Female Amazonian forager-horticulturalists have the same metabolic rate as Korean college students. They both eat mostly starch. Their body fat is Saturated.

The title of “High resting metabolic rate among Amazonian forager-horticulturalists experiencing high pathogen burden” makes it unambiguous as to the authors feelings about why the Tsimane have high metabolic rates. They include this graph to show just how unique the Tsimane are.

I recently wrote about the plunge in American Metabolic rates in women between 1919 and 1986. (All the same things are true in men, it’s just more dramatic in women.) A problem with the older studies is that they don’t control for lean body mass. One can easily make the argument that American women in 1919 just had a lower body fat percentage and that was why women of the same weight had a higher resting metabolic rate (RMR) than in 1986.

But many newer studies measure the fat free mass (FFM) and report the metabolic rate as calories per day per kilogram of FFM (RMR/Kg FFM)​1–10​. This eliminates the variable of body composition since fat is less metabolically active than muscle, brain, gut, immune system, etc. Looked at in this way, the Tsimane are not so special and we don’t have to go looking for reasons to explain away the anomaly.

CountryYearSubjectsSSO g/dAgeBMIRMR/Kg FFM
USA2018Trained Athletes641922.631.4
USA1996Endurance Athletes543119.933.2
Mainland China2016Healthy53722.436.8

I included a range of age groups and people of different activity levels so that we can say things like, “19 year old American female trained athletes have a metabolic rate 13% lower than 45 year old Italian women of normal activity level when you adjust for fat free mass.” Or you could say, “19 year old American female trained athletes have a metabolic rate 20% lower than 21 year old Korean female college students of normal activity level when you adjust for fat free mass.” Or you could say, “Korean college students have metabolic rates 37% higher than American couch potatoes of the same age after you adjust for fat free mass.”

I have been making the argument that 1) metabolic rate is closely related to fat saturation rate and 2) starch eating cultures have very saturated fat. Therefore, 3) starch eating cultures should have high metabolic rates after adjusting for lean mass. The column labelled SSO g/d stands for “soybean plus sunflower oil per capita expressed as grams consumed per day”​11​. (This is a national average, not necessarily indicative of the population being studied and the last year of data available is 2013. Still, that is the best data we have.) As you can see, cultures who consume less than around 25g/day or less of these oils have higher metabolic rates than those who eat more than 50g, even after adjusting for fat free mass. There is something fundamentally different about the metabolism of Americans sucking down soybean oil.

These measurements are taken early in the morning with the subject in a supine position in full relaxation. The only way that someone should have a significantly higher metabolic rate than someone else once you adjust for fat free mass is if that someone is doing something like thermogenesis – burning off calories as heat.

This may go a long way to explain the statement made by the main author of “The China Health Study”, “In the China Study, the least active Chinese consumed 30% more calories than their American counterparts yet their body weight was 20% lower. The excess calories were lost as heat rather than being stored as fat.”

I put a question mark next to the Tsimane consumption of soybean and sunflower oil. This is what we know about their diet: “The Tsimane people live in villages without running water or electricity, and subsist largely on rice, plantains and the starchy root vegetable manioc. Rapid community changes over the last few decades include increased access to store-bought foods and antibiotics.” We know that their metabolic rate actually DROPPED to 39.7kcal/Kg FFM/day after they gained access to store-bought foods. This suggests to me that they now eat some vegetable oil, but it’s unclear how much and it probably hasn’t been long enough to put them into torpor.

Should You Eat All Starch?

That’s kind of complicated. If you’re reading this, you are likely to have a torpid metabolism that will rapidly convert all of the saturated fat you’d make from the starch into unsaturated fat. You have to get out of torpor first.

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21 thoughts on “Female Amazonian forager-horticulturalists have the same metabolic rate as Korean college students. They both eat mostly starch. Their body fat is Saturated.”

  1. Hi Brad,
    Interesting how you have combined the diet to body temperature and basic metabolic rate. It is most convincing when increased food intake and lower stabile weigth + higher metabolic rate are being combined.

    The body can produce de novo glucose and paltitate 16:0. If we accept help from our enzyme elovl6 also “olive oil” and stearate 18:0 can be made de novo. How can it be dangerous to consume starch (poly-glucose) and saturated fats, the very molecules our body produces? Like to harm us, kill us?

    The very low carb and the very low fat diets have been shown to work, either therapeuticly or for weight loss. I guess you have added to that, that a combination of starch and saturated fat works as well, but poly-unstable fats in combination to starch/ fruit/sugar is a slow fast lane to demise. Weston A. Price saw /concluded this during his trips… Well, massive pufa-6 intake has been possible for less than 150 years.

    One pork study of elovl6 and fatty acids for your reference https://gsejournal.biomedcentral.com/articles/10.1186/s12711-015-0111-y

  2. Brad,
    Regarding your parting comment, “That’s kind of complicated. If you’re reading this, you are likely to have a torpid metabolism that will rapidly convert all of the saturated fat you’d make from the starch into unsaturated fat. You have to get out of torpor first”.
    So, should I interpret that to mean that until one gets out of torpor, with the aid of barberine, fish oil, SA butter, SO, etc., that it may best best to minimize carbs and make the fats as high in SFA, and as low in Omega-6 PUFAs, as possible? In other words, go light on the croissants, but high on the SFA, until metabolism revs up more?
    And do you have a view on protein? I know you’ve referenced populations with diets that were relatively low in protein having people that were quite lean, but if I enjoy protein is it ok as long as it’s low Omega-6 PUFA….I.e. skinless chicken breasts, tuna, beef?

    1. I just bought several pints of heavy cream as an experiment to try to do just that. 1 pint per day, either as a mousse of with protein powder.

      I’m also buying the leanest ground turkey possible and adding in cream cheese and sour cream for the saturated fats.

      My body temp is consistently between 96.7 and 98.1 degrees. I’m not sure how accurate these thermometers are that are taking my temperature everywhere I go.

    2. Brad Marshall

      It’s unclear to me if starch is “bad” in a torpid state or just that it won’t have the effect it has if you were brought up in a starch eating culture that had no access to vegetable oils. I’m a little agnostic to macro ratios these days. But you could be right.


  3. Brad,
    A bit off topic here, but I saw this article on Mercola this morning which had the following comment regarding ROS and was curious as to your thoughts:

    As explained by Dr. Robert Lustig:

    “We have a metabolic burden of reactive oxygen species (ROS) that are doing damage if you can’t quench them. That’s why we have antioxidants in our body — glutathione, vitamin E — [they’re] basically the sink for those reactive oxygen species. The fact of the matter is our mitochondria are making ROS every single minute of every single day.

    It is a normal byproduct of metabolism. The point is we’re supposed to be able to quench them. You can only quench them if you get the antioxidants into you.

    The problem is as soon as you’ve taken the germ out of the grain kernel, you’ve basically reduced your antioxidant consumption by tenfold. So, we are antioxidant deficient because of food processing, which then leaves us vulnerable to the ravages of ROS from multiple sources including our own mitochondria.”

    I’m relatively new to the site and am thoroughly fascinated by the concepts you’re putting forth. I’ve been trying to help my wife ‘unlock’ her ability to burn fat for years now, and am hopeful this works. She’s been trying keto for quite some time now, so I hope putting the focus on the ‘types’ of fat is the magic needed.


  4. I have found that Astaxanthin 12mg is better at raising basal temperature and fasting glucose lowering than Berberine. It’s interesting how one’s temperature rises during the day and seems highest just prior to bedtime. Does anyone here use Astaxanthin and have recommendation for a good product?

    1. That’s good to hear. Using Berberine daily for 6 weeks destroyed my digestion – I am now seriously constipated even though I discontinued it a couple of weeks ago.

  5. Excellent article. My first thoughts on the other ones you wrote on this topic was are we adjusting for FFM as body fat goes up because that may account for the effect. You’ve addressed this perfectly here.

  6. I’m not saying berberine and strenuous oil is making me fatter, but after a moth using both as recommended, I have not dropped any weight. Some clothes I haven’t worn in a year no longer fit.

  7. The only way I have been able to steadily lose on high saturated diet is if I keep carbs under 75 grams. I was eating 1500 calories and keeping carbs under 50 and I was still gaining and feeling tired constantly. Now I can eat 1750-2k calories and lose if I keep carbs under 75 grams, so yes carbs matter (for me at least).

    1. Firebird7479

      I did my best on The Zone Diet. Back then it was considered high protein, low carb. Now it’s considered moderate protein, high carb by the low carb industry. I lost no weight at all on low carb and steadily gained over the years. I gave up breads, pastas, potatoes, etc. with very little to show for it.

      I think I am going to that but modify it to fall in line with the Perfect Health Diet and Fire in a Bottle. I cannot, however, eat croissants. They do something to my gut.

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