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...Tell Me More
Yesterday’s post introduced the major myths surrounding calories, weight loss, and human regulation of body weight, but there are some other serious misconceptions surrounding the topic that need clearing up. People can really get down on themselves when they listen to all the “experts”. They’ll weigh, measure, and count themselves into oblivion only to experience middling weight loss. Or maybe they lose weight but their energy tanks, their performance in the gym suffers, and their belt size doesn’t get any better, suggesting muscle loss. They’re basing their decisions and actions on myths, and myths just don’t work. These myths do real harm, so it’s important to destroy them.
Today, I’m going to focus on nine more.
The way many people envision it, the only thing food does is provide energy for storage or immediate use.
But food is more than energy.
Protein, for example, is broken down into amino acids which provide the building blocks for human cells, muscles, and tissues. And yes, in extreme cases protein can provide energy, either through direct metabolism of the amino acids or conversion into glucose, but the vast majority of the protein we eat is directed toward structural roles. We build things with protein. And even when we do “burn” protein for energy, it’s not very efficient.
Food provides energy and raw material for building important things like muscle, cellular membranes, hormones, nerves, neurotransmitters, sperm, tears, new eyelashes, beards, or toenails. Anything the body does, or makes, or metabolizes, like convert serotonin into melatonin so you can fall asleep at night, requires both energy (to power the process) and raw materials. Food is both.
And even when food is “just” energy, it’s “metabolizable energy.” You have to expend energy to extract energy from that sweet potato and steak you just ate. It’s not gross energy.
Since we all agree that weight loss requires that a person expend more energy than they take in, counting them should be the only way to lose weight. Nearly everyone can count and do basic math, so why not just do a little addition and subtraction? Once the stark reality of the numbers lies in front of you and the true, physics-backed path to healthy weight loss reveals itself, you’d have to acquiesce and give in and stop eating so much, you glutton, because Science implores you to and no one can deny Science.
The latest low-fat/low-carb diet study contradicts this: participants in the low-carb arm were told not to restrict calories by the researchers, yet calories were restricted and weight was lost. Detractors often point to this as proof that calories indeed matter. To me, this showcases that active consideration of calories is unnecessary. They lost weight and reduced calories without counting calories. That’s the good stuff, right?
Heck, even when you compare a strict calorie-counting diet with an ad libitum (“at liberty”) low-fat, high-carb diet, the calorie counters lose out and the ad libitum dieters have better weight loss retention after 2 years. Calorie counting just doesn’t work for most people.
Gotta love that phrase, “at the end of the day.” People drop this in comment sections and that’s that: the debate is over, the argument won. Go home.
Except is that really the case? “Weight” is so non-specific. You might gain bone. You might gain muscle. You might gain glycogen. You might gain organ weight. You might gain newly repaired intestinal lining. And yeah, you might gain fat, but it’s not a foregone conclusion just because you “gained weight.”
Imagine if you had to maintain conscious control over every physiological process in your body. When you walked, you’d say to yourself “step left, step right, step left, step right” all day long or you wouldn’t get anywhere. To provide oxygen to your body, you’d have to remember to breathe in and breathe out every few seconds. An hour or so before bedtime, you’d will your pineal gland to begin secreting melatonin so you could sleep. After eating, you’d have to alternately engage and relax your peristalsis muscles to create the undulation that forces food along the digestive tract. Performing a squat would require conscious orchestration of the contraction of dozens of agonist, antagonist, stabilizer, and synergist muscles at once. Life would get pretty unwieldy, wouldn’t it?
So where do we get the idea that eating – one of the most basic and essential physiological processes – requires constant vigilance and number crunching? What did people do before the concept of a calorie was invented?
In metabolic ward studies where calories are counted for you and food is strictly weighed, measured, and provided by the researchers, calorie counting works pretty well. Subjective feelings of appetite are immaterial when you only have access to the food provided and you can’t leave to get more.
In the real world, calorie counting doesn’t work as well. If a free-living guy is ravenous from counting calories and he drives past a McDonald’s, he has the option of stopping in for a McDouble (they still make those, right?) and fries. If a subject in a metabolic ward study is ravenous from having his calories counted for him and he has a fever dream of Ronald McDonald hand-feeding him fresh french fries, it doesn’t matter because he doesn’t have the option of eating any more food.
Besides, it’s not even possible to do it accurately without direct measurement. A group of normal weight men and women were blinded to one of two treadmill exercise sessions (burning either 200 or 300 calories). After the workout, they were taken to a buffet and told to eat as many calories as they’d just burned exercising. Both groups failed miserably.
First of all, they thought they’d burned way more calories than they actually had. The 200 calorie group guessed they’d burned around 825 calories. The 300 calorie group guessed close to 900 calories.
Second, they ate fewer calories than they estimated, but more than they actually burned. Every estimate they made was inaccurate.
And that was in normal weight individuals, the people who are least likely to have broken metabolisms and dysfunctional satiety mechanisms. If they can’t accurately predict energy intake and expenditure, how is anyone supposed to? According to many researchers, self reports of calorie intake and expenditure are “so poor” that they’re more harmful than not even trying to count.
For the most part, people all have the same basic physiological machinery. We all metabolize carbs, fat, protein, and other nutrients along the same pathways. We all use insulin to sequester glucose into cells, for example (even people who don’t produce insulin will respond to injected insulin).
That said, we all have different capacities for using these pathways.
For instance, most overweight or obese people seem to do best on lower-carb, higher-fat diets. The literature is pretty clear on that. If you’re insulin-resistant and overweight (which is most of the overweight population), going low-carb is the best, easiest way to control hunger, spontaneously reduce food intake, and lose weight and, most importantly, body fat. Hundreds of success stories from this site and others are further testament to that.
However, the relatively rare insulin-sensitive obese phenotype does better on calorie-counting low-fat diets. If you’re obese and insulin sensitive, you’ll probably be able to lose more weight eating more carbs. That’s just a fact, and it’s just more proof that macronutrient ratios, personal history, hormonal status, and genetic background are relevant to the impact of calories.
Another example: Say you’ve got two men, both weighing 200 pounds and standing 6 feet tall. The first is active, fit, and muscular, sitting at 11% body fat. The second is sedentary and overweight, sitting at 30% body fat. If they eat an equal amount of baked potato, will those carbohydrates enjoy the same fate in both men?
The first guy has significantly more muscle. That means larger glycogen stores, the only way to store carbohydrate. The second guy has significantly less muscle, meaning he has less room to store carbohydrate as glycogen. Assuming both are equally glycogen depleted, in whose body will the greater portion of carbohydrates be sequestered as body fat?
The first guy is more likely to store the carbs as glycogen because his larger muscle mass confers greater storage capacity. The second guy is more likely to convert the carbs to fat. Once his liver and muscle glycogen stores fill up, any glucose that isn’t immediately used for energy will be converted to fat. This isn’t a huge acute contribution to overall fat gain, but it does illustrate the different metabolic fates the same number of calories can have in two different people of equal weight.
And we all know that guy who can eat a 2000 calorie meal without gaining an ounce. If you sit next to him while he eats, you can literally feel the heat emanate from his body. Or maybe he’ll start fidgeting, or get up to pace the room. Kids are often like that. You feed them a big meal and they’ll be whizzing around the room, not to “burn the calories off to avoid weight gain” but because they just received a large influx of energy and it’s only natural for a kid to use it. That used to be me back in college.
Exercise affects appetite and inadvertent calorie intake differently in men and women. In men, the higher the exercise’s intensity, the lower the appetite. This is true across most studies. But there’s also evidence that in women, intense exercise — sprints, HIIT, circuit training — actually has the potential to increase appetite and energy intake.
This is where we start getting somewhere. Most people will admit that different ratios of macronutrients (protein, fat, carbs) in the diet can affect weight loss. This is why bodybuilding cutting diets are made up of chicken breast and broccoli, not Coke and pizza. But they’ll go no further than talking protein, fat, and carbs.
In reality, different subtypes of protein, carbs, and fat have different metabolic effects. Take protein. Whey promotes energy expenditure relative to other proteins, like tuna, egg, or turkey. Other studies have found that both whey protein and pea protein suppress the appetite to a greater degree than milk protein or a combination of whey and pea protein. Meanwhile, fish protein eaten at lunch suppresses subsequent energy intake more than a beef protein lunch.
Take carbs. In one (rat) study, isocaloric amounts of honey and table sugar had different effects on bodyweight. The rats who ate honey gained less bodyweight and body fat (particularly that really hard-to-burn epididymal pad fat we all hate so much!) than the sugar-fed rats.
Take fat. In one study, isocaloric amounts of either industrial (not grass-fed ruminant) trans-fat or a blend of monounsaturated and saturated fat were given to human subjects. Those eating the trans-fat experienced greater increases in body fat and waist circumference. There was no difference in overall bodyweight, of course, so I guess the CICO fanatics “win” this one, but the two different fat sources clearly had different metabolic fates.
There are more examples of each, but even just one is enough to dismantle the claim.
Lost in all the blog chatter about this or that study is the fact that the faceless participants whose bodies we’re discussing are individuals. The individual experiences of these individual subjects dissolve into the mean, the average presented in the abstract. If you’re lucky, you’ll get a +/- indicating the range of responses. But every subject from every study ever conducted has had unique reactions to the experiment.
For instance, there’s the “single low-calorie subject” from this study who experienced no reduction in liver fat. Everyone but him saw improvements. Should that guy disregard his own experience because the study’s conclusion about the effect of dieting on liver fat in the “average person” said otherwise?
You are not a statistic. This goes for every study out there, but it’s especially pertinent for diet studies. I know many people who’ve had paradoxical responses to various dietary interventions, responses that the studies don’t really capture. Are they all lying?
Sometimes, I like to dream that we’re bomb calorimeters.
Our stomachs are buckets full of water (that’s where those “the human body is 75% water” claims originate). Suspended inside those stomach buckets is a smaller sack, called a bomb. A tube runs from our mouths and feeds directly into the bomb. When we eat something, the food goes down the tube and into the bomb. As we chew, a series of tendons attached to our jaws rub together to produce a spark. The heat travels down into the bomb to ignite the food. A separate tube runs from our lungs to the bomb carrying pure filtrated oxygen. The food combusts and the heat generated is distributed throughout the body to give us energy. The beauty of digesting our food in the bomb is that it’s a closed system, shut off and free of influence from the outside universe, so we know that what we put into the bomb is exactly what we’ll get out of digesting it. Meat, potatoes, kale, Pepsi – it’s all pure unadulterated raw fuel and it all burns equally. It’s all heat energy.
Unfortunately, that’s not how the human body works.
I contend that no one truly believes “a calorie is a calorie.” Even the researchers who claim perfect parity between different caloric sources in esteemed scientific journals contradict themselves in their own papers.
We conclude that a calorie is a calorie. From a purely thermodynamic point of view, this is clear because the human body or, indeed, any living organism cannot create or destroy energy but can only convert energy from one form to another.
No argument here.
In comparing energy balance between dietary treatments, however, it must be remembered that the units of dietary energy are metabolizable energy and not gross energy. This is perhaps unfortunate because metabolizable energy is much more difficult to determine than is gross energy, because the Atwater factors used in calculating metabolizable energy are not exact. As such, our food tables are not perfect, and small errors are associated with their use.
“Small errors.” Mistakes were made, nothing to see here, move along. Don’t worry yourself over the margins. It all evens out in the end.
In addition, we concede that the substitution of one macronutrient for another has been shown in some studies to have a statistically significant effect on the expenditure half of the energy balance equation. This has been observed most often for high-protein diets. Evidence indicates, however, that the difference in energy expenditure is small and can potentially account for less than one-third of the differences in weight loss that have been reported between high-protein or low-carbohydrate diets and high-carbohydrate or low-fat diets.
It’s just “one third” of the difference in weight loss. That’s nothing at all!
As such, a calorie is a calorie.
Even though we just explained how a calorie is not a calorie, a calorie is a calorie.
Further research is needed to identify the mechanisms that result in greater weight loss with one diet than with another.
In other words, our simplistic “calories in, calories out” approach is inadequate and other mysterious “mechanisms” are responsible for the difference in weight loss between diets. But trust us, a calorie is still a calorie!
We’re all on the same page here. Some of us just can’t admit it.
Thanks for reading, everyone, and let me know what you think in the comment board!
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