lady from Worcester writes to tell of the ever-more intrusive symptoms of her long-standing anxiety, where she would become fixated on the fine detail of things – dots on carpets, small stones, leaves, people’s eyebrows, and so on.
    Her doctors and the community psychiatric nurse were sympathetic, but had no suggestions as to what to do. Then late last year, her anti-anxiety medication Stelazine became unobtainable in Britain – since when her fixation episodes have vanished, so far never to have returned.

  15. L Says:

    why do stupid people take meds and get stupider???!!

  16. David Johnston Says:

    L: I’m certainly doing a n=1 study on increased saturated fat intake. It’s improved my numbers, but so did a low fat diet and exercise in the Look Ahead study. When I die, I’ll let you know.

  17. RonBoyd Says:

    Seth, I don’t know what this sentence means. Please explain.

    “I have not compared omega-6 to nothing but I suspect it would produce worse results, given that olive oil appears worse than nothing. ”

    Seth: In Expt A I compared flaxseed oil to olive oil. In Expt B, I compared flaxseed oil to nothing. Expts A and B were very similar. Comparing olive oil in Expt A to nothing in Expt B, olive oil was worse than nothing.

  18. David Johnston Says:

    So ELOO worked for weight loss in the Shangri La diet, but not for achieving fast speeds in cognitive speed tests. Is that a correct interpretation of your data?

    Seth: Yes.

  19. L Says:

    thank u mr david johnston.

  20. Evelyn M. Says:

    To make yogurt I use 3 1/2 cups whole milk, 1/2 cup heavy cream and four tablespoons of dried whole milk powder (which adds protein as well as cream). It works very well. If you want to make “Greek yogurt” – in Persian it is called mast-e-keesayee (or bagged yogurt) – just drain the yogurt through cheesecloth in the fridge until it becomes the texture you prefer.

  21. L Says:

    @ Evelyn m : what do you do after all the milk and cream are put together? Do you always use a cheesecloth for all types of yogurt u make??

  22. Evelyn M. Says:

    Hello, L. Thanks for reading my comment. I heat the milk and cream mixture to about 125 degrees F in a microwave and then put it in a yoghurt maker that keeps a very low, steady temperature. I usually leave it there for about 24 hours before moving it to the refrigerator. Most of the time I use the yogurt as is, I only make the strained version for special occasions, such as Persian New Year in March or Christmas.

    By the way, I wonder why sour cream hasn’t been mentioned. Sour cream is a wonderful product, pretty well unique to the U.S. (at least I never found it for sale in England). One can easily find a brand that doesn’t have any additives, such as Daisy, and it makes just about everything taste better.