1. The Keepers and the Kept: Metabolism Cages in Racial Formations

Metabolism Cages

The mental picture of a metabolism cage should not conjure an image of a circus-like barred cage or a wild animal trap. A metabolism cage is a scientifically engineered confinement technology that captures and measures the flow of matter into and out of a confined animal’s captive body. Subject zero of metabolism cage research is the humble guinea pig whom Antoine Lavoisier, Marie-Anne Paulze Lavoisier, and Pierre Laplace placed into a rudimentary ice calorimeter in 1789.1 The team wanted to discover how much heat from the animal was required to melt a given quantity of ice; this led to a scientific revolution in our understandings of respiration as a form of metabolic combustion in nature and in animal bodies. The Lavoisiers, for their part, were caught up in a political revolution—they were beheaded in the Reign of Terror during the French Revolution.

Since 1789, dozens upon dozens of species of rodents, birds, primates, ruminants, and aquatic creatures have been kept inside metabolism cages for scientific, military, and commercial study. Mice, rats, guinea pigs, voles, squirrel, opossums, mink, hamsters, lemmings, beavers, manatees, rabbits, owls, chickens, turkeys, geese, fruit bats, lorikeets, llamas, deer, cows, yaks, goats, sheep, cats, dogs, pigs, seals, monkeys, and humans—they have all been kept inside metabolism cages. Therefore, this is not just one cage; there are hundreds of different cage designs of different sizes and capacities, each put into use in thousands of experiments designed to extract knowledge about how matter and bodies interact.

Metabolism formed as an object of biopolitical knowledge and target of institutional intervention mid- to late nineteenth century as new questions of labor, energy, and agriculture emerged under European colonialism and industrialization. The big question brought about through these relations of ruling was how to extract enough energy from nature to feed the dislocated, poor, and laboring masses in the colonies and metropoles enough to guard against revolutions and mass starvation.2 New research programs at the intersection of comparative physiology and biological chemistry brought metabolism cages to bear on these complex new world problems. Well supported research programs at the University of Munich (Justus Leibeg, Carl Voit, Max Pettenkofer, Max Rubner), at Wesleyan University (Wilbur Atwater), and the Carnegie Nutrition Laboratory at Harvard (Francis Benedict), were exported elsewhere to help establish metabolism cages as an essential experimental apparatus around the world. While their use in experiments began in continental Europe and the Americas, they became a key part of transnational scientific infrastructures and colonial development projects throughout Africa, South America, Australia, and Asia. The so-called discovery of the calorie was made possible inside nineteenth-century metabolism cages.3

As part of a long-term, global effort to gather and operationalize vast amounts of intelligence about metabolism, metabolism cages feature in range of scientific fields including agriculture, nutrition, pharmacology, veterinary medicine, dairy and animal sciences, zoology, ecology, psychology, neuroscience, nuclear and sports medicine, environmental toxicology, weapons sciences, gnotobiotics, and space experiments. Humans sent metabolism cages to space aboard SpaceLab. The diversity of forms of matter that have been placed inside metabolism cages alone or passed through animals’ bodies is all-encompassing of biotic and abiotic things. Flora, fauna, pharmaceuticals, toxins, cosmetics, ground up animal tissues, feces, TNT. If one can name a thing that might meet an animal during its life, it has likely been studied in a metabolism cage. What has come to be known in the biopharmaceutical and biochemical industries as ADME research (absorption, distribution, metabolism, excretion) must take place in metabolism cages because they are uniquely designed to capture bodies’ material outputs in gas, solid, and liquid forms for study. The observable biochemical effects of any part of a molecule—a moiety—can be isolated inside metabolism cages.

For European and American scientists, metabolism operated as a metaphorical black box, a machine that transforms inputs into outputs through unknown and/or hidden mechanisms and transformations.4 Knowing precisely what goes in and what comes out of metabolism cages tells scientists not only about the biochemical composition of the “inputs” and “outputs” but also about the bodies that process those the inputs into outputs.5 To pose new questions about the metabolism of matter in caged animals, keepers had to devise new technoscientific instruments—metabolism cages—to capture the movements of matter through different kinds of plant and animal bodies. Opening the black box of metabolism required the development of new practices of instrumentation design and the integration of theories and methods needed to effectively contain different species.6 Keeping different species in their own metabolism cages presented unique design challenges for cage designers and opened new epistemic frontiers for scientists and their institutional supporters in government and industry. Today, much of the so-named ADME research that takes place within metabolism cages today is carried out in service of commercial interests in the biochemical effects of food, drugs, and toxins. Multinational food and pharmaceutical companies have profited handsomely from the monetized knowledges that have accumulated by virtue of industrial scale animal confinement in metabolism cages.

“Respiratory calorimeters” were the first metabolism cages designed for humans in the so-called New World, along the lines of the famous apparatus that Wilbur Atwater and Edward Rosa built and operated at Wesleyan University from 1896 to 1908. With startup and operational funding from the university, local industry and private sponsors, and the United States Government, Atwater was able to maintain its expensive operational costs at $10,000 per year. Atwater and his colleagues conducted over five hundred experiments in this device; the ROI on this investment was favorable. As mentioned, this particular metabolism cage was used to establish and institutionalize the food calorie as a scientific measurement of food’s nutritive value.

Metabolism cages have been used profitably to “unlock” new knowledges about how matter and bodies interact and this new knowledge was acquired at the moral cost of mass scientific imprisonment of new world animals in metabolism cages. Despite whatever intelligence metabolism cages have delivered to science, nations, and industry, those benefits have been secured through confinement. Scientific experiments involving metabolism cages are premised on a simple carceral epistemology: a body in the cage can be known, a body in the wild cannot be known.7 The act of one person keeping another animal in a metabolism cage establishes a carceral relationship between the keeper and the kept. It is a social and historical fact that some people have kept other people and non-human animals inside metabolism cages in the name of science and technological progress. Strangely, in accepted histories of calorimetry, the practice of caging at the center of this science is framed as incidental, peripheral, or altogether unrelated to the core scientific questions and their epistemologies. This chapter puzzles over the epistemological effects of carcerality on Western metabolic knowledge, as evidenced in biomedical discourses comparing metabolism cage occupants as “free-living” or “in the wild,” which I will discuss later.

Practices of segregation and aggregation take place at three “levels” of metabolism cage research: individual, pairs and small groups, and social collectivities. The earliest metabolism cages were built for keeping only one occupant, where that one individual occupant stands in for or models its species, a population, or some other scientifically meaningful group of which it is a members. Other metabolism cages are designed for pairs or small groups of animals, who are housed together strategically, often to reduce the stress of individual captivity on specimens. Metabolism cage designs can be institutionalized into the material infrastructure of social institutions and their pecuniary focus on the effects and distribution of food and drugs in prisons, labor camps, schools, and hospitals. Importantly, the intelligence derived from metabolism cage experiments involving humans was presumed to be universally applicable to all human beings—so-called “Man”—but that knowledge often had to be interpreted in terms of other social hierarchies linked to labor, race, gender, and age. Over time, ideas have changed about which species and persons should be kept in metabolism cages and what is to be learned from their confinement. Historically, the keepers have tended to be white male scientists with ties to state and industrial power. That hasn’t changed much.

Historians of human and animal calorimetry have identified occupation, age, and gender as important social characteristics that metabolism cage researchers considered when calculating human energy needs, recruiting subjects, and securing funding for their work.8 Within these histories, race is conspicuously absent from historical accounts of the scientific, design, and biomedical labor of human calorimetry, despite the emergence and persistence of extreme racial and ethnic inequalities in chronic metabolic disorders over the course of the twentieth century.9 For humans, the most advanced metabolism cages for humans used today are mobile metabolic carts in intensive care units, metabolic rooms used in clinical research facilities, and portable calorimeters like Lumen, which are used by monied and metabolically curious Western consumers. These metabolism cages are experimental sites for the clinically consequential and highly controversial study of racial group differences in human metabolism. Articles, commentaries, and editorials in contemporary biomedical journals have been calling for the practice of race correction of the clinically significant biomarker: resting metabolic rate (RMR).10 RMR refers to the amount of energy a body uses when it is “at rest”—awake, not eating, and not being active/exercising. Several widely used predictive equations such as Harris-Benedict (1918), Cunningham (1980), and Mifflin-St. Joer (1985) have been found to overestimate RMR in Black populations by up to three hundred calories per day, a miscalculation that leads to overfeeding critically ill patients in intensive care units. Human metabolism cages have helped identify these racially unequal mathematical practices in RMR estimation by cross validation—whole-body calorimeters are designed just for this purpose. I am curious how these calls are linked to the deeper social history of metabolism cages as sites for the production of scientific ideas about race and racial difference.

To make sense of this putatively racial cage, I develop a biohumanities framework in this chapter, pairing social histories of racialized scientific labor and biocapital exchanged in human metabolism cage research with a political analysis of who benefits from metabolism cage experiments. I open with the empirical question: Are metabolism cages sites of racial formation?11 I hope to add to the very limited scholarship that is explicitly focused on the emergence of animal and human calorimetry and racial science.12 To trace patterns of racial formation, I compare the racial (and often explicitly intersectional) discourses that keepers use to justify the patterns of racial inclusion and exclusion in metabolism cage research and to explain and interpret their scientific findings. I speculate that metabolism cages operate as racial cages because (a) they are experimental spaces where conceptual ideas about race, human difference, and social inequality are forged and tested through scientific experiments and biomedical surveillance; (b) they are commercial sites for the development of new technologies of economic exploitation, social stratification, and unequally distributed environmental harms; and (c) they are real dramaturgical sites where who gets to perform the role of keeper and who must play the role of the kept is structured by racial, gender, class, and species hierarchies.

The chapter continues with a short story about Emil Osterberg, a Swedish-born custodian/scholar and known drinker, who was the first human to spend time in Wilbur Atwater’s respiration calorimeter at Wesleyan University in the winter of 1896. Perhaps it was his “Swedish-ness” that made him the ideal human subject zero for a metabolism cage. The second part of the chapter unfolds in the 1930s and tells the story of Jim—a Black man who worked as a “professional guinea pig” in William Abbott’s research program at the University of Pennsylvania School of Medicine—and a bullet that was lodged in his body. Abbott was familiar enough with metabolism cages to joke about keeping Jim in one to get that bullet. These events surround the development of the Abbott-Miller Tube and highlight the evolving bioethics of race, gender, and class in experiments on commercially viable medical technologies linked to metabolism. The final section of the chapter addresses how historical practices of race correction shape contemporary inequalities in calorimetry, comparing differential access to high-tech metabolic cages and metabolic carts used in intensive care units and practices of race correction in the estimation of the resting metabolic rate.

A Sojourn in the Chamber

On February 17, 1896, Emil Osterberg, then a twenty-nine-year-old Swedish-born immigrant who worked as “a general assistant” for chemist Wilbur Atwater at Wesleyan University, became the first human being in the United States to voluntarily enter a human-sized metabolism cage. Osterberg became an assistant to Atwater, but his main gig was laboring as the custodian of Orange Judd Hall, where the device was located. Atwater and his colleague, Edward Rosa, built the apparatus they called a respiratory calorimeter, the first airtight metabolism cage built to hold one human at a time, and in its experiments, produced a wealth of knowledge about the food calorie and the biochemical substrates of human metabolism.

Emil’s first experiment was in February 1896, but Atwater later enlisted him to participate in controversial alcohol experiments he conducted in the cage because “since boyhood, [Emil] was accustomed to the moderate use of alcoholic beverages.”13 Historians often elide Emil’s first name for the substitution of his nationality (Bill Bryson called him “Swede Osterberg”14 or Edward Kirkland who only offers his initial “E”15). In his write-ups of experiments, Atwater often took care to describe the nativity of his experimental subjects in terms of national or regional identities. Osterberg was “A Swede, by birth,” Mr. A. W. Smith was “Canadian, by birth” and Dr. O. F. Tower was “a native of New England.”16 Osterberg participated in several cage experiments and even became a published author in the American Journal of Physiology. In 1900, he coauthored a paper with Francis Benedict (who went on to run the Carnegie Nutrition Laboratory that reported the results of their study placing human fat tissues biopsied from cadavers at the Connecticut Hospital for the Insane in Middletown into Atwater’s smaller bomb calorimeter—“The Elementary Composition and Heat of Combustion of Human Fat.”)17 Perhaps Emil entered the cage a janitor and, through trials and tribulations, emerged a little-known scholar.

As human subject zero (in the U.S. context), Emil represented an ideal-type research subject for early human calorimeter researchers. Based on archival analysis, Elizabeth Neswald argues that the ideal subject for such studies was male, responsible, intelligent, and generally interested in the research; these qualities were needed to facilitate the research and endure the psychological pressures of being caged.18 Only other Wesleyan-affiliated white male scientists and students participated in cage experiments during its twelve-year run in twenty-two or twenty-three experiments; I don’t know how many Emil participated in. According to Kirkland, publishing magnate William Randolph Hearst once sent an unnamed “lady reporter” to visit Atwater, demanding to spend time in the cage; Atwater was not happy with the stunt and did not allow it.19

Neswald’s STS-inspired analysis raises questions about subjects’ agency in human calorimeter research, framing the dynamic as one of resistance and cooperation, borrowing from Andrew Pickering’s language.20 Reading the brief published account of Emil’s experience in the first experiment here, you can get a sense of Emil’s apprehension and Wilbur’s minimization of the “nervousness” of being sealed up in a cage. Also noteworthy are the elements of Emil’s occupation, eating practices, and literacy that frame his participation.

Respiration Experiment No. 1 (Digestion Experiment No. 11): The subject in this experiment was a Swede of 29 years of age who acted as a laboratory janitor and was accustomed to a moderate amount of muscular work. He would be called a hearty eater. During the progress of the experiments, he read a little for diversion, but the larger part of the time was as free from mental and physical activities as practicable. While he was entirely willing to do everything that was asked of him, it became evident that he did not find the sojourn in the chamber entirely agreeable. Toward the end of the second experiment he became somewhat ill, but the circumstances were such that it could hardly be attributed to any impure air or any other abnormal condition; indeed, there seemed to be good ground to believe that the slight illness was caused by nervousness due to the sojourn in the respiration chamber and an undefined and unfounded fear that some trouble might result.21

Emil worked in Judd Hall and did not sign up for this. According to this account, he did not have a good experience during his captivity in the chamber; “he did not find the sojourn in the chamber entirely agreeable,” and by the end of his second experiment “he became somewhat ill.” Clearly, he was willing to go in there but he freaked out. Maybe he gasped for air. What did it sound like in the chamber, as the gas pipes hissed and the light closed in around the singular window looking out into the basement? The scientific and economic promise in the device was too great for Atwater to be concerned with “undefined and unfounded fears” of being kept.

Jim’s Bullet and the “Striking Blackamoors”

Jim was a Philadelphia-area Black man who became involved in the research program of William Osler Abbott, a gastroenterologist who arrived at the University of Pennsylvania School of Medicine in 1930–31, joining the research lab of Dr. T. Grier Miller. Having been trained in the nascent fields of pharmacology and physiology, Abbott’s specific interest in gastroenterology was developing new devices and techniques to deliver drugs into the body. In Dr. Miller’s words, Abbott “wished to carry over to human beings [from other species] certain experiments on the motor effects of various drugs on the duodenum.”22 Over a twelve-year period, Abbott conducted five hundred intestinal intubation experiments including tests on himself, as was common practice at the time among research physicians.

In 1957, the austere outlet Transactions of the American Clinical and Climatological Association published a speech Abbott delivered in 1939 before The Charaka Club, a group of doctors who shared an interest in literature, in a dark world cast of medical humanities.23 Titled “The Problem of the Professional Guinea Pig,” Abbott’s speech describes his ethically fraught and logistically troubled efforts going back to 1931 and over the course of the Great Depression to manage a pool of human recruits in his experiments of a rapid mouth-to-anus gastrointestinal tube and its accompanying techniques. In Abbott’s view, the people whom he experiments upon are the “professional guinea pigs” who take the job because it pays during a time when little else does. Pay could be upward of two dollars a day (about thirty-eight in today’s dollars).

Jim, along with a small group of Philadelphia-area Black men, was a professional guinea pig in several of Abbott’s studies, which often involved subjects swallowing rubber tubing up to twelve feet in length and repeated x-ray exposures. During a Black-men-only phase of his research program, Abbott jokes that there were “mishaps.” One such event revolved around an anecdote he narrates about Jim:

I once attempted to manipulate a tube quickly into Jim’s duodenum by fluoroscopic guidance when my eyes were not well accommodated. After a good deal of vigorous palpation, I suddenly realized that the metal tip which I had been struggling to direct was behind Jim’s spinal column. A cold rivulet of perspiration trickled down my own spine. Then my eyes, by that time used to the dim light, detected an unfamiliar contour to the “bucket” and it dawned on me that what I had been trying to manipulate with notably small success was a .38 calibre revolver bullet in his erector spinae muscles. When confronted with the evidence, Jim grinned sheepishly and admitted that he’d made a grave error the night before. He had called on his sweetheart unaware of the fact that she had seen him that very evening with another girl. Such events led me to wish at times that I could keep my animals in metabolism cages.24

Historians of medicine are also familiar with Abbott’s discourse and have interpreted this last sentence as evidence of Abbott’s use of violent and exploitative rhetoric and cultural racism given how he animalized Black men to justify an ethically fraught research program.25 In my reading, the only reason why he would joke that he wanted to keep his animals (like Jim) in metabolism cages would be to avoid having to go through Jim’s feces by hand later to fish the bullet out himself. I think what Abbott really wanted was a keepsake.

Abbott’s positions on the animality of blackness in the context of metabolism cage research make sense given his broader views about animals and humans in medical experimentations. Abbott’s use of animalizing discourse is evidenced throughout the speech, along with glib efforts at humor, a boring doctor’s wit, and self-serving social commentary. As you can read here in the opening paragraph, “It is then to the problem of the capture, selection, care, and training of good, healthy human guinea pigs, if I may use a trite phrase, that I would invite your attention.” Another example: “We had a metaphorical can opener but no beef, and beef we were determined to have.”26 In this couplet, the tube device is the can opener and the human subjects are the “beef.” Abbott’s view was that a wide variety of humans should work as professional guinea pigs because “If the proper study of mankind is man, then there can be but one really satisfactory experimental animal.”27 Yet, he also discusses the scientific rationale and practical exigencies of studying different species for different reasons, partly due to the specificities of the question at hand: “In this way, a student can study the effect of the procedure on the animal that really matters.”28 If the question is about humans, study humans. If the question is about dogs, study dogs.

Upon the suggestion of his secretary, Abbott enlists his Black custodian (yes, another custodian), Harry, to help him recruit a group of Black men (“apparently sober and in a state of fasting at 8:30 am”) for the studies, which he does. Flip, Sam, Dan, Slim, Dan, and unnamed others appear. Abbott recounts one occasion when the group collectively refused to show up for a scheduled public intubation at the American Medical Association unless Abbott doubled their pay, which was currently $1.50 per hour. Using the racial epithet “blackamoors” to describe this group, Abbott recounts their collective labor action against him and how he managed it:

Had I been an older hand at the role of captain of industry, I would have foreseen it, but as it was, I had no inkling of what was brewing until a certain day less than a week before the convention when the whole crowd went on strike together. Double the pay or no demonstration was the demand. That was a bad few minutes for me. No dogs, cats, rats or rabbits that I had ever handled had done this, but there was one opening left. It was then 1:30 P.M. At 2:00 the last examination of the spring term, third year obstetrics, was due to begin. I left the black delegation sitting and sprinted for the Medical School. As the students gathered, I gave them an impassioned appeal for volunteers, offered the pay of my striking blackamoors, and in five minutes a shipment of scab labor had signed up, that would have made any factory foreman green with envy. Thereupon I returned to the committee, and, the National Labor Relations Board being as yet unborn, I had the pleasure of indulging in a little old-fashioned capitalism. We fired the whole lot of them, lock, stock and barrel. The exhibit went off like clockwork. The volunteers from the third year class stood up to those tubes like veterans of the line.29

In addition to remarking on the need to expand the experiments conducted on people living in asylums and prisons, upon his wife’s suggestion Abbott started recruiting in the local papers, drawing in the city’s poor and working-class people, including many women, into his research program. For Abbott, within each respective species there is an identifiable segment of the population that is more amenable to experimentation given variations in “temperament,” which is “governed by a set of natural laws which are fairly universal.” Differences in temperament generate two groups: the ones that fight and refuse and what he calls “the ones that stick.” He explains the difference in a direct comparison between dog and human recruits:

Were one doing a chronic experiment on a dog, say a long-time absorption problem with a Thirey fistula, he would not go to the animal house and pick a wiry young bull pup with hair-trigger nervous system and a desire to fight everything in sight. Obviously, one would pick a big, lazy, overweight bitch that could be counted upon to lie and wag her tail while being worked over, and, interestingly enough, it is always to the human counterpart of this animal that my clientele dwindles down. Each year the lean ones seem to have strayed away from me, the younger ones have better jobs and the newlyweds are having another baby or have moved away, but the easy-going hundred forty-pounders with a streak of gray beginning to show, bring their knitting and their children’s photographs and pair off in congenial couples so they can gossip the tedium as the tubes go down. They are the ones that stick.30

For Abbott, the best experimental subject was one whose body is inured to the violence of fatness, laziness, debauchery, complacency—all cultural stereotypes about Black, poor, and working-class people in Depression-era Philadelphia.

Miller and Abbott would go on to coinvent the Miller-Abbott Tube in 1939, a double-lumen rubber tube featuring an opening to the stomach for suction, another opening to the jejunum for feeding, and on the other end a small balloon filled with mercury (to aid gravity in passing the tube). Until 1978, the Miller-Abbott Tube was widely used to intubate the gastrointestinal tract and break obstructions, deliver drugs and enteral nutrition beyond the stomach. It fell out of use due to complications with the mercury and the emergence of superior designs.31 Still, Abbott made “contributions” to enteral medicine, involving serious medical situations in which knowing precisely how much food to push into a body means life or death.

Race Correction in Calorimetry

Critically ill, immobilized, and unconscious human bodies still must receive calories (and other nutrients) from food, even if they are unable to chew or swallow raw or prepared foods. Guided by legal standards of care and financial arrangements, medical providers and pharmacists administer nutrition enterally, or via tubes, to patients in wide variety of precarious medical situations.32 This branch of clinical nutrition is called enteral nutrition. Standard histories of tube feeding in medicine often minimize this practice, which is genealogically linked to the punitive practice of force-feeding feminist revolutionaries, prisoners, and asylum residents. Enteral feeding is difficult to get right, is painful, and can lead to its own medical complications. Comparative outcome research conducted demonstrates that underfeeding and overfeeding people in these situations can be harmful to an already traumatized and recovering body. Additionally, the kinds of traumas that befall a critically ill patient have direct and observable metabolic consequences on their own, effects that medical providers must account for when providing emergency care. So, how do doctors figure out what and how much to feed immobilized human bodies while avoiding consequences and improving critical care outcomes for these patients? The answer has to do with calculating precisely how much energy is required for that body to function when it is at rest (this is called the resting metabolic rate, or RMR), while accounting for other situational factors.

In practice, there are two ways to calculate RMR. The first and best approach, considered the gold standard, involves keeping a patient’s body within one of two types of contemporary metabolism cages: a metabolic room or a portable metabolic cart, both of which allow clinicians to indirectly calculate the RMR.33 Metabolic carts and metabolic rooms are used in clinical research facilities and intensive care units (ICUs) and are high-tech descendants of Atwater’s late Victorian respiratory calorimeter. Strangely, these are metabolism cages a person might want to be kept in for a brief period, should they be in the unfortunate situation where they cannot take food by mouth, so that medical providers can get the numbers right. The number of large, whole-body human calorimeters that have been built around the world is somewhere north of three dozen while the number in full operation today is smaller and clustered in the Global North (especially in the United States and Europe). Metabolism cages are expensive pieces of technical equipment that have sited significant biomedical and environmental research. Especially since the 1980s, this research has been justified within a health inequalities frame, recruiting the kept based on their membership in social groups experiencing health disparities.

The second approach is exclusively mathematical in which the patient’s anthropometric characteristics are entered into an algorithm or equation that estimates resting metabolic rate (RMR) in comparison to population-level parameters. Unfortunately, the numeral standards for human RMR were established in 1915 in exclusively white and presumed homogeneous reference populations.34 Analysts are calling for RMR estimations to undergo some form of “race correction” that accounts for the assumption of racial differences in RMR. This is different from the eGFR case of race correction as articulated by Lundy Braun and Dorothy Roberts because, unlike that case in which race is explicitly included, “race is not considered in formulas used to determine caloric requirements in clinical practice.”35

In Nutrition & Diabetes, researchers ask, “Do We Need Race-Specific Resting Metabolic Rate Equations?”36 This question is raised in a context where Black patients do not have equal access to the best enteral nutrition across the life course including Black infants, children, and adults in critical care situations and Black elders in end-of-life scenarios where feeding tubes are often used to provide nutritional and pain support.37 Given these racial inequalities, how do the mathematical versus technological measurements of RMR compare in terms of how intersectional inequalities are surveilled, represented, and explained? Should race be considered in RMR estimations and if so, how?

In the 1990s and 2000s, several studies observed race and gender differences in RMR as measured via indirect calorimetry in metabolism cages.38 During this period, researchers posited genetic theories to explain these social differences, featuring comparisons of ancestral informative markers (AIM) and measurements of racial admixture.39 Researchers also offered physiological explanations for African Americans’ comparatively lower RMR compared to Whites: RMR is related to European ancestry via selective pressures on mitochondria that advantaged populations who lived in “higher latitudes”40 and RMR is lower in African Americans because of group differences in the fractional mass of high metabolic rate organs (e.g., brain, liver, kidney).41 Within this logic of scientific racism, Gower and Fowler argue that “race can be deconstructed into physiologic variables that explain free-living gain in body fat” based upon the presumption that all Black people have “inherently high AIRg (Acute Insulin Response to glucose).”42

Questions of how the variables of race and gender effect differential outcomes frame the overarching research program, leading to sampling frameworks that specifically feature enough Black men and women to permit statistical comparisons to white men and women. In this period, analysts focused on explaining high rates of obesity and susceptibility among Black girls, adult premenopausal and overweight Black women, and older “free-living” Black women.43 Any racial and/or ethnic differences that were identified in a sample could not be interpreted independently from gender. Carpenter and colleagues proclaimed to be the first group to examine “the effects of race on daily energy expenditure in free-living African Americans,” drawing a clear distinction with research that takes place inside an unfree experimental place like a metabolism cage.

Among the sites where such comparative racial research has taken place is within the Clinical Diabetes and Nutrition Section at the U.S. National Institutes of Health complex in Phoenix, Arizona in the 1980–1985 period, led by Eric Ravussin.44 This facility featured a then-state-of-the-art respiratory chamber modeled after one built at the University of Lausanne in Switzerland in the 1970s, where Ravussin earned his PhD in human physiology. In justifying their approach to using indirect calorimetry via this particular metabolism cage to study Black women’s propensity for obesity, Weyer and colleagues argued that the prior studies showing Black women to have a lower resting metabolic rate than white women were flawed because they were not conducted over a long enough period of time and they were conducted using “ventilated-hood systems.”45 In contrast to what was known about Black women, “little is known about energy metabolism in African American men,” they assert. To study these (intersectional) dynamics, their objective was to compare twenty-four-hour measurements of energy metabolism between African American and white women and men using a respiratory chamber. They found “ethnic differences” in sleeping metabolic rate (SMR), twenty-four-hour respiratory quotient (24RQ), and fat-free mass (single best determinant of energy expenditure). The “ethnic differences in energy metabolism seem to be sex specific, i.e., energy expenditure was lower particularly in African American women, whereas in men, the major ethnic difference was in substrate oxidation.”46 They also found ethnic differences in body fat distribution and body composition as measured by fat-free mass, which Weyer and colleagues describe as “the single best determinant of energy expenditure in humans.”

Importantly, Eric Ravussin and his colleagues took up the question of how the knowledge derived from studies of human metabolism that take place in the cage relates to knowledge derived from studies that take place among “free, living” individuals.47 One of the big differences between being in a cage and not is the movement of the body in space, what the researchers refer to as “spontaneous physical activity” or SPA. Snitker and colleagues studied this question in fifty nondiabetic Pima Indians, who completed a twenty-four-hour stay in the Arizona respiratory chamber followed by a seven-day follow-up of “free-living” using the doubly labeled water method of indirect calorimetry, which involves “enriching the body water of a subject with heavy oxygen and heavy hydrogen and then determining the difference in washout kinetics between both isotopes.”48 The doubly labeled water method “has proved an ideal technique for the estimation of ‘field’ metabolic rate in free-living animals and birds.”49 This technique, first developed by Lifson and McClintock, which does not require caging, has been widely adopted to study energy needs in free-living animals.50

The Keepers and the Kept

Who benefits from metabolism cage research? The keepers or the kept? Much of what is known about metabolism was studied under experimental conditions involving multispecies confinement in metabolism cages; this knowledge has been used to engineer new genres of foods, drugs, toxins, and weapons. This account of the racialized scientific labor involved in conducing metabolism cage research and analysis of the multiple forms of biocapital exchanged in that research both point to complex racial meanings and social structures that are linked to the production of knowledge about race and animal metabolism. In this way, metabolism cages are an example of what Thomas Gieryn calls a truth spot where how we know what we know about animal metabolism is sanctioned, encultured, and instrumentalized to build an industrialized and carceral form of metabolism.51 In order for the metabolism cage as truth spot to function properly, a political drama must play out; somebody must play the role of the keeper and somebody else has to be kept.

This carceral relationship between the keepers and the kept maps onto a scientific relationship between scientist experimenters and their specimen(s). Dr. Abbott plays the keeper and Jim, one of his animals, gets inside the cage so Abbott doesn’t have to go through his feces by hand. Dr. Atwater plays the keeper and Emil, his building’s janitor, gets inside the cage and takes a drink to calm his fears of captivity and suffocation. Dr. Ravussin plays the keeper and his racialized patients with serious metabolic disorders get inside the cage so that scientists can evidence claims about asocial biological differences within a broader discourse about the universal human. Identifying, assembling, and evaluating evidence about the historical, multinational, and multisector costs and benefits of metabolism cage research is a daunting empirical task given the industrial scale of the enterprise. Any analysis of who benefits from this form of mass scientific imprisonment and data extraction that does not take carcerality itself or racism into account is limited by virtue of its attempted separation of the biological and the human.

Notes

1. 1. Ashworth E. Underwood, “Lavoisier and the History of Respiration,” Proceedings of the Royal Society of Medicine 37, no. 6 (1944): 247–62.

2. 2. Sheila Jasanoff, “Biotechnology and Empire: The Global Power of Seeds and Science,” Osiris 21, no. 1 (2006): 273–92.

3. 3. Jane Dixon, “From the Imperial to the Empty Calorie: How Nutrition Relations Underpin Food Regime Transitions,” Agriculture and Human Values 26, no. 4 (2009): 321–33.

4. 4. Bruno Latour, Pandora’s Hope: Essays on the Reality of Science Studies (Harvard University Press, 1999).

5. 5. Frederic L. Holmes, “The Intake-Output Method of Quantification in Physiology,” Historical Studies in the Physical and Biological Sciences 17, no. 2 (1987): 235–70.

6. 6. J. A. McLean and Graham Tobin, Animal and Human Calorimetry (Cambridge University Press, 2007); Paul Webb, Human Calorimeters (Praeger, 1985).

7. 7. M. J. Dauncey, “Whole-Body Calorimetry in Man and Animals,” Thermochimica Acta 193 (1991): 1–40.

8. 8. Elizabeth Neswald, “Food Fights: Human Experiments in Late Nineteenth-Century Nutrition Physiology,” 95:170–93. Clio Medica (Brill, 2016).

9. 9. James Doucet-Battle, Sweetness in the Blood: Race, Risk, and Type 2 Diabetes (University of Minnesota Press, 2021); Anthony Ryan Hatch, Blood Sugar: Racial Pharmacology and Food Justice in Black America (University of Minnesota Press, 2016); Michael Montoya, Making the Mexican Diabetic: Race, Science, and the Genetics of Inequality (University of California Press, 2011); Amy Moran-Thomas, Traveling with Sugar: Chronicles of a Global Epidemic (University of California Press, 2019).

10. 10. Crystal C. Douglas et al., “Ability of the Harris-Benedict Formula to Predict Energy Requirements Differs with Weight History and Ethnicity,” Nutrition Research 27, no. 4 (2007): 194–99; David Frankenfield et al., “Comparison of Predictive Equations for Resting Metabolic Rate in Healthy Nonobese and Obese Adults: A Systematic Review,” Journal of the American Dietetic Association 105, no. 5 (2005): 775–89; B. A. Gower and L. A. Fowler, “Obesity in African-Americans: The Role of Physiology,” Journal of Internal Medicine 288, no. 3 (2020): 295–304; James Reneau et al., “Do We Need Race-Specific Resting Metabolic Rate Prediction Equations?” Nutrition & Diabetes 9, no. 1 (2019): 21; Teresa A. Sharp et al., “Differences in Resting Metabolic Rate Between White and African-American Young Adults,” Obesity Research 10, no. 8 (2002): 726–32; Christian Weyer et al., “Energy Metabolism in African Americans: Potential Risk Factors for Obesity,” The American Journal of Clinical Nutrition 70, no. 1 (1999): 13–20.

11. 11. Michael Omi and Howard Winant, Racial formation in the United States (Routledge, 2014).

12. 12. Warwick Anderson, The Cultivation of Whiteness: Science, Health, and Racial Destiny in Australia (Duke University Press, 2006).

13. 13. Wilbur O. Atwater, Experiments on the Metabolism of Matter and Energy in the Human Body, 1898–1900 United States. Office of Experiment Stations. Bulletin; 109 (Government Printing Office, 1902), 2.

14. 14. Bill Bryson, The Body: A Guide for Occupants. First United States edition (Doubleday, 2019).

15. 15. Edward C. Kirkland, “‘Scientific Eating’: New Englanders Prepare and Promote a Reform, 1873–1907,” Proceedings of the Massachusetts Historical Society 86 (1974): 28–52.

16. 16. Atwater, Experiments, 239–40.

17. 17. Francis Gano Benedict and Emil Osterberg, “The Elementary Composition and Heat of Combustion of Human Fat,” American Journal of Physiology-Legacy Content 4, no. 2 (1900): 69–76.

18. 18. “Food Fights: Human Experiments in Late Nineteenth-Century Nutrition Physiology,” 95:170–93. Clio Medica (Brill, 2016).

19. 19. Kirkland, “‘Scientific Eating,’” 40.

20. 20. Andrew Pickering, The Mangle of Practice: Time, Agency, and Science (University of Chicago Press, 1995).

21. 21. Wilbur O. Atwater et al., Report of Preliminary Investigations on the Metabolism of Nitrogen and Carbon in the Human Organism: With a Respiration Calorimeter of Special Construction. United States. Office of Experiment Stations. Bulletin No. 44. (Government Printing Office, 1897), 40.

22. 22. Grier T. Miller, “Development of the Double-Lumened Tube for Intestinal Intubation,” Journal of the American Medical Association 140, no. 2 (May 1949): 147–49, 147.

23. 23. Osler W. Abbott, “The Problem of the Professional Guinea Pig,” Transactions of the American Clinical and Climatological Association 68 (1957): 1–9.

24. 24. Abbott, “The Problem,” 3–4.

25. 25. Susan E. Lederer, Subjected to Science: Human Experimentation in America before the Second World War (Johns Hopkins University Press, 1995); Harriet A. Washington, Medical Apartheid: The Dark History of Medical Experimentation on Black Americans from Colonial Times to the Present, 1st ed. (Doubleday, 2006); T. G. Schnabel Jr., “William Osler Abbott: His Double Lumen Tube,” Transactions of the American Clinical and Climatological Association 112 (2001): 50–60.

26. 26. Abbott, “The Problem,” 2.

27. 27. Abbott, 1.

28. 28. Abbott, 8.

29. 29. Abbott, 4.

30. 30. Abbott, 8.

31. 31. Laura Harkness, “The History of Enteral Nutrition Therapy: From Raw Eggs and Nasal Tubes to Purified Amino Acids and Early Postoperative Jejunal Delivery,” Journal of the American Dietetic Association 102, no. 3 (2002): 399–404.

32. 32. Elaine J. Amella et al., “Tube Feeding: Prolonging Life or Death in Vulnerable Populations?” Mortality 10, no. 1 (2005): 69–81.

33. 33. H. Mtaweh et al., “Indirect Calorimetry: History, Technology, and Application,” Frontiers in Pediatrics 6, no. 257 (n.d.).

34. 34. Frank C. Gephart and Eugene F. DuBois, “Fourth Paper: The Determination of the Basal Metabolism of Normal Men and the Effect of Food,” Archives of Internal Medicine 15, no. 5 (1915): 835–67.

35. 35. James Reneau et al., “Do We Need Race-Specific Resting Metabolic Rate Prediction Equations?” Nutrition & Diabetes 9, no. 1 (2019): 5.

36. 36. Reneau et al., “Do We Need,” 21.

37. 37. Ayham Khrais et al., “Trends Regarding Racial Disparities Among Malnourished Patients with Percutaneous Endoscopic Gastrostomy (PEG) Tubes,” Cureus 14, no. 11 (2022): e31781; Howard B. Degenholtz et al., “Race and the Intensive Care Unit: Disparities and Preferences for End-of-Life Care,” Critical Care Medicine 31, no. 5 (2003): S373; Nan Tracy Zheng et al., “Racial Disparities in In-Hospital Death and Hospice Use Among Nursing Home Residents at the End-of-Life,” Medical Care 49, no. 11 (2011): 992–98.

38. 38. Dympna Gallagher et al., “Small Organs with a High Metabolic Rate Explain Lower Resting Energy Expenditure in African American than in White Adults,” The American Journal of Clinical Nutrition 83, no. 5 (2006): 1062–67; T. M. Manini et al., “European Ancestry and Resting Metabolic Rate in Older African Americans,” European Journal of Clinical Nutrition 65, no. 6 (2011): 663–67; Christian Weyer et al., “Energy Metabolism in African Americans: Potential Risk Factors for Obesity,” The American Journal of Clinical Nutrition 70, no. 1 (1999): 13–20.

39. 39. Jose R. Fernandez et al., “Association of African Genetic Admixture with Resting Metabolic Rate and Obesity Among Women,” Obesity Research 11, no. 7 (2003): 904–11.

40. 40. Manini et al., “European Ancestry.”

41. 41. Gallagher et al., “Small Organs”; Fahad Javed et al., “Brain and High Metabolic Rate Organ Mass: Contributions to Resting Energy Expenditure Beyond Fat-Free Mass,” The American Journal of Clinical Nutrition 91, no. 4 (2010): 907–12.

42. 42. B. A. Gower, and L. A. Fowler, “Obesity in African-Americans: The Role of Physiology,” Journal of Internal Medicine 288, no. 3 (2020): 295–304.

43. 43. Jeanine B. Albu et al., “Visceral Fat and Race-Dependent Health Risks in Obese Nondiabetic Premenopausal Women,” Diabetes 46, no. 3 (1997): 456–62; William H. Carpenter et al., “Total Daily Energy Expenditure in Free-Living Older African-Americans and Caucasians,” American Journal of Physiology-Endocrinology and Metabolism 274, no. 1 (1998): E96–101; Susan Zelitch Yanovski et al., “Resting Metabolic Rate in African-American and Caucasian Girls,” Obesity Research 5, no. 4 (1997): 321–25.

44. 44. E. Ravussin et al., “Determinants of 24-Hour Energy Expenditure in Man. Methods and Results Using a Respiratory Chamber,” Journal of Clinical Investigation 78, no. 6 (1986): 1568–78.

45. 45. Weyer et al., “Energy Metabolism,” 16.

46. 46. Weyer et al., 16.

47. 47. S. Snitker et al., “Spontaneous Physical Activity in a Respiratory Chamber Is Correlated to Habitual Physical Activity,” International Journal of Obesity 25, no. 10 (2001): 1481–86.

48. 48. Klaas R. Westerterp, “Doubly Labelled Water Assessment of Energy Expenditure: Principle, Practice, and Promise,” European Journal of Applied Physiology 117, no. 7 (2017): 1277–85, 1279.

49. 49. Dauncey, “Whole-Body Calorimetry,” 10.

50. 50. N. Lifson and Ruth McClintock, “Theory of Use of the Turnover Rates of Body Water for Measuring Energy and Material Balance,” Journal of Theoretical Biology 12, no. 1 (1966): 46–74; International Atomic Energy Agency, Assessment of Body Composition and Total Energy Expenditure in Humans Using Stable Isotope Techniques (International Atomic Energy Agency, 2009).

51. 51. Thomas F. Gieryn, Truth-Spots: How Places Make People Believe (University of Chicago Press, 2019).