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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52 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. Carlos R Dick Izas

      What happens here is that SCD1 desaturates fats, this makes your fat cells more insulin sensitive and removes the size constraints of such. What happens with carbohydrates besides the lectin damage, is that they spike insulin quite a bit, as your fat cells are very sensitive to it, due to unsaturated fats, they will steal every available Calorie they can; making you fat and leaving you tired as your muscles and brain can’t compete against fat cells fast absorption. However, carbohydrates themselves don’t contribute to the SCD1 problem. Also, the Sterculia oil sold here actually works… Should try.

  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.

      1. I also felt that berberine worsed my constipation, when I used it a couple years back. Not sure exactly how long I used it for, but I’m guessing at least 1-2 months.

        1. It seems this is a common complaint. I’m trying to find time to follow up on this, but preliminary reports back on astaxanthin continue to be positive.


        2. I take berberine daily and my digestion is great. I’m guessing berberine is mixed with fiber and this, contrary to popular belief, is worsening your digestion as many studies have found, you can hear the conference with Dr. Paul Mason about it on YT… I’m on a 95% carnivore diet so I’m definitively not concerned about having too much fiber in my diet. Hope it helps.

        3. Many have reported this. I’ve never had a problem with constipation and it hasn’t bothered me. Consider astaxanthin as a replacement.


    2. Brad Marshall

      Astaxanthin seems very powerful. Thanks for the n=1, very interesting.


  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.

    1. They do work, you are eating too many Calories.
      I found this when I went on vacation and gained 23 pounds while taking my supplements. But it makes sense, berberine helps you metabolizing sugars, incidentally fat cells metabolizing means gaining fat or releasing it. So, your metabolism is working great, fast in and out… Just lower your Calories, as your become more saturated in a few months you will notice you can eat more and not gain weight.

  7. Hey Brad,
    Love your articles, please keep up the great work. When visiting Lancaster County, PA, noticed many lean Amish. They cook with animal fats. Have any studies been done using the Amish?

    1. Not to my knowledge. It’s an interesting thought and observation. I know a lot of Amish. They love ice cream. They also eat at McDonald’s. Many are lean, some are not. It’s a real mixed bag.

  8. 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. 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.

  9. As a former personal trainer, I would watch clients who let say need 2000 cal to maintain weight cut calories to 1800 and lose for 4-6 weeks and then stall. their bodies adjusted to the lowered calories and they now had a new set point of 1800 calories, so to start losing again they went on 1600 calories this time they lose for 3-4 weeks and stall again. This works but its a stupid approach imo. I just had a Eureka moment after reading this article. I lost 38 lbs. since starting TCD Oct of last year. I never had to reduce my calories further than 10% below my maintenance because while I was losing weight my body fat was becoming more saturated and this caused my metabolism to simultaneously speed up, the leaner I got, the more saturated I became and I never slowed my metabolism down from my small 10% deficit. I don’t know of any other way of eating that can do this, and quite frankly nothing has ever changed my body composition so much to the positive. I am eating at maintenance calories for me now of 3100-3200 calories a day and I am still getting leaner while I am not losing weight, or maybe I am losing but more like ounces per week now. Too soon to tell on that front. I dont want to lose any more, but I still eat low PUFA high SA everyday.

    1. I just got weighed this morning and have gained 3 lbs. In the 3 months since I started TCD, I’ve not lost any weight nor have I seen any change in body composition. 🤷‍♂️

      1. Just curious, do you keep track of total calories? What I normally tell the few but growing number of people I have helped is to calculate maintenance calories. Try that estimated level for a week, weigh before, and maintain those calories daily for the week. Then weigh again and make sure its under the same circumstances. Example: Weigh first thing in the morning after using the bathroom. It can make a big difference if you weigh one morning first thing, and another morning forget and get up and drink a glass of water and a cup of coffee then go weigh. You could be 1.5 lbs. heavier just from the fluid alone. Also the amount of clothes matters too. Sorry if this is something you already do, just things to consider.


        1. 2200 calories on average. With TCD I automatically increased caloric intake and my weight went up. Bodyweight per se does not bother me as much as how my clothes fit and how I look in the mirror. I have been 190 lbs. in the past w/12% BF. I’m 5 lbs. heavier than that but BF% is much higher. If I were 195 lbs. and 12% BF, I would not be complaining but that is not the case.

          2 weeks ago, I experimented with trying to increase SA through heavy cream for a week, a pint per day but could not get past the 2nd day. It was making me ill (nausea, digestive issues). I was aiming for a week just to see how that would affected BW.

          1. Yeah, This is just my opinion, but its pretty easy to shoot past maintenance calories if we start consuming extra saturated fat. My wife makes a banana bread with heavy cream, butter and extra chocolate chips at my request. When I put the recipe in cronometer a slice still had like just under 400 calories whew! I know my metabolism has increased as I dropped weight. I did eat above maintenance the first few weeks and still lost but after that I had to drop just below. Normally on any other way of eating I would have to titrate down to keep loosing, this was not the case with TCD, I stayed at just 10% below maintenance for basically 6 months and kept loosing. I now eat maintenance and I’m still losing a little so my maintenance must be slightly higher now. Just like a Korean starch eating college student lol.

          2. Just for the record and to not confuse. I am still consuming a lot of saturated fat (80+ grams a day). I just kept my total calories just under maintenance.

          3. People keep telling me that I am underfed and the apps like FitPal tell me that my maintenance calories should be 2800. I just cannot eat like that anymore…my days putting Sizzler’s buffet out of business are over! If I need to add 600 calories to hit that target (if undereating IS the issue) I would have to drink those calories which is not good for my gut, either. Bloated!

          4. I’m not suggesting you eat more calories, I was only suggesting you eat below your maintenance level. I was trying to say its easy to exceed our maintenance when adding supper dense fat sources to our diet. As far as what an app tells you is maintenance its just a guess by the app. The only real way to know is to eat a set calorie level every day for a week. Weigh the first day and weigh again the last day. If you gained weight on lets say 2200 daily then your maintenance is likely lower than 2200. if you lost then its likely higher. if its within 1/2 lb. you are very close. Once you find your own maintenance level you can adjust down by 10% and eat at that level for a week and see what happens. Some here may disagree, I just know this has worked for me, and 4 other people I have helped with TCD. I’ve lost 38 in just over 6 months, my best friend 40 in about 5 month, my coworker 13 in roughly a month, another friend 18 in just over 2 months.

          5. I must no be conveying what I am saying properly because you don’t seem to understand what I am saying.

          6. I was talking about maintenance calories. In the beginning you said 2200, but you were exceeding that with TCD. If 2200 is maintenance for you. I’d suggest 2000 and eat TCD way.

  10. Hi Brad-
    Only slightly related question:
    is allulose OK for us Croissant-heads? Also, while I’m at it: PLEASE make capsules for that nasty sterculia oil! I manage by squirting to the back of my throat & chasing with something like kimchi, as I’d previously mentioned, but boyoboy…

  11. Also, btw, my son found Chisen Foods Keto Mayo. Ingredients:
    Refined coconut oil
    Egg yolks
    Rosemary extract.


  12. Hi Brad,
    I wanted to order your Butteroil once again but now in Arizona its HOT.
    Do you think it will leak out in the box?
    Will it ruin it in anyway with it being in our hot temps for a bit on its journey to my house?
    Sorry to have to come on the comment section to ask however I see no way to contact you.
    We have ordered a few times (but in way cooler temps)
    Thank you for helping me out here~

    1. I think it will be fine. The melting point is really quite high indeed. My guess is that in a truck out of the sun it will be OK, but if you order some and it turns out NOT to be OK I’d refund you. I’m interested in your feedback on how this works out.


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