40 Years of Government Nutrition Data May Be Flawed
Americans severely under-report how much food they eat, and this has affected decades of nutrition data.
For forty years, the CDC's National Health and Nutrition Examination Survey (NHANES) has collected data on the caloric intake of Americans, answering the simple and important question of how much food we eat. This research has in turn been used to instruct public health policy. NHANES is actually the basis for national standards of height, weight, and blood pressure, and its findings are often used to develop programs in the public battle against obesity.
But there's just one "tiny" problem. According to an analysis conducted by exercise scientist Edward Archer at the University of South Carolina, NHANES is very likely invalid. And it's for a simple reason that almost anybody could point out: All of the data it collects on caloric intake is self-reported.
Try to remember precisely what you ate over the past twenty-four hours and you'll see why this is a problem. People aren't only inept at estimating how many calories are in the foods they eat, they're also bad at recalling what they consumed and when.
With this in mind, Archer performed calculations merely to gauge if NHANES' data is physiologically plausible. In 1991, a team of physiologists determined that average, free-living individuals must consume at minimum at least 35% more calories than their basal metabolic rate (BMR) -- the amount of calories they expend resting -- in order to maintain their weight and health. This accounts for the energy people need to perform everyday activities, from just walking around, to playing sports, to gardening, etc. Archer used a well-established equation to estimate the BMR of individuals in the NHANES study, multiplied those values by 1.35, and compared them to the self-reported energy intakes in NHANES. What did that comparison yield? The majority of respondents, totaling 28,993 men and 34,369 women, reported eating less calories than even the bare minimum necessary to survive!
Judging by how much Americans' waistlines have been infamously expanding, the respondents' eating estimations are obviously wrong. To Archer, it reinforces what previous research has clearly shown: Americans severely under-report how much food they eat, and this has affected decades of nutrition data.
As Archer told me, one possible fix is to replace self-reporting with more empirical methods of determining caloric intake. The doubly labeled water technique, which uses well-established knowledge of carbon dioxide metabolism to calculate how much energy living subjects expend, could be adapted for use in NHANES and other federally funded health studies, he says. Doubly labeled water is considered a key biomarker for long-term energy intake.
Archer, a former college football and professional polo player, exudes enthusiasm. He believes that science can truly help people live healthy and productive lives, but is dismayed that public health research consistently relies on imprecise methodology. Determined to change that, Archer hopes that his current study will impress upon people that the status quo of self-reporting isn't working.
"The nation's major surveillance tool for studying the relationships between nutrition and health is not valid. It is time to stop spending tens of millions of health research dollars collecting invalid data and find more accurate measures," he said.
Though the study was just published to PLoS ONE on Wednesday, Archer is already receiving flack. Some dissenters question his calculations, which certainly aren't completely precise considering he obviously couldn't measure each subject's metabolism or energy intake. Others insist that self-reporting is simply the only viable option. Critics also point to the fact that his research is funded by Coca-Cola, a fact I queried him about. Archer explained that it's an unrestricted research grant. In other words, the soft drink maker contractually has no input or say in what he researches or publishes.
But more important than the specifics of Archer's study is the message it shouts. Self-reports of personal health and food intake are utterly inaccurate, and if we are ever to get a clear picture of the obesity epidemic and how to solve it, we need to start by collecting credible data.
Source: Archer E, Hand GA, Blair SN (2013) Validity of U.S. Nutritional Surveillance: National Health and Nutrition Examination Survey Caloric Energy Intake Data, 1971-2010. PLoS ONE 8(10): e76632. doi:10.1371/journal.pone.0076632
(Image: Scale & Tape Measure via Shutterstock)
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Here's the first evidence to challenge the "fastest sperm" narrative.
Experts argue the jaws of an ancient European ape reveal a key human ancestor.
- The jaw bones of an 8-million-year-old ape were discovered at Nikiti, Greece, in the '90s.
- Researchers speculate it could be a previously unknown species and one of humanity's earliest evolutionary ancestors.
- These fossils may change how we view the evolution of our species.
Homo sapiens have been on earth for 200,000 years — give or take a few ten-thousand-year stretches. Much of that time is shrouded in the fog of prehistory. What we do know has been pieced together by deciphering the fossil record through the principles of evolutionary theory. Yet new discoveries contain the potential to refashion that knowledge and lead scientists to new, previously unconsidered conclusions.
A set of 8-million-year-old teeth may have done just that. Researchers recently inspected the upper and lower jaw of an ancient European ape. Their conclusions suggest that humanity's forebearers may have arisen in Europe before migrating to Africa, potentially upending a scientific consensus that has stood since Darwin's day.
Rethinking humanity's origin story
The frontispiece of Thomas Huxley's Evidence as to Man's Place in Nature (1863) sketched by natural history artist Benjamin Waterhouse Hawkins. (Photo: Wikimedia Commons)
As reported in New Scientist, the 8- to 9-million-year-old hominin jaw bones were found at Nikiti, northern Greece, in the '90s. Scientists originally pegged the chompers as belonging to a member of Ouranopithecus, an genus of extinct Eurasian ape.
David Begun, an anthropologist at the University of Toronto, and his team recently reexamined the jaw bones. They argue that the original identification was incorrect. Based on the fossil's hominin-like canines and premolar roots, they identify that the ape belongs to a previously unknown proto-hominin.
The researchers hypothesize that these proto-hominins were the evolutionary ancestors of another European great ape Graecopithecus, which the same team tentatively identified as an early hominin in 2017. Graecopithecus lived in south-east Europe 7.2 million years ago. If the premise is correct, these hominins would have migrated to Africa 7 million years ago, after undergoing much of their evolutionary development in Europe.
Begun points out that south-east Europe was once occupied by the ancestors of animals like the giraffe and rhino, too. "It's widely agreed that this was the found fauna of most of what we see in Africa today," he told New Scientists. "If the antelopes and giraffes could get into Africa 7 million years ago, why not the apes?"
He recently outlined this idea at a conference of the American Association of Physical Anthropologists.
It's worth noting that Begun has made similar hypotheses before. Writing for the Journal of Human Evolution in 2002, Begun and Elmar Heizmann of the Natural history Museum of Stuttgart discussed a great ape fossil found in Germany that they argued could be the ancestor (broadly speaking) of all living great apes and humans.
"Found in Germany 20 years ago, this specimen is about 16.5 million years old, some 1.5 million years older than similar species from East Africa," Begun said in a statement then. "It suggests that the great ape and human lineage first appeared in Eurasia and not Africa."
Migrating out of Africa
In the Descent of Man, Charles Darwin proposed that hominins descended out of Africa. Considering the relatively few fossils available at the time, it is a testament to Darwin's astuteness that his hypothesis remains the leading theory.
Since Darwin's time, we have unearthed many more fossils and discovered new evidence in genetics. As such, our African-origin story has undergone many updates and revisions since 1871. Today, it has splintered into two theories: the "out of Africa" theory and the "multi-regional" theory.
The out of Africa theory suggests that the cradle of all humanity was Africa. Homo sapiens evolved exclusively and recently on that continent. At some point in prehistory, our ancestors migrated from Africa to Eurasia and replaced other subspecies of the genus Homo, such as Neanderthals. This is the dominant theory among scientists, and current evidence seems to support it best — though, say that in some circles and be prepared for a late-night debate that goes well past last call.
The multi-regional theory suggests that humans evolved in parallel across various regions. According to this model, the hominins Homo erectus left Africa to settle across Eurasia and (maybe) Australia. These disparate populations eventually evolved into modern humans thanks to a helping dollop of gene flow.
Of course, there are the broad strokes of very nuanced models, and we're leaving a lot of discussion out. There is, for example, a debate as to whether African Homo erectus fossils should be considered alongside Asian ones or should be labeled as a different subspecies, Homo ergaster.
Proponents of the out-of-Africa model aren't sure whether non-African humans descended from a single migration out of Africa or at least two major waves of migration followed by a lot of interbreeding.
Did we head east or south of Eden?
Not all anthropologists agree with Begun and his team's conclusions. As noted by New Scientist, it is possible that the Nikiti ape is not related to hominins at all. It may have evolved similar features independently, developing teeth to eat similar foods or chew in a similar manner as early hominins.
Ultimately, Nikiti ape alone doesn't offer enough evidence to upend the out of Africa model, which is supported by a more robust fossil record and DNA evidence. But additional evidence may be uncovered to lend further credence to Begun's hypothesis or lead us to yet unconsidered ideas about humanity's evolution.
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