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Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

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July 17, 2017

Dear Mark: Low-Fat Beats “High-Fat”; Prunes for Bone Health

By Mark Sisson
27 Comments

Low Fat StampsFor today’s edition of Dear Mark I’m answering a pair of great questions. First, Vaughn asks me about a recent study where ethnic Chinese participants were placed on several different diets, and those on the “low-carb, high-fat” one actually did worse than those on higher carbs and lower fat. Should you give up your low-carb approach? Then, I explore the bone-strengthening effects of prunes and discuss the Simon and Garfunkel diet.

Let’s go:

Hi Mark,

What are your thoughts on this study from China where a low-fat diet beat out a high-fat diet in healhy adults? http://www.sciencedirect.com/science/article/pii/S2352396417302529#t0010

Vaughn

Interesting paper. Thanks for the tip.

It sounds damning.

Chinese adults were split into three groups, each receiving different diets. One group ate high-carb, low-fat. One ate moderate carb, moderate fat. One ate high-fat, low-carb. Protein was the same across all three groups.

After six months on their respective diets, the high-carb group had the best metabolic outcomes. They lost the most weight, the most inches off their waists, and saw the biggest improvements to their blood markers. The next best was the moderate carb/fat diet. The worst was the high-fat/low-carb diet.

Oh man, Sisson. You mean to tell me that the LCHF group subjects were eating more fat and had the worst results. That’s that. I’m out. This is all a sham.

Hold on a minute. Something in the study design caught my eye.

By replacing a proportion of energy derived from carbohydrates (white rice and wheat flour, the most consumed carbohydrate sources in China contributing to 70% and 17% total carbohydrate respectively) with fats (soybean oil, the most consumed edible oil in China rich in unsaturated fatty acids), we achieved the required distribution of fats and carbohydrates in the three diet groups, which represented macronutrient transition in the past 30 years in China.

They replaced carbs with pure soybean oil. That’s how they modified the macros—taking a little flour away and pouring an isocaloric glug of soybean oil all over everything. Anyone else feeling nauseated?

As stated, however, this intervention does reflect the dietary trends in China. It also reflects the trends in the standard American diet. Americans (and everyone else the world over) are eating far more soybean oil than ever before. From 1909 to 1999, American consumption of soybean oil rose more than 1000-fold. Yes: Those are three zeros.

But it’s not relevant to most of my readers.

Something else jumped out at me. High-fat and low-carb were actually higher-fat and lower—carb. That’s an important distinction. Relative to the other diets, folks in the third group were eat fewer carbs and more fat. Relative to the Primal eating plan, they weren’t. At 40% fat, 46% carb, they weren’t low-carb or high-fat in an absolute sense.

Forty-six percent carb isn’t low-carb by any stretch of the imagination. The results from this study probably don’t apply to someone eating 20% carbs.

All that said, I find it plausible that ethnic Chinese would have genetic adaptations to a higher carb diet. They tend to produce high levels of salivary amylase—an oral version of the digestive enzyme responsible for digesting starch—which is an indication of ancestral exposure to starch. People who make more salivary amylase have better metabolic responses to starch intake. In the context of higher-carb diets, they’re also less likely to be obese.

Maybe not, though. A 2015 paper found positive relationships between starchy carb consumption and metabolic syndrome prevalence among Chinese adults. Carbs from other sources—fruits and veggies—had no such relationshp to metabolic syndrome.

Confusing stuff, eh? There’s always some new wrinkle to explore.

JTB asked:

Mark, if you do a follow up piece, consider looking into the studies on dried plums, and perhaps also the study on the “Scarborough Fair” diet, which also showed positive bone-health results for the group using a specific set of herbs, fruits and vegetables.

You’ve got it, JTB. Everyone overlooks prunes, and I’m a big Simon and Garfunkel fan. I accept your proposal.

What’s the deal with prunes? Most people only think of them as tools to fight constipation. And, boy, do they. Prunes work so well that prune juice has become a joke. C’mon, what’s the first thing you thought of after reading the word “prunes”? Exactly.

Prunes are great for the gut, but they don’t just instigate excellent defecation. They actually promote good gut health by increasing the growth of beneficial microbes and inhibiting the growth of pathogenic microbes. They may help prevent colon cancer by acting as a prebiotic.

Animal and cell culture studies do indicate benefits to bone turnover. There are different theories as to why. Prune polyphenols are nice but probably not responsible for the effects on bone health. My guess is it’s the prebiotic effect, given that we know from last week’s post that probiotics can improve bone health.

If these effects hold in humans, and I think they will, prunes are an excellent choice. They don’t even spike blood glucose all that much, despite being dried fruit quite high in carbs. 

Now let’s look at the Scarborough Fair Diet. First, open this in a new tab and turn the volume up.

The Scarborough Fair Diet’s quite interesting. Researchers constructed it from all the fruits, vegetables, and herbs that have been shown in animal studies to improve bone health. Most were extremely high in phytochemicals. This diet was pitted against a diet containing basic fruits, vegetables and herbs. Both diets had the same amount of plant foods.

Where the Scarborough Fair Diet had parsley, sage, rosemary, thyme, and garlic, the regular diet had mint, basil, and oregano.

The SFD had prunes and oranges; the regular diet had apples and bananas.

The SFD gave bok choy, rocket, red cabbage, and lettuce; the regular diet gave spinach, silver beet, and white cabbage.

The SFD gave broccoli, onions, tomatoes, mushrooms, green beans, cucumbers, and leeks. The regular diet gave carrot, pumpkin, courgette, peas, and cauliflower.

Both contained very nutritious foods. I’m a big fan of most of them. But only the SFD improved bone turnover markers and calcium retention in postmenopausal women. That’s a very cool effect, and it suggests that the various nutrition-based bone health interventions in animal studies likely carry over into humans, too.

That’s it for me, everyone. Thanks for the great questions. Be sure to help out with your input down below or throw a few more questions my way. Always happy to help.

Take care!

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27 Comments on "Dear Mark: Low-Fat Beats “High-Fat”; Prunes for Bone Health"

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His Dudeness
His Dudeness
2 months 3 days ago

I’ve always wondered why every official “low carb vs. low fat” study combines a minuscule change in the macronutrient ratio with some sort of industrial frankenfat. Replace the simple carbs with grass-fed tallow or pastured lard, and drop the carbs to under 20g/day and see what the results are.

Paleon Bon Rurgundy
Paleon Bon Rurgundy
2 months 3 days ago

A LCHF Bridge over Frankenfat Troubled Water

Shary
Shary
2 months 3 days ago

If by industrial frankenfat you are referring to soybean oil, it’s icky stuff and can be found in many processed foods these days, probably because it’s cheap. It has an overpowering, off-putting flavor that, IMO, gives food a slightly rancid taste. It’s the primary reason why I switched from commercial mayonnaise to making my own. Fortunately, the market hasn’t been cornered. There are now a few brands of mayo available that do not use soybean oil, such as Whole Foods 365 brand and Mark’s own Primal mayo.

HotDaddyOh
HotDaddyOh
2 months 3 days ago

As somebody who just bought 5 gallons of grass fed beef tallow, I approve of this message!

Mark, slightly off topic but could you post the title of the studies you link, at the bottom of your post or something? Inevitably somebody will bring this up to me in 9 months as a reason my diet will kill me, and it would be much easier to search for this article (and all your other wonderful reviews of studies) if the exact name was here somewhere!

Victoria Barnett
2 months 3 days ago

Isn’t there some evidence that the boron levels in prunes might be contributing to bone health?

Mathieu
Mathieu
2 months 3 days ago

Sure the Low Carb diet was poor (and not that low), but the High-Carb / Low Fat diet had poor quality carbs and still did good. Food for thoughts.
By the way, carbs don’t make you obese. Constant overeating does (be it high carbs or high fat).

b2curious
b2curious
2 months 3 days ago
So far as I know, nobody here is saying that eating too much, be it carbs or fat, doesn’t make you gain weight. However, a diet high in decent fats (NOT seed oils), low in carbs, and moderate in protein, tends to naturally decrease caloric intake without counting calories and measuring everything. Partially because fats take longer to digest, thus making one feel full longer. Additionally, a diet high in carbs tends to make one reliant on glycogen (glucose) for energy, and poor at burning fat for energy. Since you can only store a finite amount of glycogen at any… Read more »
Mathieu
Mathieu
2 months 2 days ago

This:
” In the context of higher-carb diets, they’re also less likely to be obese.”
Kind of insinuated that high carb diets make ou obese 😉

b2curious
b2curious
2 months 2 days ago
That’s because most people, on a high carb diet, will end up obese. There are exceptions, which I will get to later. For most people, my comments above do a decent job of explaining the basics of why a high carb diet is not the best for weight control. Also add in the fact that different foods affect people’s metabolisms, hormones, and what not, differently. I saw a study a while back where people were randomly assigned to two groups. Both increased their daily caloric intake by the same amount for a set period, I think it was a couple… Read more »
Mathieu
Mathieu
2 months 2 days ago

I talk about carbs, you talk about candies…
High carb diet (ideally good carbs), as long as you are not overfeeding, will not get you fat.
Body composition or whatever is not the subject, it is just the shortcut “high carb => obese” that is wrong.

b2curious
b2curious
1 month 30 days ago
While that is an extreme example, it does illustrate that, at least in some cases, the types of calories matter, that it’s not just a simple matter of controlling caloric intake. Also, the statement you initially referenced does imply that eating a high carb diet makes people obese, but not everyone – you know “less likely.” As I said, many people are obese on a high carb diet and that is partially because a high carb diet makes it harder to keep your caloric intake down. You may want to peruse some of the success stories, in this site. I… Read more »
Ross
Ross
2 months 3 days ago

Yeah, 46% carbs is high, and not a carb-controlled diet by any stretch.

If I’m on 2,000 calories per day, and 46% of my intake is carbs, that’s 920 calories from carbs. There are approx. four calories in a carb so we have 920 / 4 = 230 carbs.

Combine that with 88 grams of fat (2000 * .4 / 9) and you have the classic gotcha of sugar + fat = trouble.

Mathieu
Mathieu
2 months 2 days ago

Just avoid carb rich / fat rich meals and you’re good 😉

Faith
Faith
2 months 3 days ago

Prunes – meh…. I can handle dried pluots, but not really prunes, for whatever reason.

BUT… plums are one of my favorite fruits – I wonder if they are just as good?

Petra
2 months 3 days ago

“They tend to produce high levels of salivary amylase—an oral version of the digestive enzyme responsible for digesting starch”
While living in China, I never got why the spitting thing is so extravagant here. Knowing this,it gives a whole new meaning.

Jas Walia
2 months 3 days ago

Such a nice post. Thanks for sharing this nice information.

PaleoBunny
PaleoBunny
2 months 3 days ago
I’m Chinese and more and more of my Chinese friends and family are starting to lower their carb intake with the uptick of obesity and diabetes in Asia and in their own families; I think it’s a misconception that Chinese people eat tons of carbs; the more health-conscious ones may only eat 1/4 cup of cooked rice with a meal full of vegetables and protein. Some like myself just don’t eat much rice anymore, and very little wheat-based food, which is foreign to China anyway (white flour was not a normal ingredient and for a long time was expensive). For… Read more »
Paul Richard
2 months 2 days ago

Really, helpful blogging. Thanks for sharing!

Katie
2 months 2 days ago

Mark, I love how you do the detective work for us on these controversial studies. Your blog is such a fantastic wealth of information. Thank you!

Wepullup
2 months 2 days ago

Would love to see a similar study but replacing the flour with more natural sources of fat (coconut oil, lard, etc.)

Jack
Jack
2 months 2 days ago

Here is a very interesting article about a study comparing soybean oil and coconut oil. I think there wre limks to the study in the article.

https://www.eurekalert.org/pub_releases/2015-07/uoc–soc072015.php

Zoltan
Zoltan
2 months 1 day ago
Prunes have actually been PROVEN to improve bone mineral density (BMD) in humans (postmenopausal women to be exact). The researchers gave 100 grams (3.6oz) of prunes to half of the participants and dried apples to the other half. Both groups received the same amount of supplemental calcium (500mg) and Vitamin D (400IU). Prines “significantly increased BMD of ulna and spine in comparison with dried apple. In comparison with corresponding baseline values, only dried plum significantly decreased serum levels of bone turnover markers including bone-specific alkaline phosphatase and tartrate-resistant acid phosphatase-5b. The findings of the present study confirmed the ability of… Read more »
Lance
Lance
2 months 1 day ago

It appears that JBT is asking about dried plums, and Mark is answering with a discussion on dried prunes. Is this just a typo?

CooP
CooP
2 months 1 day ago

A dried plum is known as a prune – they are the same thing

Larry B.
Larry B.
2 months 1 day ago

The dried plums at my supermarket and preserved with potassium sorbate – do the health benefits outweigh the any negative effects from this preservative?

Zoltan
Zoltan
2 months 2 hours ago

If prunes are the only food in your diet preserved with potassium sorbate, you’re almost certainly safe. If you consumed a lot of preservative-laden food, your intake *might* become too high, but this is unlikely on a Primal diet.

Jony
17 days 6 hours ago

I agree with the Zoltan.
You may follow him for a month for this. If you found it good then apply it in your daily life or then you can leave it too.

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