What controls body composition?
Summary
Although the conventional wisdom is that ice baths will promote weight loss by stimulating cold thermogenesis, this view is too simplistic.
Deliberate cold exposure will promote metabolic health, but not necessarily fat loss, because body composition (i.e., fat versus muscle) is controlled by chemical and electromagnetic signaling, not overall energy balance. Similarly, a keto diet can promote fat burning, but still be unhealthy overall.
Practices that maintain healthy body composition must align nutritional and energetic drivers to match ancestry and season. For example:
Avoid eating plant leaves, stems, root, seeds, and their extracts -- including oils like corn, cottonseed, canola, and safflower oil. Human beings are not equipped with the gastrointestinal tract necessary to detoxify these parts of the plant, and so they must be considered foods of last resort.
Get more sunlight. Longer wavelengths (near infrared) in the morning and evening, with shorter wavelengths (ultraviolet) in the middle of the day, works best.
Eat like your ancestors. For example, Northern Europeans thrived on dairy year-round, but did not eat the fruit oils (e.g., olive, coconut, or palm) that populations in warmer climates did. Everyone ate fish, which works in all seasons, and our ancestors probably ate more waterfowl than we do now.
Practice deliberate cold exposure to maintain insulin sensitivity, brown fat, and regulate thyroid function. Don't count on it for weight loss.
Finish your ice bath practice with exercise. You will enjoy the increased energy and performance gains that pre-cooling affords, and boost your testosterone levels to signal your body to reduce fat and build muscle.
Your thoughts are the most important mechanism for signaling your body composition. Eat foods that sate your appetite for great food, until you believe you've eaten more than enough.
Metabolism vs weight
According to Mike Mutzel, founder of High Intensity Health, weight is an unreliable indicator of metabolic health. For example, on a calorie-restricted, high carb diet, even extremely thin people can develop Type 2 diabetes. Conversely, a person with high body fat percentage can nevertheless show all the markers of metabolic health -- especially when they maintain active brown fat (e.g., Herz et al. 2022).
I probably fit into that latter category.
When I finally decided to get serious about my weight, I dropped from a high of 249lbs down to less than 195lbs. Although I was still overweight for my nearly 6ft height, I enjoyed compliments from people who said how much better I looked.
When I started ice baths, my health, my energy, and my testosterone levels all jumped to levels I hadn't experienced in decades -- so there's no doubt I was getting healthier.
Nonetheless, I doubt ice baths are helping me keep the weight off. I've gained more back than I expected, and I now bounce around at about 215lbs.
What's going on?
The caloric fallacy
The dominant theory of dieting is the calories-in-calories-out (CICO) hypothesis. According to this theory, fat volumes in the body are governed by a thermodynamic energy balance such that when energy intake exceeds energy expenditure, the surplus is stored as increased lipid droplets in our fat cells. It follows that the converse should also be true -- that is, to lose weight, a body must burn more calories than it eats.
The simplicity of the CICO hypothesis is very appealing. It encourages overconfidence by extending our understanding of machines to complex human systems. What's more, data from scientific studies shows that a caloric deficit can result in weight loss, which seemingly offers proof that "a calorie is just a calorie" (e.g., Howell & Kones 2017).
Nevertheless, the CICO hypothesis is a radical oversimplification of the human metabolism. There are several misconceptions that, when corrected, cause re-examination of existing data. The most obvious of these is the difficulty of measurement. For example, the precision with which nutrition information (e.g., food calories) and calorie-burning calculators purport to provide CICO data misrepresents their accuracy. In fact, nutrition labels and calorie counters are at best rough approximations.
The laboratory equipment used to measure the energy content of food is called a bomb calorimeter. It works by incinerating food, measuring the heat of combustion, and correcting the thermal measurements to estimate "metabolizable" energy to account for caloric loss via "obligatory losses in feces and urine" (Urban et al. 2011). So it's no wonder that nutrition labels are mere approximations.
Estimates of calories burned are even less accurate, because they fail to account for compensating metabolic adjustments. For example, there is evidence in mice that suggests increased energy expenditure during cold exposure is compensated for by reduced energy expenditure at other times (e.g., Presby et al 2019). Similar compensatory mechanisms have been measured in humans in which increased metabolic efficiencies result from increased exercise and/or diet (e.g., King et al. 2012). Thus, it is possible that the increased energy expenditure measured during and after deliberate cold exposure is compensated for by decreased energy expenditure while sleeping at night.
Somewhat less obvious, and more important, is that calories are the crudest of all thermodynamic measures. Even if the quantitative measurements of intake and expenditure were exactly correct, they'd be insufficient to explain weight gain or loss because bomb calorimetry destroys the complexity of food. For example, calorimetry cannot distinguish between amino acids and complex proteins. It treats saturated and unsaturated fats as almost identical, and it makes no allowances for variations in digestive microbiome or lactose tolerance.
Cold thermogenesis for burning calories
It should be obvious that human digestion does not work like bomb calorimetry. Nevertheless, the dominant theory of deliberate cold exposure for weight loss all focus on the fact that cold thermogenesis is effective for energy expenditure.
While the logic of the CICO hypothesis sounds convincing, the cold thermogenesis theory of weight loss is unlikely to achieve results. That might explain why regular practitioners of deliberate cold exposure like me fail to see dramatic weight loss during a regular, documented, and intense ice bath practice. That is, despite the effectiveness of caloric deficit for weight loss, and despite the increased metabolic expenditure of calories during cold exposure, it is now evident that:
Deliberate cold exposure alone is not a reliable strategy for weight loss -- even though it does result in reliable improvements in metabolic and cardiovascular health.
Your body responds to information
The problem with the CICO hypothesis is that it ignores information signaling. As Dr. Bruce Lipton (Biology of Belief 2005) points out, the cells in your body have no choice but to respond to their biochemical and electromagnetic environment. Because simple cells, including those in your gut microbiome, do not have their own consciousness, they must respond to chemical and electrical exposures in accordance with material laws of physics.
Thus, every chemical, sensory, and electromagnetic exposure creates a signal to which the body must respond. Food, medicine, and poison are all chemical signals. Temperature, taste, sound, and touch are a sensory signals. Light, electricity, magnetism, are electromagnetic signals. (There are even quantum signals that transcend the conventional electromagnetic spectrum, e.g., Hunt 2020).
For example, it is well known that weight lifting results in increased muscles mass.
By what mechanisms does this happen?
When muscles are fatigued, a constellation of biochemical responses take place that signal the body to repair, replace, and rebuild new muscle tissue. Thus, body composition is not controlled by energetic balance, but by the information signals that guide energy into synthesis of protein, bone, fat, or water. Because it is body composition (Steinach & Gunda 2020) that we are really seeking to manage, not weight, we must master the practices that signal the body to guide more food energy to building muscles, and less to maintaining fat.
To this end, food plays three critical roles in controlling body composition. They are:
Food as information, signaling the body and its microbiome (Yong 2016) how to adapt to the environment for better survival and reproduction.
Food as material, providing the body with the building blocks necessary to synthesize essential components, including structural cell membranes, internal organs, organelles like mitochondria, bones, muscles, and connective tissues.
Lastly, food as energy for fueling the metabolic processes on which life depends.
Food is best understood as information first, material second, and energy last.
The molecules in food dictate the response of your gut microbiome and the cells in your body in the same way that you expect medicine or poison to create reliable physiological responses. In other words, the food you eat instructs your body in different ways -- including what level of hormones to produce to build muscle for hunting versus fat (to prepare for periods of starvation).
Thinking beyond macronutrients
Traditional dieticians recognize three basic macronutrients: carbohydrates, fats, and proteins.
Carbohydrates are the simplest foods and contain little information value. Digestible carbohydrates like sugar and starches are used by the body almost exclusively as energy, while non-digestible fibers pass through the body into the feces. Contrary to conventional diet advice, there is no minimum required dietary intake of carbohydrates necessary to support human health, because the liver is capable of synthesizing glucose for all metabolic processes that require it. In fact, the liver uses glycerol obtained from fat cells to synthesize glucose, suggesting: The need for gluconeogenic substrate (during very low carbohydrate diets) may explain how lipolysis can continue when caloric intake exceeds caloric expenditure. -- Westman et al. (2003).
Fats are more complex. They come in a dizzying array of varieties, including saturated, monounsaturated, polyunsaturated, and trans fats, all of which signal different metabolic and informational pathways within the body.
Proteins are the most complex. At their most basic, proteins are constituted by a long string of amino acids that make up the chemical formula of the protein molecule. However, information is also contained in the secondary structure of protein molecules (folding patterns along the length the amino acid chain), tertiary structure (three dimensional structure of the protein) and quaternary structures (combinations of proteins that fit together).
Ketone esters and salts (i.e., exogenous ketones) can serve as a fourth category of macronutrient (Christofferson 2020), although these exist as only supplements, rather than in natural foods.
Within each macro-category of nutrients, there are subcategories that can have different effects on health and body composition. No one has popularized this realization better than Dr. Paul Saladino, who has experimented with vegan, carnivore, and what he calls "animal-based" diets. Rather than make complicated chemical distinctions to identify nutritional subcategories, Saladino separates macronutrients into simpler general categories:
Seeds, roots, leaves, and stems are not well-suited for human consumption, because plants incorporate chemical defenses into these parts of their organism to discourage predation. Animals that forage on these foods (e.g., cows, gorillas) need extensive digestive tracts to detoxify them. Human beings, with our comparative small stomachs, are ill-equipped to digest these macronutrients.
Beans, nuts, grains, and the flours ground from them are seeds, so they belong in this category of foods to use only as a last resort. Most importantly, this category also includes seed oils (i.e., so-called vegetable oils like corn, cottonseed, soy, peanut, and sunflower oils). Not only are these oils extracted from seeds -- which plants are evolutionarily adapted to defend -- but their production requires chemical processing to detoxify and preserve them. The result of seed oils extraction is a barely edible fat poorly suited as building blocks for cell membranes, and vulnerable to toxic cross-linking during heating.
Despite the fact that seed oils are technically ketogenic, they must be avoided. Unfortunately, they're cheap and consequently ubiquitous.
Fruits and berries package their seeds with an energy-rich layer of food called the endocarp that offers foragers a nutritional reward when eaten. Fruit seeds are typically well-defended against digestion, so that the animal or human who eats the entire fruit may pass the seeds in their nitrogen-rich feces, where it will germinate into a new fruit plant. In this way, fruit and berry plants are evolutionarily adapted for a mutualistic relationship with their predators.
This may also explain why fruit oils, like olive, coconut, and palm oils, can be healthy dietary supplements, even though seed oils remain toxic. Fruit oils are extracted from the parts of the plant that are evolutionarily advantageous for eating. Thus, grapeseed oil (extracted from the pit of the grape) is tasteless and toxic, while olive oil (extracted from the endocarp of the olive, not the pit) is delicious and healthy.
Dr. Saladino includes fruits, berries, and fruit oils in his "animal-based" diet, presumably because these foods are healthy for animals, if not derived from them.
Animal fats, in contrast to seed oils, are healthy for human consumption. The best animal fats are from wild animals and fish, compared with farm-raised. For example, cod-liver oil is extracted from cold water fish that roam the north Atlantic. It is especially rich in omega-3 fatty acids that make good the structural basis of cell membranes and brain tissues.
Animal proteins are highly prized, nutrient-dense foods that could be further divided into skeletal muscle and organ meats. The most popular of these as the skeletal muscles that are cut into steaks, chops, and roasts. The organ meats (liver, kidney, heart, tongue, brain) may be preferable as sources of nutrients, but many people find their taste or texture unpalatable.
What signals changes in body composition?
Food is just one signaling mechanism for the body. Other signaling mechanisms include light, temperature, other biochemical exposures, and exercise. When these signals are discordant -- for example, light signaling and food signaling are pushing energy into different compartments of the body -- disease can persist within the body.
Exercise We've already discovered that exercising after your ice bath is effective for boosting testosterone. By contrast, an ice bath without exercise afterwards can suppress testosterone. Because increased testosterone is associated with increased muscle mass, decreased visceral fat, overall improvement in energy levels and body composition, one of the most important signals you can send your body is to use exercise to recover from your cold exposure, rather than the other way around.
Temperature, Light, Diet Seasonality Perhaps the key to improving body composition further is to align the remaining signals to result in healthier outcomes. Most people assume that light, food, and temperature are all moving together in seasonal rhythm. As days get shorter, plants die (or go dormant), while temperatures drop, thus fruits are less plentiful and ancestral human diets must have switched from complex carbohydrates to fat and protein.
That assumption might suggests that a daily practice of deliberate cold exposure does not accord with seasonal variations, and would put temperature out of alignment with food and light signaling. However, in 'Cold water immersion may have shaped our evolution', I explained that our ancient East African ancestors likely emerged from a semi-aquatic cold water existence.
The Aquatic Ape Hypothesis explains why humans walk upright, have subcutaneous fat (like whales and dolphins), downward-facing nostrils, and less hair and more webbing between their fingers and toes than other primates to whom we are closely related. These anatomical advantages would make it easier for early Homo Sapiens to wade, swim, and dive through the cold, glacier-fed streams of East Africa in search of water-based prey like fish, shellfish, and waterfowl.
That means that in even in the equatorial climates from which we evolved, ancient humans would have experienced acute cold water exposure -- a pattern that must have persisted among my North Sea ancestors, who would have no doubt experienced cold water immersion regularly during their summers.
Although eating keto or carnivore all of the time is now in fashion, my ancestors must've eaten fruits and berries during the growing season. It's hard to imagine a Grandma Seager from 10,000 years ago eschewing the delicious fruits and berries that were plentiful in the summer, when temperatures are warm and solar energy is plentiful. Therefore, adding fruits berries back into my diet this summer when days are long and I'm getting plenty of light exposure might improve my evolutionary alignment. By contrast, air freighting Chilean blueberries to Arizona in the winter is an evolutionary abomination.
While the carbohydrate content of seasonal fruits will shift my body to glucose metabolism (out of ketosis) in the summer, according to Saladino, that shift is part of the natural seasonality to which I am evolutionarily adapted.
But what about the risks of insulin spike associated with high carbohydrate foods like fruit?
Continuing my summertime ice bath practice will prevent the premature mitochondrial ageing associated with high carbohydrate diets by maintaining high insulin sensitivity and clearing glucose from my bloodstream. Therefore, an ice bath practice during the summer is consistent with my evolutionary biology and essential to my metabolic and mitochondrial health.
Dairy fat vs fruit oils Another peculiar trait specific to people of Northern European descent is very important. About 7,500 years ago, my ancient ancestors developed a unique mutation allowing them to digest lactose (a carbohydrate) in milk as adults (Curry 2013). While the old Vikings had zero dietary contact with coconuts, avocados, and oily fruits, the dairy mutation would have allowed them to continue to drink milk all winter -- as long as they had stored enough hay for their cows to make it.
Therefore, despite dietary advice professing the health of the fruit oils that grow around the Mediterranean, for me it may be that use of tropical fruit oils is discordant with the diet our bodies have been evolutionarily adapted to expect. For those descendant from warmer climates where olives, avocados, and coconuts are available, fruit oils may be a good choice in the winter.
And "Seafood," according to Dr. Jack Kruse, "is always a good choice no matter what season we are in."
The ultimate signal?
Finally, there is one additional mechanism for signaling body composition: our thoughts.
Dr. Joe Dispenza is one of the most popular experts on the importance effects thoughts have on our health. In You Are the Placebo (Dispenza 2014), he describes the placebo and nocebo effect, in which he demonstrates that positive (placebo) and negative (nocebo) thoughts have corresponding health effects. Nonetheless, one of the most dramatic illustrations of the power of thoughts to signal bodily reactions was published in the American Journal of Clinical Hypnosis.
Dr. Bennett G Braun reviewed several case studies of patients exhibiting multiple personality disorders, and reported that some personalities exhibited severe allergies, while others in the same patient do not (Braun 2011). For example,
A male multiple was allergic to citrus juices in all personalities except one. If this personality ate an orange and remained in control of the body for a sufficient period of time to digest and metabolize the orange, no ill effects would be experienced by the system. Conversely, if he switched executive control too soon, a rash which itched and blistered would often be the result. If the personality that was not allergic to citrus resumed control, the itching would cease, “. . . as if I had taken an antihistamine.” -- (Braun 2011).
The case studies reviewed in Braun's article demonstrate that immune system responses are subject to beliefs. As it turns out, so are bodily responses that relate to metabolism, healing, growth, and almost anything else the body does.
The Milkshake Study
Morozko often says "The story you tell yourself is more important than the experience you have," and a decade-old study from researchers at Yale and Arizona State Universities confirms it (Crum et al. 2011).
Researchers gave participants identical milkshakes, with different labels. The first was labeled as a high-fat, high-calorie, dessert shake made with vanilla ice cream. The second was labeled non-fat, zero-sugar, low calorie yogurt dessert substitute.
Both shakes were exactly the same and participants reported no subjective difference in their feelings of "fullness" after drinking them (as we might expect).
However, their bodies responded differently.
When participants first saw the labels, their blood serum levels of an appetite-stimulating hormone called ghrelin spiked in response to the "high calorie" label, and remained flat in response to the "low calorie".
Elevated ghrelin levels signal the body to eat more food, decrease metabolic energy expenditure, increase energy stores, resist insulin, and shift the body from fat- to glucose-burning metabolism (Müller et al. 2015). In other words, increased ghrelin is the last thing that someone trying to lose fat and build muscle wants in their bloodstream, and simply looking at the label of a dessert shake can stimulate endogenous ghrelin production.
Ghrelin has other effects inside the body, too -- like stimulating memory. If there's an evolutionary advantage to ghrelin, it may be that it prepares the body to gorge on rich foods and remember the source of those foods.
You might think that, although ghrelin levels were primed by different packaging, after the participants drank the identical shakes, their ghrelin levels would stabilize at similar levels, as their bodies responded to the biochemical signals in the shake.
That's not what happened.
When participants drank the shake labeled "high calorie," their ghrelin levels declined significantly more than when they drank the shake labeled "low calorie."
Believing that they had consumed a high-calorie drink crashed their appetite from elevated to far below the levels they experienced when they believed they had consumed a low-calorie drink. That is, the hormonal signals of appetite were satisfied by the belief that they should be satisfied, but not satisfied by a drink they believed could not satisfy their hunger -- even though the drinks were the same.
It would be no surprise if people who believe they are "dieting" remain in a constant state of ghrelin dysregulation that convinces them they are still hungry, no matter what they've eaten.
The results of the Milkshake Study are consistent with separate studies that relate mental imagery to strength gains. For example, subjects who imagine lifting heavy objects gain strength, compared with subjects who imagine lifting lighter objects (Slimani et al. 2016) -- a finding reinforced by studies that show thinking about strength training can serve as an effective partial substitute for doing strength training (e.g., Pearson 2011). what each of these studies helps us understand, is that our body composition is controlled not only by what we eat, and what we do, but how we think.
What worked for me and how I got away from it
For my part, the key to my weight loss was not my ice bath so much as it was a new food mantra. When I was about 245lb and determined to lose the excess weight, I told myself"
I eat what I want, when I want, however much I want.
If that sounds like the opposite of a diet, then that's probably because it is. I lost more than 50lb on an anti-diet.
The key for me was to decide I only wanted great food.
If it wasn't great, I didn't want it. I'd rather fast.
I skipped a lot of free faculty lunches after I decided that I didn't want to eat that garbage anymore. And when I stopped think about what I couldn't eat, and instead started thinking about the how I wanted to live my life, the pounds started coming off fast.
When I had my prostate scare, I would cycle in and out of keto, to discourage cancer growth. But I also instituted what I call "carb confusion days," when I would go to the bakery and order one of each and gorge myself on fantastic baked goods. I can only imagine the hormetic shock to my gut microbiome, the digestive inefficiencies, and whatever adaptive stress response my body underwent.
And it worked well for me.
I started getting away from my "eat great," diet as I read more books about what I should eat, and should not eat, and the reading changed my mentality from positive thoughts that were working well to negative thoughts about what I really should be doing (but wasn't).
I read about carnivore, omnivore, seed oils, fasting, grass fed, and lots of thing in social media that said I should never eat this or that our the other thing. As my thoughts and feelings about what I ate changed, so did my body.
According to an increasing body of scientific evidence, I should not be surprised.
Although often ignored, one’s mindset (thoughts, beliefs, and expectations) is a key component in various domains of health. The mere expectation to heal even in the absence of active pharmaceutical or chemical substances enhances the effect of medication; one’s interpretation of events despite their objective characteristics determines the impact of stress and illness on the body; and identifying housework as a good source of exercise can elicit corresponding physiological benefits without any changes in actual activity. Evidence continues to point to the idea that one’s state of mind influences the body, and we cannot easily separate the interdependence of mind and body. -- Crum et al. (2011).
What comes next
Last night my girlfriend and I went to a new sushi restaurant that opened in my neighborhood. It looked like a good place, inside a major hotel, and I was curious.
She hates seafood, so we skipped straight to the dessert menu. We got crème brûlée, because that's one of her favorites, and something called "honey toast" that you can probably imagine is straight-up sugar poison.
The physicians I respect would probably tell me, "Don't ever eat that!" and I would deny myself the pleasure of the experience. The problem is that whatever I ate instead, some part of me would feel like the people how ate the "low calorie" milkshake, with brains that told them they had been denied food and so they must still be hungry.
So I decided we were going to order the desserts, because maybe they would be great, and my brain would tell my body I wasn't going to need food for long while.
It turned out the crème brûlée was too runny and the honey toast was nothing great. We didn't finish them, and I didn't feel like I was missing anything.
Thought signaling
To set my brain and body back on the course that benefited me in the first place, I'm discarding all the "shoulds," and the "nevers" from my vocabulary. I'm going back to my mantra of eating what I want, doing what I want, when I want -- and reminding myself that what I want is a long, healthy, life that allows me to keep learning and teaching well past an age that most people would consider geriatric.
About the Author
Thomas P Seager, PhD is an Associate Professor in the School of Sustainable Engineering at Arizona State University. Seager co-founded the Morozko Forge ice bath company and is an expert in the use of ice baths for building metabolic and psychological resilience.