CICO

The Calorie Paradox: Did Four Rice Chex Make America Fat? (Part II of “There Is No Such Thing As A Calorie”)

Caution: contains SCIENCE!

It’s possible to “prove” just about anything via a blizzard of citations and a few carefully-placed appeals to authority. It’s also easy to become seduced by a plausible and elegant biochemical pathway. Presto: science!

However, when formulating a hypothesis, it’s most important to constrain it by observed reality.

(This is Part II of a series. Click here for Part I.)

Empirical Evidence: “Calorie Math” Doesn’t Work

“ERS data suggest that average daily calorie intake increased by 24.5 percent, or about 530 calories, between 1970 and 2000.” (Source: “Profiling Food Consumption In America”, USDA Economic Research Service.) In absolute terms, the average American was consuming roughly 2150 “calories” per day in 1970, 2260 “calories” per day in 1980—and nearly 2700 “calories” per day in 2000.

Source: USDA ERS

Note that the shape of this curve roughly parallels the prevalence of obesity in America, which increased slowly before 1980 and took a steep upturn afterwards:

It's late and I'm out of witty alt tags.

Note that the upturn in obesity coincides with the US Government’s advice to eat less fat and cholesterol, and more whole grains.

Edible fats contain roughly 3500 calories per pound. Therefore, assuming that people were close to their mythical “daily maintenance calories” in 1970, “calorie math” tells us that the average American gained approximately 800 pounds between 1970 and 2000…and has been gaining one pound per week ever since!

If “calorie math” worked, we would all look like this.

Meanwhile, back in reality, the average adult American gained approximately 19 pounds between 1971 and 2000. (Source: Mean Body Weight, Height, and Body Mass Index, United States 1960–2002, Centers for Disease Control.)

The same “calorie math” says a 19-pound gain in 30 years should require a surplus of just six calories per day. That’s nearly two orders of magnitude smaller than the observed 530 calories per day.

Yes, six calories is enough to stop the obesity crisis! All Americans have to do in order to stop gaining weight is to pull four Rice Chex out of the bowl each morning.

Some say two extra teaspoons of milk are to blame...but that's just plain silly.

I blame the ones hiding under the spoon.

Clearly, “calorie math” doesn’t work.

These are back-of-the-envelope calculations, and are not meant to be exact. And I know some might be tempted to quibble about potential errors in the ERS data: keep in mind that we’re not speaking of a 12% difference, or even a 100% difference. We’re speaking of a nearly 10,000% difference between predicted and observed weight gain.

Yes, I weighed the Rice Chex myself.

Empirical Evidence: “Calorie Math” Doesn’t Work, Part II

We’ve established that the 3500-calorie rule is off by roughly two orders of magnitude for weight gain. It’s also wildly inaccurate for weight loss.

Int J Obes (Lond). 2013 Apr 8. doi: 10.1038/ijo.2013.51. [Epub ahead of print]
Can a weight loss of one pound a week be achieved with a 3500-kcal deficit? Commentary on a commonly accepted rule.
Thomas DM, Martin CK, Lettieri S, Bredlau C, Kaiser K, Church T, Bouchard C, Heymsfield SB.

Despite theoretical evidence that the model commonly referred to as the 3500-kcal rule grossly overestimates actual weight loss, widespread application of the 3500-kcal formula continues to appear in textbooks, on respected government- and health-related websites, and scientific research publications. Here we demonstrate the risk of applying the 3500-kcal rule even as a convenient estimate by comparing predicted against actual weight loss in seven weight loss experiments conducted in confinement under total supervision or objectively measured energy intake.

Their Java applet simulates the average of all the weight vs. time curves extracted from the studies they selected: you can download it here. While it doesn’t account for the differences caused by macronutrient composition (e.g. Ludwig 2012), meal timing (see below), meal composition (see below), or the host of other significant factors, you can amuse yourself by turning on “Show 3500 Calorie Rule” from the Options menu.

Clearly, “calorie math” doesn’t work.

Empirical Evidence: A “Calorie” At Dinner Does Not Equal A “Calorie” At Breakfast

Here’s a fascinating controlled study:

Obesity (Silver Spring). 2011 Oct;19(10):2006-14
Greater weight loss and hormonal changes after 6 months diet with carbohydrates eaten mostly at dinner.
Sofer S, Eliraz A, Kaplan S, Voet H, Fink G, Kima T, Madar Z.

Seventy-eight police officers (BMI >30) were randomly assigned to experimental (carbohydrates eaten mostly at dinner) or control weight loss diets for 6 months.
[…]
Greater weight loss, abdominal circumference, and body fat mass reductions were observed in the experimental diet in comparison to controls. Hunger scores were lower and greater improvements in fasting glucose, average daily insulin concentrations, and homeostasis model assessment for insulin resistance (HOMA(IR)), T-cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) levels were observed in comparison to controls.
[…]
A simple dietary manipulation of carbohydrate distribution appears to have additional benefits when compared to a conventional weight loss diet in individuals suffering from obesity.

How about that?

The officers were eating the same number of “calories”…they were even eating the same balance of protein, fat, and carbohydrate. Yet, the “carbs for dinner” group lost an additional 2.5kg (5.5 pounds) after six months.

Furthermore, this was a deeply restricted diet (1300-1500 “calories”), so we’d expect all the participants to be extremely hungry. (The Minnesota Starvation Experiment fed its volunteers more: 1600 “calories” per day.) Yet the “carbs for dinner” group rated themselves as less hungry and more sated…so real-world results, in which food intake is only restrained by one’s willpower, would be even greater.

Finally, the “carbs for dinner” crowd were healthier in all measured respects: lower abdominal circumference and fat mass, lower fasting glucose and HOMA(IR), lower LDL, higher HDL, and lower whole-body inflammation (CRP, TNF-α, IL-6). All this from a standard “healthy” high-carb diet (20% protein, 30-35% fat, 45-50% carbohydrate), tweaked so that the carbohydrates were eaten mostly at dinner!

Conclusion: a “calorie” of carbohydrate eaten for breakfast is not equal to a “calorie” of carbohydrate eaten for dinner.

According to “calorie math”, the additional weight loss would equal 107 fewer “calories” per day. Apparently you can change the number of “calories” in food just by eating it at a different time of day…

…or perhaps the concept of “calories” is flawed. (I’ll leave the additional problems this experiment poses for reward-based hypotheses of obesity as an exercise for the reader.)

Also note the dramatic alterations to the hormonal milieu: the same authors explore this in more detail in a followup study.

Nutr Metab Cardiovasc Dis. 2012 Aug 14. [Epub ahead of print]
Changes in daily leptin, ghrelin and adiponectin profiles following a diet with carbohydrates eaten at dinner in obese subjects.
Sofer S, Eliraz A, Kaplan S, Voet H, Fink G, Kima T, Madar Z.

Empirical Evidence: A “Calorie” Of Powdered Food Does Not Equal A “Calorie” Of Regular Food

Hat tip to Kindke for this excellent and well-controlled study:

Br J Nutr. 2013 Apr;109(8):1518-27. doi: 10.1017/S0007114512003340. Epub 2012 Aug 6.
Diet-induced obesity in ad libitum-fed mice: food texture overrides the effect of macronutrient composition.
Desmarchelier C, Ludwig T, Scheundel R, Rink N, Bader BL, Klingenspor M, Daniel H.

“The most striking finding was that all mice fed the different powder diets developed obesity with similar weight gain, whereas among the mice fed the pellet diets, only those given the HF and W diets became obese.”

(Note that all mice were fed ad libitum, which means they could eat as much as they wanted.)

Two instructive graphs:

Weight change on standard pelleted diets.

See? High-fat diets cause obesity! (In C57BL/6N mice genetically-engineered to quickly become obese.)

Weight change on powdered diets.

Except when you grind them all into powder—at which point all diets become equally “obesogenic”.

Another fascinating fact: the mice who became obese on the powdered chow were eating the same amount of food that kept them lean when it remained in pellet form! Yes, they were eating the same number of “calories”…

…which made them fat in powder form, but not in pellet form.

We’re not just talking about a little bit of extra fat, either: the mice got 80% heavier on the powdered food, versus 18% on the pelleted version of the same food.

Furthermore, the mice who ate the “high-fat” diet consumed 19% fewer “calories” worth of powdered food—but became just as fat as before. And the mice eating the “Western” diet also consumed 19% fewer “calories”—but became even fatter than before!

Conclusion: a “calorie” of powdered food does not equal a “calorie” of regular food—particularly when the powder is primarily carbohydrate.

Some More Observations On Desmarchelier et.al.

As Kindke notes, flour is powdered carbohydrate. So is sugar. So is almost anything that ends up packaged in a brightly-colored box…processed foods are almost entirely comprised of grains ground into powder, pressed into shape, usually doused with sugar, and baked or fried. Bread, cereal, pasta, donuts, cookies, corn chips, crackers, “instant” anything…yet another reason that Step 1 of “Eat Like A Predator” contains “Do not eat anything made with ‘flour’.”

This study also poses several problems for reward-based hypotheses of obesity. The “high-fat” diet became less “rewarding” when ground into powder, but resulted in the same weight gain. The “Western” diets came in three different flavors, but produced identical results…and all became less “rewarding” when ground into powder, yet resulted in more weight gain. And chow was apparently just as “rewarding” in powder form as in pellet form, yet caused much greater weight gain. (For a demystification of the current state of hunger science, watch my AHS 2012 presentation.)

Finally, here’s a bonus observation. Quote from the paper: “Irrespective of the food texture, the W diet induced a more severe hepatosteatosis and higher activities of serum transaminases compared with the two other diets. In conclusion, diets differing in macronutrient composition elicit specific pathophysiological changes, independently of changes in body weight. A diet high in both fat and sugars seems to be more deleterious for the liver than a HF diet.”

There’s much more—including an indictment of the entire field of obesity research, which has based much on the idea that “high-fat” diets cause obesity. Head over to Kindke’s article to read it.

Conclusions: Our Story So Far

A calorie is not a calorie when you eat it at a different time of day.
A calorie is not a calorie when you eat it in a differently processed form.
Calorie math doesn’t work for weight gain or weight loss.

And we haven’t yet discussed the effects of nutrient partitioning, the mysteries of acronyms like REE, TEE, and TEF, or the myriad other ways in which a calorie is not a calorie. Click here to continue to Part III!

Live in freedom, live in beauty.

(This is Part II of a series. Click here for Part I.)

You. Yes, you. The one who doesn’t yet own a copy of The Gnoll Credo.

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So: BUY IT.

Thank you.

There Is No Such Thing As A “Calorie” (To Your Body)

Caution: contains SCIENCE!

A friend of mine once said “The problem with explaining complicated systems to the layman is this: it’s easy to simplify a concept to the point that that it’s no longer true.”

To that end, I submit the following hypothesis:

The concept of the “calorie”, as applied to nutrition, is an oversimplification so extreme as to be untrue in practice.

What Is A “Calorie”, Anyway?

The dietary calorie is defined as “the amount of energy required to increase the temperature of 1 kilogram of water by 1 degree Kelvin.”

The dietary calorie is actually a “kilocalorie” = 1000 calories, which is why you’ll occasionally see it abbreviated as “kcal”.

It’s an obsolete unit: the “joule” is the modern unit of energy. There are 4.184 joules in a calorie, and 4184 in a dietary calorie (kilocalorie).

Problem: Our Bodies Don’t Use “Calories”

You may already see the problem here: a “calorie” is a unit of energy transfer. We determine the number of “calories” in a food by, quite literally, burning it and measuring how much heat it generates.

This is a bomb calorimeter. Note: not equivalent to the human digestive and metabolic system.

Unfortunately, our bodies are not steam engines! They do not burn the food we eat in a fire and convert the heat into mechanical work. Thus:

There is no biochemical system in our bodies whose input is a “calorie”.

Every metabolic pathway in our body starts with a specific molecule (or family of molecules), and converts it into another molecule—usually consuming energy in the process, not producing it.

This is why we must eat food in order to stay alive. The chemical reactions that build and repair each one of the trillions of cells in our bodies, from brain to toe, from eye to pancreas, require both energy and raw materials. The chemical reactions that allow our cells to perform their necessary functions, from transporting oxygen to parsing visual input to generating muscular force to manufacturing mucus and bile and stomach acid and insulin and leptin and T3, require both energy and raw materials. And the chemical reactions that allow our cells to communicate, via hormones and neurotransmitters, require both energy and raw materials.

In summary, the food we eat has many possible fates. Here are the major ones:

Food can be used to build and repair our tissues, both cellular (e.g. muscles, skin, nerves) and acellular (e.g. hair, collagen, bone mineral).
It can be used to build enzymes, cofactors, hormones, and other molecules necessary for cellular function and communication.
It can be used to build bile, stomach acid, mucus, and other necessary secretions, both internal and external.
It can be used by gut bacteria to keep themselves alive, and the waste products of its metabolism can meet any of the other fates listed here.
It can fail to be digested or absorbed, and be excreted partially or completely unused.
It can be converted to a form in which it can be stored for future use, such as glycogen or fat.
It can be transported to an individual cell that takes it in, and converts it to energy, in order to perform the above tasks.

Note that only the last of these fates—immediate conversion to energy—even approximates the definition of a dietary “calorie”.

Why “Calories In, Calories Out” Is A Radical Oversimplification

By now, the problem with “calories in, calories out” should be obvious:

The fate of a “calorie” of food depends completely on its specific molecular composition, the composition of the foods accompanying it, and how those molecules interact with our current metabolic and nutritional state.

Note that “our current metabolic and nutritional state” is the definition of satiety, as I explain in my ongoing article series “Why Are We Hungry?”, and in my 2012 AHS presentation.

Did you just have an epiphany? I hope so.

So What Matters, If Not “Calories”?

Of the possible fates I listed above, only one is wholly undesirable…storage as fat.

I speak from the modern, First World point of view, in which obesity and the metabolic syndrome are more common health problems than starvation.

And while space does not permit a full exploration of all the possible fates of an ingested “calorie” (it’s called a “biochemistry textbook”), I will give a few examples.

A Few Possible Fates Of A “Calorie”: Protein

Imagine a molecule of “protein”.

Proteins are made up of chains of amino acids. (Learn more about proteins and their structure here.) Some proteins, such as meat, are readily digested and absorbed. Some are poorly digestible, such as the prolamins found in grains like wheat and corn, and part of them will either feed gut bacteria or be excreted. Then, once protein is absorbed, its composition of amino acids determines how much of the protein we can use to build and repair (the first three fates in the list above), and how much must be burned for energy or excreted.

The amino acid composition of grains is different than what our bodies need, since the metabolic needs of a grass seed are very different than the metabolic needs of a human being. That’s why grains score so low on measures of protein quality, such as the PDCAAS, compared to meat and eggs. (Grains score 0.25-0.4, versus approximately 1.0 for all animal-source proteins.)

But even if the protein is perfectly digested, absorbed, and of high quality, that is no guarantee of its fate! If we’ve already absorbed enough complete protein for our body’s needs, additional protein will still be converted to glucose, burned for energy, or excreted, no matter how high its quality. (Our bodies have no dedicated storage reservoir for protein…the process of muscle-building is very slow, and only occurs when stimulated by the right kinds of exercise.)

So, right away we can see that a “calorie” of meat protein that is digested, absorbed, and used to build or repair our bodies is not equal to a “calorie” of meat protein surplus to our needs. Nor is it equal to a “calorie” of wheat protein that is only partially digested, poorly absorbed, and disruptive to the digestive tract itself! (e.g. Fasano 2011)

A Few Possible Fates Of A “Calorie”: Fructose

(Again, space does not permit a full exploration of all possible fates of all possible types of “calories”, so these explanations will be somewhat simplified.)

Imagine a molecule of fructose.

Under ideal conditions, fructose is shunted immediately to the liver, where it is converted into glycogen and stored for future use. However, fructose has many other possible fates, all bad. It can fail to be absorbed, whereupon it will feed gut bacteria—a process that can cause SIBO, and consequent acid reflux, when continued to excess. If our liver is already full of glycogen, fructose is converted to fat—a process strongly implicated in NAFLD and visceral obesity. And when our liver is overloaded with fructose (or alcohol, which uses part of the same metabolic pathway), it can remain in circulation, where it can react with proteins or fats to form AGEs (advanced glycation endproducts), useless and/or toxic pro-inflammatory molecules which must be filtered out by the liver.

A typical Big Gulp contains over 100 grams of HFCS. Even the typical “healthy” fruit smoothie contains over 90 grams of high-fructose fruit sugar!

An adult liver can only store, at most, 100-120g of glycogen…and our bodies never let it become deeply depleted.

The problem here should be obvious.

Now ask yourself: which of the above fates has any meaning relative to the definition of a “calorie”?

A Few Possible Fates Of A “Calorie”: Starch

I can’t possibly explore all the fates of starch, but here are some common ones.

Starch is made of glucose molecules chained together. Upon digestion, it’s broken down into these individual glucose molecules, and absorbed—usually reasonably well, unlike fructose (though certain forms, called “resistant starch”, are indigestible and end up being used for energy by our gut bacteria).

Once glucose enters our bloodstream, its fate depends on a host of metabolic and nutritional factors. Ideally, because high blood glucose is toxic, our muscles and liver are not already full of glycogen, and insulin will quickly force it into one of them, whereupon it will be stored as glycogen and used as needed. Our brain and red blood cells also need glucose, since they can’t run on fat, and if they’re low on energy they can burn it too.

Unfortunately, as we’ve seen, our liver has a very small storage capacity, and the capacity of our muscles isn’t very large either—1-2% of muscle mass.

A 155 pound (70 kilo) adult at 14% bodyfat will contain about 66 pounds (30 kg) of muscle, leaving him with 300-600 grams of glycogen storage, depending on his level of training. (Source.)

Note that only reasonably intense exercise (> 50% VO2max) significantly depletes muscle glycogen, and only from the muscles used to perform the effort. Also note that the mainstream recommendation of 50-60% of daily “calories” from carbohydrate equals 300g-360g for a 2400 “calorie” diet.

Again, the problem here should be obvious.

Then, our cells will try to switch over to burning the surplus of available glucose, instead of burning fat for energy.

People with impaired metabolic flexibility have a problem switching between glucose and fat metabolism, for reasons that are still being investigated.

This is yet another example of how our nutritional and metabolic state affects the fate of a “calorie”; why a “calorie” of fat and a “calorie” of sugar are not equivalent in any sane sense of the word; and why different people respond differently to the same number and composition of “calories”.

Next, our body will try to “rev up” our basal metabolic rate in order to burn off the excess glucose…if sufficient cofactors such as T3 are available, and if our metabolic flexibility isn’t impaired. And a continued surplus will be (slowly) converted to fat in either the liver or in fat cells…but if it remains in circulation, it can react with proteins or fats to form AGEs (though more slowly than fructose).

Note that these proteins and fats can be part of living tissues: neuropathy, blindness, and all the complications of diabetes are consequences of excessively high blood sugar over the long term.

Are you starting to understand why the concept of a “calorie” is so oversimplified as to be effectively meaningless?

A Few Possible Fates Of A “Calorie”: Fat

Explaining all possible fates of all possible fats, even cursorily, would require an even longer section than the above two! However, I trust my point is clear: the fate of dietary linoleic acid differs from the the fate of DHA, the fate of palmitic acid, or the fate of butyrate, and their effects on our nutritional and metabolic state will also differ.

But Wait, There’s More

I also don’t have time or space to explore the following important factors:

Energy loss when food is converted to different forms of storage (e.g. gluconeogenesis, glycogenesis, lipogenesis) or retrieved from storage
How different types and quantities of dietary protein, fat, and carbohydrate affect our hormonal and metabolic environment
How the fate of a “calorie” depends on the composition of the other foods it’s eaten with
How different types and quantities of food, as well as our nutritional and metabolic state (our satiety), affect our perception of hunger
The host of known, measurable differences between individuals, such as MTHFR genes, the respiratory quotient, and the bewildering variety of hormones on the HPTA axis.

Conclusion: The Concept Of A “Calorie” Is So Oversimplified As To Be Meaningless

Let’s recap some of the possible fates of a “calorie”:

Food can be used to build and repair our tissues, both cellular (e.g. muscles, skin, nerves) and acellular (e.g. hair, collagen, bone mineral).
It can be used to build enzymes, cofactors, hormones, and other molecules necessary for cellular function and communication.
It can be used to build bile, stomach acid, mucus, and other necessary secretions, both internal and external.
It can be used by gut bacteria to keep themselves alive, and the waste products of its metabolism can meet any of the other fates listed here.
It can fail to be digested or absorbed, and be excreted partially or completely unused.
It can be converted to a form in which it can be stored for future use, such as glycogen or fat.
It can be transported to an individual cell that takes it in, and converts it to energy, in order to perform the above tasks.

Note that only the last of these fates—immediate conversion to energy—even approximates the definition of a dietary “calorie”.

I hope it is now clear that the fate of a “calorie” depends on a bewildering host of factors, including our current nutritional and metabolic state (our satiety), the composition of the other foods it’s eaten with; our biochemical individuality, both genetic and environmental; and much more.

Takeaways

There is no biochemical system in our bodies whose input is a “calorie”.
The food we eat has many possible fates, only one of which approximates the definition of a dietary “calorie”.
The fate of a “calorie” of food depends completely on its specific molecular composition, the composition of the foods accompanying it, and how those molecules interact with our current metabolic and nutritional state—our satiety.
Therefore, the concept of the “calorie”, as applied to nutrition, is an oversimplification so extreme as to be untrue in practice.
Therefore, the concept of “calories in, calories out”, or CICO, is also unhelpful in practice.
The health-supporting fates of food involve being used as raw materials to build and repair tissues; to build enzymes, cofactors, and hormones; to build bile, mucus, and other necessary secretions; to support “good” gut bacteria, while discouraging “bad” bacteria; and, once all those needs are taken care of, providing energy sufficient to perform those tasks (but no more).
Therefore, we should eat foods which are made of the raw materials we need to perform and support the above functions.
Biochemical individuality means that the optimum diet for different people will differ—as will their tolerance for suboptimal diets.
However, eating like a predator—a diet based on meat, fish, shellfish, vegetables and fruit in season, and just enough starch to support your level of physical activity—is an excellent starting point.

Live in freedom, live in beauty.

This is a multi-part series. Continue reading Part II, “Did Four Rice Chex Make America Fat?”

ATTENTION! Before reflexively commenting that “A CALORIE IS A CALORIE BECAUSE SCIENCE!!11!!!1!”, you are required to read both the comments below (in which I address many such questions)—

—and, more importantly, the peer-reviewed research contained in Part II, Part III, Part IV, Part V, Part VI, Part VII, and Part VIII. (And there’s more to come.)

Yes, metabolism is complicated. Deal with it.

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