Category: nutrition

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

Seth Roberts22 Comments

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.

Assorted Links

Seth Roberts6 Comments

 

Thanks to Anne Weiss and Dave Lull.

Fear of Food: “The Hubris of Experts”

Seth Roberts5 Comments

At the end of Fear of Food: A History of Why We Worry about What We Eat by Harvey Levenstein (2012), an historian at McMaster University, the author summarizes what he has learned:

During the course of writing this book, I have often been asked what lessons I personally draw from it. . . . The hubris of experts confidently telling us what to eat has often been well-nigh extraordinary. In 1921, for example, the consensus among the nation’s nutritional scientists was that they knew 90% of what there was to know about food and health.

Yeah. Two questions for an expert giving advice, especially apocalyptic advice (“You’ll die if you don’t . . . “): 1. What fraction of what there is to be known on your subject do you know? 2. May I quote you?

When I was a freshman in college, I went to hear a talk (off campus) about the chance of life elsewhere in the universe (or was it the galaxy?). The speaker multiplied a bunch of numbers together and came up with an estimate. “What’s the error in that estimate?” I asked. The speaker had no answer. He didn’t know. It’s essentially the same thing.

More About Pork Fat and Sleep

Seth Roberts22 Comments

One day in 2009, I ate a large amount of pork belly (very high in fat — pork belly is the cut used to make bacon). That night I slept an unusually long time. The next day I had more energy than usual. This led me to do an experiment in which I ate a pork belly meal (with lots of pork belly, about 250 g) on some days but not others. I compared my sleep after the two sorts of days. I kept constant the number of one-legged stands I did each day because that has an effect. During the first half of the experiment I kept this constant at 4; during the second half, at 2. I originally posted the results only from the first half.

Now I’ve analyzed the results from both halves. Here are ratings of how rested I felt when I woke up, on a scale where 0 = 0% = not rested at all and 100 = 100% = completely rested.

The two halves were essentially the same: pork belly produced a big improvement. Here are the results for sleep duration.

No clear effect of pork belly in either half of the experiment.

The main thing I learned was that pork fat really helps. The effect is remarkably clear. With micronutrients, such as Vitamin C, the body has considerable storage. It may take months without the nutrient to become noticeably deficient. With omega-3, which is between a micronutrient and a macronutrient, my experiments found that it takes about two days to start to see deficiency. With pork fat there seems to be no storage at all. I needed to eat lots of pork fat every day to get the best sleep. That repletion and depletion are fast made this experiment easy. How curious we are so often told animal fat is bad when an easy experiment shows it is good, at least for me.

American Dietetics Association Tries to Outlaw Competition: More

Seth Roberts1 Comment

Michael Ellsberg has written another fascinating article about how the American Dietetics Association is trying to make it illegal to compete with their members — that is, make it illegal to give nutritional advice without board certification. (His earlier article.) State boards have threatened several bloggers with jail if they continue to provide nutritional advice.

Thanks to Dr. B G.

DIY Medicine: Sinus Infections Caused by Wheat Gluten

Seth Roberts9 Comments

Five years ago programmer and author David Kadavy suffered from constant sinus infections. The doctors he had seen about it hadn’t helped: “They tended to test me for environmental allergies, stick a camera up my nose, and ultimately prescribe some bullshit allergy medication that didn’t work.” What did work:

One day I was reading an old book on holistic medicine. Of course, the first thing I wanted to know was how could I prevent being constantly congested. The book said that foods such as wheat, meat, and dairy often contributed to excess mucous production – and thus, sinusitis. I was miserable, and clearly willing to try anything, so I cut out all three of those things the very next day.

Within two days, the difference was incredible. My head had cleared up, I had boundless energy, and other problems – such as a patch of eczema that I had on my eyelid for years – all cleared up. . . . Through a bit of experimentation I was able to place the blame for my sinus woes (and that eczema thing) on wheat. . . . Not only did the experience have me looking at food differently, it also had me looking at medicine differently. How could I see so many GPs, allergy specialists, ENT [ear nose and throat] specialists, and dermatologists without a single one of them saying “you know, you should look at your diet?”

Yes, how could that be? And, to paraphrase Alex Tabarrok, what else are they missing?

Thanks to Melissa McEwen.

How Low Blood Sugar is Too Low? New Evidence

Seth Roberts17 Comments

Some people avoid all carbs (that is, all bread, pasta, rice, etc.). Others advocate “safe starches”. No doubt wheat can be dangerous — witness celiac disease (associated with a genetic difference). But I have noticed clear improvements in brain function (measured by arithmetic speed or something similar) after eating something sweet, such as pudding. None of this, unfortunately, helps answer the question: how low blood sugar is too low?

A new study makes more plausible the idea that really low levels of carbs may be bad for you:

A nested case-control study data set was generated from the cohort-study data set (n = 4140 type 2 diabetic outpatients) by sampling controls from the risk sets. Cases (n = 427) were compared with an equal number of controls chosen from those members of the cohort who were at risk for the same follow-up time of the case, matched for age (±3 years), sex, body mass index (BMI) (±2 kg m(-2)), duration of diabetes (±5 years), and Charlson’s Comorbidity Score (CCS) (±1). The main predefined analysis was the comparison of cases and controls for proportion of patients with each HbA1c class (<6.5%, 6.5-7.4%, 7.5-8.4% and ≥8.5%). During a mean follow-up of 5.7 ± 3.5 years, 427 deaths were recorded. The lowest risk of death was observed in the HbA1c 6.5-7.4% category; a lower HbA1c was associated with a non-significant trend towards a higher risk. The risk associated with a low (<6.5%) HbA1c was significantly greater in patients who were insulin-treated than in the rest of the sample.

The study is saying that diabetic patients in the HbA1c 6.5-7.4% category do not improve their health when given insulin that lowers their blood sugar even more. Their health may get worse.

Assorted Links

Seth Roberts1 Comment
  • Anti-cancer effect of ginger in mice experiment.
  • Food safety in China.
  • An egregious error in the New York Times. The correction issued by the Times is funny. It says a certain survey, whose results were used, “was not based on a representative sample”. If that is the standard, then no number in the NY Times should be there. They are never based on representative samples. GNP, heights, distances, etc. Plus journalists select what to report — and not in a representative way. Perhaps the paper should consist entirely of blank pages, ads and what are called “thumbsuckers” (fact-free opinion pieces)? I wrote something for Spy that included a representative description. My editor changed it to be funnier.

Thanks to Song Chen and Edward Epstein.

Assorted Links

Seth Roberts4 Comments

Thanks to Alex Chernavsky.