When readers first linked to the “paleo diet makes you fat!” study in comments, I replied that I generally dismiss mouse and rat studies as irrelevant to humans, except in certain circumstances. I should probably talk about those circumstances.
But first, I’ll explain which studies I dismiss outright: pretty much all diet studies that involve rodents. We’re not rodents. The foods that have negative effects on rodents may have positive effects on humans and vice versa.
The big cholesterol scare started more than 100 years ago when scientists fed cholesterol to rabbits, who rapidly developed heart disease as a result. Oh my gosh, cholesterol must cause heart disease in humans!
Stupid conclusion. Rabbits are herbivores. They don’t eat cholesterol. There’s no reason they should have the biological machinery to deal with cholesterol. So – duh! – it builds up in their systems and causes problems. I’m pretty sure if we fed lions an all-vegetarian rabbit diet, they’d become quite ill. But that doesn’t mean carrots are bad for rabbits or humans. It simply means lions are obligate carnivores.
So even if researchers fed rats and mice a true paleo diet of meats and vegetables, I still wouldn’t give a rat’s ass (pardon the pun) about the results — positive or negative – because there’s simply no reason to assume those results translate to humans. We’re not rats. The diet that’s perfect for them is very unlike the diet that’s perfect for us. The researchers in the dumbass “paleo diet makes you fat!” study mentioned that standard rat chow is 3% fat. Has there ever been a group of paleo humans who lived on a 3% fat diet? I sincerely doubt it. Rats are probably biologically geared to thrive on an extremely low-fat diet. We’re not.
But of course, researchers in these studies rarely feed mice and rats anything like the human diet they’re supposedly testing. The “paleo” diet in the dumbass study consisted largely of isolated casein, sugar and canola oil. It was nothing like a paleo diet. The study has absolutely zero relevance to humans eating an actual paleo diet.
This little sleight-of-hand seems to be a habit among some researchers. More than once, I’ve dug into a mouse or rat study of the “Atkins” (ahem-ahem) diet and found that the primary fats were Crisco or corn oil, and the sole source of protein was casein … you know, just like Dr. Atkins recommended. Then when the rats or mice became fat or sick, dingbats in the media dutifully reported that New Study Show Atkins Diet Causes (insert scary result here)!!
Utter nonsense.
So when should we pay attention to rodent studies? Well, I’ll least give them a look if they test the result of drugs or hormones. In the animal kingdom, hormones are the chemical messengers that trigger the code written into our biological software. Hormones have been around since before humans existed. I think we can safely assume hormones produce similar effects in a man and a mouse.
So if researchers pump male mice full of testosterone and those mice become leaner, stronger, and start throwing punches in bars at the slightest provocation, I’d expect to see similar effects in male humans. If researchers inject rats with high doses of insulin and the rats start eating like crazy and getting fat, I’d expect a similar result in humans. But I’d still take those studies with a grain of salt.
Here’s the type of rodent study I don’t take with a grain of salt: those that disprove a supposed Immutable Law of The Universe. Back in 2011, I wrote about a study in which researchers calculated how much food mice were eating ad libitum. Then they took one group of mice and cut their daily calories by just 5%. Here are some quotes from my post:
Now, according to Jillian Michaels and the other leading experts in thermodynamics, there are only a couple of possible outcomes for these experiments:
- The calorie-restricted mice, who were prevented from making little pig-mice of themselves, ended up weighing less and were leaner.
- If the calorie-restricted mice somehow ended up fatter, it could only be because they were far less active than the mice who ate freely.
Yup … if you get fat, by gosh, it means you’re either eating more or moving less. Now let’s look at the actual results:
At the end of the second experiment (three weeks), the average weight for both groups was virtually identical — it was also virtually identical to their baseline weights. But the calorie-restricted mice had 43.6% more fat mass and 6.4% less lean mass than the free-eating control mice.
Ah, well then, the mice who gained fat mass must’ve been less active, right?
Nope. According to the study data, there was no difference in locomotor activity levels between the two groups.
The calorie-restricted mice ate less, they moved around just as much, but they ended up weighing the same as the mice allowed to eat freely, and also ended up with more fat and less muscle. Oh, dear me … did these mice find a way to violate the laws of thermodynamics?
I paid attention to that study because the calorie freaks insist that according to the laws of physics, if you eat less and move around just as much YOU MUST BURN FAT FOR FUEL AND LOSE WEIGHT. IT’S AN IMMUTABLE LAW OF THE UNIVERSE. But these mice ate less, moved around just as much, and gained fat mass while losing muscle.
Yeah, it’s just a mouse study, but the laws of physics are the laws of physics, period. They don’t apply to humans and then go on vacation when mice saunter into the room. So if the laws of physics say eating less while remaining active must always lead to fat loss, that would apply to both large and small furry creatures.
No, those mice didn’t violate the laws of physics. And no, the experiment didn’t disprove any laws of physics. But it did disprove the calorie-freak argument that cutting calories while remaining just as active MUST ALWAYS LEAD TO BURNING AWAY BODY FAT BECAUSE THE LAWS OF PHYSICS SAY SO.
The laws of physics say no such thing. They merely say that if you lose weight, you burned more calories than you consumed. These mice – despite remaining just as active – slowed down their metabolisms and burned muscle tissue for fuel in order to get fatter. It was probably a programmed reaction to what their little mouse bodies interpreted as a risk of starvation. No laws of physics were harmed in the process.
So here’s the one part of the “paleo diet makes you fat!” study I found relevant:
After 3 weeks, mice fed the LCHFD began to diverge from the chow-fed group, and at 5 weeks the difference in body weight was statistically significant. At the end of the study, white adipose tissue mass was also significantly increased. The LCHFD has a higher energy density than the chow diet (24 vs 13.5 MJ kg−1); however, the increased body weight of mice fed the LCHFD was not associated with a higher energy intake.
Yup, the mice fed the full-of-crap “paleo” diet (which tripled their sugar intake) gained more weight and more body fat. We can’t blame it on palatability, because they didn’t say, “Oooh, this is yummy!” and eat more. We can’t blame it on consuming too many calories, because they didn’t consume more calories. So if the researchers kept accurate records on food consumption (and it appears they did), we have a situation where mice eating a crap diet got fatter than their control-group cousins, despite not eating more.
That’s a relevant result, even though it’s a mouse study. It disproves the dearly-held belief among the calorie freaks that getting fatter is always and forever the result of eating too many calories BECAUSE THE LAWS OF PHYSICS SAY SO. And it lends credence to the belief that food quality affects how calories are partitioned, burned and stored. Different foods send different commands to the biological software. That’s the only useful lesson from an otherwise garbage study.
And once again, no laws of physics were harmed in the process.
Of mice and men. Again.
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As far as I know studies conducted on mice are not enough to prove usefulness and safety of a new drug. Such studies are not conclusive enough even for stage 1 of drug development process. Why than rodent studies are used to make conclusions of healthiness of a human diet?
No, of course we wouldn’t approve a drug for humans based on a mouse trial. But with a drug (assuming the mouse equivalent of a human dose), I’m willing to accept that the effects are likely to be similar.
As far as I know studies conducted on mice are not enough to prove usefulness and safety of a new drug. Such studies are not conclusive enough even for stage 1 of drug development process. Why than rodent studies are used to make conclusions of healthiness of a human diet?
No, of course we wouldn’t approve a drug for humans based on a mouse trial. But with a drug (assuming the mouse equivalent of a human dose), I’m willing to accept that the effects are likely to be similar.
I understand what you are saying Tom. Imagine if they used the same logic for chocolate and ibuprofen? This two common items are harmful to cats and dogs and yet there is no headlines screaming for these to be banned. What argument would they use? They are not humans, they are cats and dogs. Humans can digest these with no harm caused.
Well, that’s not the conclusion one of the authors, Associate Professor Andrikopoulos, took away from this study:
“The moral of the story is that calories matter. If you eat more calories, you will put on more weight.”
https://pursuit.unimelb.edu.au/articles/paleo-diets-weight-gain
You are not claiming that he is misrepresenting the outcome of his own study, are you?
Goodness, no. A guy who feeds sugar, canola oil and casein to mice and then declares that the results apply humans on a paleo diet could never be accused of misrepresenting his own study.
I always have a good laugh when I read ‘, you burned more calories …’.
You cannot burn a calorie. Period. (did someone mention laws of physics? )
The (obsolete) concept of calories refers to the amount of energy released during a combustion (or a reaction), and a calorie represents the amount of energy required to heat one liter of water from 14°c to 15°c (for our friends across the pond that is 1.056 quart of water from 57.2F to 59°F)
Calories and BTU are scientifically obsolete. Nowadays the official unit is the Joule. (easier to work with other SI units).
My mind boggles. How come so-called scientists use such obsolete concepts? As Dr Lustig said, isocaloric (or should we say isojoulic) is not isometabolic.
I like to illustrate that concept by explaining that one litre of gasoline is chock full of calories. I wonder however how the human metabolism will ‘burn these calories’…
Have a good weekend y’all
E.
Calories, Joules, and BTU are all units for measuring energy. Calories even have a pretty handy definition using SI units. One is readily convertible to the other. Use the one that suits your purpose.
Yes it’s a bit off to speak of burning calories, but it’s a well understood phrase. Making people say you oxidized more food with a potential energy of X calories instead of saying you burned X calories doesn’t really help communicate the point any better.
I use a metaphore to convey the idea that “calories” (or joule) is not a very interesting dimension for food.
The first one is to say that comparing the quality of a food by its calorie content is like assessing the quality of a closet at the amount of heat it produced when burning it down.
The biggest issue I take with the ‘laws of physics’ and ‘laws of thermodynamics’ zealots is that they generally don’t understand the scientific use of a bomb calorimeter. That is: a closed system–which a human body is not. We *could* argue there’s only a single point of intake. But between the obvious waste management systems we use so effectively, thermogenics, perspiration, and even respiration, no one can tell me they can quantify their sweat output, CO2 output in each exhale… I mean, it’s nuts.
But there are enough anecdotal “I ate 500 calories less than I did before and lost x pounds” that I feel as though we’ll never hear the end of it. It’s similar to the fact that Forks over Knives has been debunked, but you still see it used for the vegan/vegetarian agenda, since, you know, they feel so much better cutting out meat (and twinkies and other crap that clearly had nothing to do with it).
Keep fighting the good fight, Tom. If not for sanity sake, at least for our amusement 🙂
People aren’t immune to the laws of thermodynamics, it’s just that there is a great deal more to applying them, than is assumed.
Or when you throw in a bit of marketing….
For example, another ‘obsolete’ unit, that is still revered around the world:
…the Horse Power (hp or bhp)…
originally created as a marketing gimmick so that in the early days of steam engines customers could compare the *work* the stema machine did in relation to a unit they knew.
Why did I highlight ‘work’? Well car’s ‘power’ is still marketed in ‘hp’…. but it’s not power, it’s ‘work’.
The real ‘power ‘ of a car is its torque, ie the rotation force applied to the weels to make it accelerate. But I guess newton/meters is not too sexy in the marketing department…
😉
I understand what you are saying Tom. Imagine if they used the same logic for chocolate and ibuprofen? This two common items are harmful to cats and dogs and yet there is no headlines screaming for these to be banned. What argument would they use? They are not humans, they are cats and dogs. Humans can digest these with no harm caused.
I thought the calorie restricted mice did move less in that study (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2880162/).
“TEE (Kcal/day, P < 0.05) and resting energy expenditure (REE, Kcal/day, P < 0.05) were significantly decreased in CR mice compared with AL mice over 3 weeks. TEE was 5.0% lower (7.97 ± 0.14 vs. 8.38 ± 0.46 kcal/day) and REE was 20.7% lower (4.83 ± 0.54 vs. 6.09 ± 0.43 kcal/day) in CR mice than AL mice after 3 weeks (Fig. 3)."
Are you looking at a different study or am I reading something wrong?
You’re missing this part: Locomotor activity or BAT thermogenic capacity did not appear to contribute to the decrease in energy expenditure.
So they didn’t move less. Their bodies found a way to burn fewer calories at rest. In other words, slower metabolism.
Yes I hate the laws-of-physics “experts” as well. I often want to give some of my knuckle-energy to their faces and see if it converts to extra mass because E=mc^2 said so.
If they say something crazy like “running a mile and walking a mile burns the same number of calories” and then I say “Hmm I’m not really sure if that’s how it works,” that’s the point when they go crazy and just start insulting my lack of physics knowledge.
As a result of many conversations like that, I have developed my own way of dealing with idiots: I just run from them as fast as my puny legs can carry me.
Someone once posted replies from actual physicists about calories. Every one of them said that the laws of thermodynamics can describe the process of weight gain, but tell us nothing about the cause.
If you lift a weight and put it back where you found it, you did zero net work, and yet your muscles are tired. Clearly there is more to it.
I always have a good laugh when I read ‘, you burned more calories …’.
You cannot burn a calorie. Period. (did someone mention laws of physics? )
The (obsolete) concept of calories refers to the amount of energy released during a combustion (or a reaction), and a calorie represents the amount of energy required to heat one liter of water from 14°c to 15°c (for our friends across the pond that is 1.056 quart of water from 57.2F to 59°F)
Calories and BTU are scientifically obsolete. Nowadays the official unit is the Joule. (easier to work with other SI units).
My mind boggles. How come so-called scientists use such obsolete concepts? As Dr Lustig said, isocaloric (or should we say isojoulic) is not isometabolic.
I like to illustrate that concept by explaining that one litre of gasoline is chock full of calories. I wonder however how the human metabolism will ‘burn these calories’…
Have a good weekend y’all
E.
Calories, Joules, and BTU are all units for measuring energy. Calories even have a pretty handy definition using SI units. One is readily convertible to the other. Use the one that suits your purpose.
Yes it’s a bit off to speak of burning calories, but it’s a well understood phrase. Making people say you oxidized more food with a potential energy of X calories instead of saying you burned X calories doesn’t really help communicate the point any better.
I use a metaphore to convey the idea that “calories” (or joule) is not a very interesting dimension for food.
The first one is to say that comparing the quality of a food by its calorie content is like assessing the quality of a closet at the amount of heat it produced when burning it down.
A friend of mine went zero carb yesterday. He had been low carb before and I don’t know why he went so low. After 12 hours he was talking about how much he hated it. Some dope commented to him that it is an unhealthy diet and that your body will start to eat its own muscle mass in order to feed that brain. SMH.
Completely agree!
I was in an aquarium once where the marine biologists had rescued a giant turtle from another zoo as it was dying with peeling skin – apparently there were two similar looking sub-species with completely different diet needs.
The new centre realised this and started feeding – correctly – she got better!
@TreatMeGently
The biggest issue I take with the ‘laws of physics’ and ‘laws of thermodynamics’ zealots is that they generally don’t understand the scientific use of a bomb calorimeter. That is: a closed system–which a human body is not. We *could* argue there’s only a single point of intake. But between the obvious waste management systems we use so effectively, thermogenics, perspiration, and even respiration, no one can tell me they can quantify their sweat output, CO2 output in each exhale… I mean, it’s nuts.
But there are enough anecdotal “I ate 500 calories less than I did before and lost x pounds” that I feel as though we’ll never hear the end of it. It’s similar to the fact that Forks over Knives has been debunked, but you still see it used for the vegan/vegetarian agenda, since, you know, they feel so much better cutting out meat (and twinkies and other crap that clearly had nothing to do with it).
Keep fighting the good fight, Tom. If not for sanity sake, at least for our amusement 🙂
People aren’t immune to the laws of thermodynamics, it’s just that there is a great deal more to applying them, than is assumed.
Or when you throw in a bit of marketing….
For example, another ‘obsolete’ unit, that is still revered around the world:
…the Horse Power (hp or bhp)…
originally created as a marketing gimmick so that in the early days of steam engines customers could compare the *work* the stema machine did in relation to a unit they knew.
Why did I highlight ‘work’? Well car’s ‘power’ is still marketed in ‘hp’…. but it’s not power, it’s ‘work’.
The real ‘power ‘ of a car is its torque, ie the rotation force applied to the weels to make it accelerate. But I guess newton/meters is not too sexy in the marketing department…
😉
Work, torque, and power are all distinct units.
Watt defined horse power in terms of whether a steam engine could do work as rapidly as a horse. Power describes the rate at which work is done, or work / time. That is what a car’s horse power number describes. So yes, a car’s power, is indeed power. We usually measure it in horse power, but some countries use Watts.
Sometimes it is true that torque is a more useful measurement of an engine’s ability than power, but torque isn’t power, torque is torque.
In MKS SI units, power is expressed in Newton meters / second (Watts), and torque is measured Newton meters.
In MKS SI units, work is expressed in Newton meters (Joules). Which has the same dimensional units as torque, but it isn’t torque. It can also be expressed in dynes, calories, and British thermal units if you like.
Hi Tom,
“The moral of the story is that calories matter. If you eat more calories, you will put on more weight”
Guess who says that. (via)
From the text of the study: “the increased body weight of mice fed the LCHFD was not associated with a higher energy intake“.
Heh-heh-heh … no surprise there.
I thought the calorie restricted mice did move less in that study (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2880162/).
“TEE (Kcal/day, P < 0.05) and resting energy expenditure (REE, Kcal/day, P < 0.05) were significantly decreased in CR mice compared with AL mice over 3 weeks. TEE was 5.0% lower (7.97 ± 0.14 vs. 8.38 ± 0.46 kcal/day) and REE was 20.7% lower (4.83 ± 0.54 vs. 6.09 ± 0.43 kcal/day) in CR mice than AL mice after 3 weeks (Fig. 3)."
Are you looking at a different study or am I reading something wrong?
You’re missing this part: Locomotor activity or BAT thermogenic capacity did not appear to contribute to the decrease in energy expenditure.
So they didn’t move less. Their bodies found a way to burn fewer calories at rest. In other words, slower metabolism.
Yes I hate the laws-of-physics “experts” as well. I often want to give some of my knuckle-energy to their faces and see if it converts to extra mass because E=mc^2 said so.
If they say something crazy like “running a mile and walking a mile burns the same number of calories” and then I say “Hmm I’m not really sure if that’s how it works,” that’s the point when they go crazy and just start insulting my lack of physics knowledge.
As a result of many conversations like that, I have developed my own way of dealing with idiots: I just run from them as fast as my puny legs can carry me.
Someone once posted replies from actual physicists about calories. Every one of them said that the laws of thermodynamics can describe the process of weight gain, but tell us nothing about the cause.
If you lift a weight and put it back where you found it, you did zero net work, and yet your muscles are tired. Clearly there is more to it.
Assoc Prof Andrikopoulos is also President of the Australian Diabetes Society, which is still pushing a high-carb diet for Diabetics.
A friend of mine went zero carb yesterday. He had been low carb before and I don’t know why he went so low. After 12 hours he was talking about how much he hated it. Some dope commented to him that it is an unhealthy diet and that your body will start to eat its own muscle mass in order to feed that brain. SMH.
Completely agree!
I was in an aquarium once where the marine biologists had rescued a giant turtle from another zoo as it was dying with peeling skin – apparently there were two similar looking sub-species with completely different diet needs.
The new centre realised this and started feeding – correctly – she got better!
@TreatMeGently
Hi Tom,
“The moral of the story is that calories matter. If you eat more calories, you will put on more weight”
Guess who says that. (via)
From the text of the study: “the increased body weight of mice fed the LCHFD was not associated with a higher energy intake“.
Heh-heh-heh … no surprise there.
But that doesn’t mean carrots are bad for rabbits or humans. It simply means lions are obligate carnivores.
Actually,it does mean carrots are bad for rabbits. They are bad for them due to the sugar content in carrots.
The tops (green part) are ok.
And rabbits are not even rodents.
I suspect the reason rabbits were originally picked on is because they are obligatory herbivorous and true to forum,would react very badly being fed what they were fed so the hot shots could prove their point.
Mice feeding studies can be of use.
Catch and eat mice for example!
Better wild mice than lab mice.
Would this be ok with PETA?
Micky, Mini, and Mighty
Assoc Prof Andrikopoulos is also President of the Australian Diabetes Society, which is still pushing a high-carb diet for Diabetics.
But that doesn’t mean carrots are bad for rabbits or humans. It simply means lions are obligate carnivores.
Actually,it does mean carrots are bad for rabbits. They are bad for them due to the sugar content in carrots.
The tops (green part) are ok.
And rabbits are not even rodents.
I suspect the reason rabbits were originally picked on is because they are obligatory herbivorous and true to forum,would react very badly being fed what they were fed so the hot shots could prove their point.
Mice feeding studies can be of use.
Catch and eat mice for example!
Better wild mice than lab mice.
Would this be ok with PETA?
Micky, Mini, and Mighty
Hey Tom,
Have your read about diabulemia? Just saw this in the news today.
“In fact, Amy has been struggling since high school with diabulimia — an eating disorder wherein people with Type 1 diabetes intentionally restrict their insulin in order to lose weight. “
Haven’t heard that term, but yes, I’ve read about people (particularly teenage girls) skipping the insulin treatment to lose weight. Horrible idea.
Hey Tom,
Have your read about diabulemia? Just saw this in the news today.
“In fact, Amy has been struggling since high school with diabulimia — an eating disorder wherein people with Type 1 diabetes intentionally restrict their insulin in order to lose weight. “
Haven’t heard that term, but yes, I’ve read about people (particularly teenage girls) skipping the insulin treatment to lose weight. Horrible idea.
If someone were to truly feed mice a paleo diet, it would just be, well, whatever the f**k mice eat in the wild, right? I wonder how NZO mice would do in the wild?
Now if we could only figure out what humans ate in the wild…
If only someone would visit some hunter-gatherers and take notes …
It’s a bit tricky in a modern context because hunter-gatherers are highly marginalized and have access to modern technology.
If someone were to truly feed mice a paleo diet, it would just be, well, whatever the f**k mice eat in the wild, right? I wonder how NZO mice would do in the wild?
Now if we could only figure out what humans ate in the wild…
If only someone would visit some hunter-gatherers and take notes …
It’s a bit tricky in a modern context because hunter-gatherers are highly marginalized and have access to modern technology.
Weston Price did that, and even studied semi agricultural societies;
First level takeaway, “Don’t eat the White Man’s food.” That was when the White Man’s food was relatively good compared to today’s.
Hello Tom,
this study just came out about kids and salt. Lots of “associated” in it, plus it only occurred over 24 hours!!
http://journals.cambridge.org/download.php?file=%2FBJN%2FS0007114515005243a.pdf&code=e43af623b12e0390968140bc4db80943
Yeah, I wouldn’t make much of that one.
Hello Tom,
this study just came out about kids and salt. Lots of “associated” in it, plus it only occurred over 24 hours!!
http://journals.cambridge.org/download.php?file=%2FBJN%2FS0007114515005243a.pdf&code=e43af623b12e0390968140bc4db80943
Yeah, I wouldn’t make much of that one.
Quite a few punters taking issue with this “study”. I posted your analysis there too:
https://www.facebook.com/AustinHealth/?fref=ts
I appreciate the plug.
Here is an interview with Prof. Andrikopoulos about this and paleo:
http://www.abc.net.au/radionational/programs/rnafternoons/if-not-paleo,-then-what/7200410
He’s honest about the mice being obese but he’s not really up on research re paleo etc Seems to be a CICO believer.
That doesn’t surprise me … but it’s interesting that in his own study, one group got fatter despite no difference in calorie intake.
Quite a few punters taking issue with this “study”. I posted your analysis there too:
https://www.facebook.com/AustinHealth/?fref=ts
I appreciate the plug.
Here is an interview with Prof. Andrikopoulos about this and paleo:
http://www.abc.net.au/radionational/programs/rnafternoons/if-not-paleo,-then-what/7200410
He’s honest about the mice being obese but he’s not really up on research re paleo etc Seems to be a CICO believer.
That doesn’t surprise me … but it’s interesting that in his own study, one group got fatter despite no difference in calorie intake.
Well, that’s not the conclusion one of the authors, Associate Professor Andrikopoulos, took away from this study:
“The moral of the story is that calories matter. If you eat more calories, you will put on more weight.”
https://pursuit.unimelb.edu.au/articles/paleo-diets-weight-gain
You are not claiming that he is misrepresenting the outcome of his own study, are you?
Goodness, no. A guy who feeds sugar, canola oil and casein to mice and then declares that the results apply humans on a paleo diet could never be accused of misrepresenting his own study.