Friday, 5 April 2013

Powdered food ( carbs? ) appears to be very evil

Hat-tip to "steve" for this paper + to sidereal for supplying the full text.

We decided to compare the effects of three different puri-fied diets on body-weight development and physiological parameters in C57BL/6N mice when identical diets were either provided in powder form or as pellets.

Ok for the jist of this paper,  we are simply feeding obesity-prone mice many different diets and seeing what happens to their fat mass. The different diets are......

1) Chow=control diet in 2 varieties, hard pellet form and a form where its ground into a powder
2) "High-fat"  60% fat, 19% prot, 21% carb, both in the hard pellet and powder forms
3) "western style" 36% fat, 17% prot, 47% carb, . in hard pellet form, this was provided in 3 different flavors ( peanut, chocolate, banana ), to test the support for food reward in energy intake, but also it was provided in powdered form.

 To start with, here is the graph of body weight in response to the hard pellet forms of the diets, again, nothing we don't already know, the mice are lean on chow and obese on high-fat and western style.

Now, here comes the first interesting part of the experiment, something of which I certainly have never seen before....

This is the graph of the 3 chow/high-fat/western diets given in powdered form. Yes thats right, once you turn the hard-pellet into powder, the "chow" control diet that usually produces a lean rodent now produces an obese rodent! Infact all 3 diets in powered form produced the exact same degree of obesity. Please note, no changes were made to the "chow" diet other than it was simply ground into a powder. I.E. there was no change in macro-nutrient ratios.

But that aint all, it gets even better, 

I suppose your thinking now that since the "chow-powder" diet induced obesity, the mice must be have been gorging on extra calories? Remember the golden rule of obesity research? All that matters for fat mass balance is CICO.

Well, sorry, but the golden rule just fell flat on its face. Because the mice eating powdered chow ate just 0.4% more calories than the lean mice eating hard pelleted chow. Not statistically significant.

Infact all mice eating all 3 different versions of the powdered diets consumed pretty much the same amount of calories. Normally, mice eating high-fat consume extra calories compared to chow when both are hard-pellet form, but not so for powdered form. In powdered form, mice stop showing hyperphagia on high-fat, although they still develop obesity. There is something gruelingly suspicious here, somehow, changing the texture of the diet changes the diets satiating properties if the diet is high in fat.

This reminds me or something I have noticed when eating butter myself. Namely that, butter that is gently warmed and drank is more satiating than cold butter eaten straight from the fridge.

What about insulin, was insulin raised on the chow-powder diet?


Insulin on all the powder diets was absolutely through the roof. As was leptin. I have no idea if this insulin is due to hyper-secretion or insulin resistance. Despite the very high insulin levels, I would be hesitant to say that this is what is causing the obesity in the powder feed mice, although its not impossible. 

Apparently, there was no difference in body weight in the mice fed the different flavored western style diets, thats bad luck for the food reward hypothesis. 

Here, we show for the first time that a pellet-based high carbohydrate/starch diet fails to trigger obesity, whereas the same diet given in powder form produces an obese phenotype similar to a HF or W diet. While all mice receiving the high-carbohydrate C diets ingested very similar amounts of food and lost similar quantities of energy through faeces, they displayed quite different body-weight gains.

The conclusion from this paper seems to be that, powdered carbs in particular are obesogenic. Its not correct to say this of the high-fat diets because the high-fat and western diets induced similar weight gain regardless if they were hard-pellet or powder.

The thing that immediately comes to mind here is flour and flour/bakery products. This is powdered carbs that we feed to humans. I think we all know how obesogenic these foods are, for example, doughnuts, cookies, cakes, pastry, pizza bases etc. If this research paper is anything to go by the lesson here should be that we should all stay away from powdered carbs.  If your on the LC bandwagon and want to cheat, I would suggest that cheating with powdered carbs is the absolute WORST thing you can do. 

Though generally any source of carbs will make you gain weight when straying from the LC bandwagon, I would say DEFINITELY stay away from powdered carbs. Refined sugar is also quite close to the "powdered carbs" category. Extrapolating to say that "all powdered" food should be avoided however, is, not so straight forward. 

For example, Whey protein is obviously a powdered food, yet it is anything but obesogenic.  And infact is more associated with weight loss and leanness. 

There is some speculation from the researchers as to why the hard-pellet forms dont induce weight gain, including the hard-pellet form passing through the GI tract undigested and turning to SCFA in the colon, aswell as the hard-pellet form increasing postprandial thermogenesis.  

The researchers close with the thought that, all obesity research that has been done comparing high-carb chow to high-fat is essentially flawed. 

Finally, we would like to critically ask whether a pellet- based, high carbohydrate/starch diet is a proper C diet when used for comparison with HF diets. Feeding diets with . 45 % energy as fat is meanwhile accepted as a ‘gold standard’ to induce obesity in normal or transgenic mice models. The pellets of this C diet have an exceptionally hard texture and are therefore difficult to chew, to swallow and may need huge amounts of energy for handling in the gastrointestinal tract. They may also cause a loss of energy by the delivery of larger amounts of undigested starch to the microbiota and may after all produce an artificially ‘lean phenotype’.

Obesity research being flawed? Imagine that.........


  1. Wow! That's a striking result. So now all obesity research using rats has got to be re-done using powder as well!

  2. Magnificient!

    I hope there will be a follow-up with wistar rats though.. I like them better than black 6 mice..

  3. I think this study:
    Was used by you-know-who to support food reward.

    Here is another, similar one:

    I wonder if it isn't less about reward and more about more sugar(/fat/everything) hitting the bloodstream earlier -> high sugar spike -> high insulin spike (affecting beta cell growth?).. and, if reactive hypoglycaemia would exist (the good doctor told me it doesn't!) higher probability of it happening.. hm..

    I have had this suspicion for some time now, that flour and sugar are more obesogenic than other carb sources..

    1. I didnt see any explanation for the obesogenic affect of the powder diet by the researchers in this paper. Everything is speculation at this point, but to me it seems like initial signals from the GI tract are "sufficient" to start the obesity snowball.

      It *HAS* to be something to do with carbs because whey is a fast digesting powdered food that doesnt induce obesity.

      The other surprising finding is that powdered high-fat diets reduced the calorie intake the mice consumed suggesting increased satiety. Easily digestible fat is therefore more satiating. I think this makes sense because fat actually has to be hydrolyzed from triglycerides into free fatty acids before they can suppress ghrelin/increase incretins etc.

      My guess is that the pellet-form of the high-fat is reducing the speed that the triglycerides are broken down so the mice eat more due to a higher energy density of fat. I think this explains why liquid warm butter is slightly more satiating than cold-hard butter. maybe..... :)

  4. irony, thy name is ... OBESITY RESEARCH. ;-)

    hope you're feeling better, Kindke!

  5. Kindke is BACK.

  6. Excellent post, Kindke.

    I should transfer your hat tip to Ian Spreadbury, who pointed me to the paper. He has some suspicions that could provide part of an explanation. To quote: " may be important that the Western diet resembles a bacterial growth medium."

  7. Hi Kindke,
    Nice post, thanks. I think the food texture per se might have had something to do with this. For mice fed normal pelleted low fat diet, every meal is like a mini-exercise session – they have to climb up and gnaw the hard pellet out of the hopper for every morsel. 24 hour energy expenditure data has shown this in the past, eg, PMID: 15561960. The opposite is true for any diet in meal (powder) form. There are definitely a LOT of problems with obesity research :/ even in mice.
    all best,

  8. @Bill: Good points, but do note that the pelleted control chow (CHO) had quite a different impact than the pelleted high-fat or western chows. Yet, the paper does indicate that the pellets of the control chow were harder in texture than the pellets of the other two pelleted chows.

  9. Wow, why have I mist that blog entry. That's probably imho a game changing paper. This would also explain the Kitavan and other tater. There's also another aspect of starches that got lost in the last years of blogo-chatter. The difference between amylose and amylo-pectine in natural form and what happens when ground.

  10. We should not forget that potatoes can be eaten in their normal form but that it is also used in powedered form for instant mashed potatoes and other products (dumplings).

  11. That's interesting. The silly glycemic index stuff suggests that fat should slow down absorption of carbs--but if we're talking hard little pellets, and the fat softens them up--that sure throws a wrench into the whole mess. Is there really any such thing as a "hard" pellet that's 60 percent fat?

  12. @Donny, yes. I made a 60% fat diet based on cocoa butter and it was so hard the mice could barely maintain body weight on it. At first, we were excited that it might be a unique effect of cocoa butter (compared to lard), but food intake measurements proved otherwise.

  13. Bill--oh yeah, hardened fat. Guess that puts a new spin on studies showing decreased body weight when mice are kept at a lower temperature--I wonder, do they control for the temperature of the chow, effects that has on soft/hardness of the pellets?

    Still, once the food is actually inside the mouse, getting warmed up, even a solid fat like cocoa will soften up considerable.Fat might slow digestion of the carbs--but if it facilitated break up of the pellets into smaller particles more quickly, maybe there'd be an effect? I'm probably trying too hard here, I realize, there's no reason for powdered chow to make mice fatter by the same mechanisms that high-fat pelleted chow does at all.

  14. Really interesting.

    Obesity research, flawed? well at least he didn't go all out and call it a house of cards...

  15. I wonder if the issue is that in rodents at least, that whole foods are poorly absorbed whereas food pulverized to a powder is absorbed and better able to spike insulin and facilitate fat storage.

    It may be not that rats gain fat on high fat diets, but rats poorly digest carbohydrate for energy whereas fat is entirely absorbed.

    Whenever there is a weight difference for the texture of food I would assume absorption ist he reason. E.g.swallowing almonds (no calories) vs chewing them vs grinding them to a peanut butter like paste, all yeild different amount of energy to body.

    1. "I wonder if the issue is that in rodents at least, that whole foods are poorly absorbed whereas food pulverized to a powder is absorbed and better able to spike insulin and facilitate fat storage."

      Thats what the researchers and myself think is happening. Powdered food is easier to digest. This is a tough challenge for the CICO argument, because now you have to explain why consuming equal calorie amounts produces wildly different body compositions. The other point about this study is that mice on high-fat consumed *less* calories in powdered form but still achieved similar degree of obesity compared to hard-pellet high fat.

      "swallowing almonds (no calories) vs chewing them vs grinding them to a peanut butter like paste, all yeild different amount of energy to body."

      question is, how satiating would it be to swallow whole almonds compared to chewing them a bit? I need to perform this experiment myself!

  16. Excellent find, Kindke! I'm about to submit an NIH grant proposal to study effects of refined food chow on cognition in rats, and this will be a useful reference to include, as grist for the mill if you'll allow me that simile. I especially like how it fits in with the acellular carbohydrate hypothesis and how refining foods changes the way the nutrients enter the system, and in turn, how this changes the signaling profile of the food consumed.

  17. Not having access to the full text, one question about the feeding protocol. Was the powder fed dry, or was it moistened?

  18. This study reminds me of some of the research cited by Seth Roberts in 'The Shangri-La Diet'. Dr. Israel Ramirez found that rats got fatter if water was added to their chow. "Young rats given wet food gained more weight than rats given dry food, even though both groups had water available from a water bottle. The effect was huge:The right amount of water could double the rats' weight gain." (From page 153 in the Roberts book)