How Did Ancient Humans Stay So Lean?

WHY DIDN'T ANCIENT HUMANS GET FAT? For most of human history, food was very different from what surrounds us today. Ancient hunter-gatherers walked long distances, hunted, dug for roots, collected berries, gathered honey, and carried food across difficult terrain. It seems obvious that all of this physical activity should have made them burn dramatically more calories than modern people. But when scientists actually measured energy expenditure in the Hadza hunter-gatherers of northern Tanzania, the result was surprising. Their daily energy expenditure was not dramatically higher than that of people living in industrialized societies. So if they were moving so much, why did they remain so lean? This video explores the scientific evidence behind that mystery. We look at Herman Pontzer's research on Hadza energy expenditure and the doubly labeled water method used to measure calories burned in real-world conditions. We examine the "constrained energy expenditure" model, which suggests that the human body can compensate for increased physical activity by reducing energy expenditure elsewhere. We also look at what the Hadza actually eat: wild tubers, berries, baobab fruit, meat and honey. Surprisingly, honey can make up a substantial part of the Hadza diet, showing that hunter-gatherer diets were not simply "low sugar" diets. The video then explores another major difference between traditional foods and the modern food environment: how easy food is to obtain and consume. A wild tuber requires digging. Honey may require climbing a tree and dealing with bees. Meat requires hunting. Berries have to be found and collected. Modern food can be opened and eaten within seconds. We also examine research on the Hadza gut microbiome, which has shown seasonal changes in microbial communities corresponding with changes in the foods available throughout the year. Then comes one of the most important experiments in modern nutrition. In 2019, Kevin Hall and colleagues conducted a controlled inpatient study at the NIH Clinical Center in which adults were given either an ultra-processed diet or an unprocessed diet for two weeks each. The diets were designed to be closely matched for calories presented, macronutrients, sugar, sodium and fiber. Yet participants voluntarily consumed substantially more calories while eating the ultra-processed diet and gained weight during that phase. So what does all of this tell us about the difference between ancient environments and the modern food environment? This isn't a simple story about "exercise more" or "eat less." It is a story about energy expenditure, food structure, fiber, food availability, eating speed, processing, appetite and the environment in which human biology evolved. We also examine the famous Venus of Willendorf and why a prehistoric figurine cannot tell us what the average Paleolithic human body actually looked like. RESEARCH & SOURCES: ▸ Pontzer et al. — "Hunter-Gatherer Energetics and Human Obesity" (2012, PLOS ONE) DOI: 10.1371/journal.pone.0040503 ▸ Pontzer et al. — "Energy Expenditure and Activity Among Hadza Hunter-Gatherers" (2015, American Journal of Human Biology) DOI: 10.1002/ajhb.22711 ▸ Pontzer et al. — "Constrained Total Energy Expenditure and Metabolic Adaptation to Physical Activity in Adult Humans" (2016, Current Biology) DOI: 10.1016/j.cub.2015.12.046 ▸ Smits et al. — "Seasonal Cycling in the Gut Microbiome of the Hadza Hunter-Gatherers of Tanzania" (2017, Science) DOI: 10.1126/science.aan4834 ▸ Hall et al. — "Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain" (2019, Cell Metabolism) DOI: 10.1016/j.cmet.2019.05.008 ▸ Pontzer, Wood & Raichlen — "Hunter-Gatherers as Models in Public Health" (2018, Obesity Reviews) DOI: 10.1111/obr.12785 ▸ Marlowe et al. — "Honey, Hadza, Hunter-Gatherers, and Human Evolution" (2014, Journal of Human Evolution) DOI: 10.1016/j.jhevol.2014.03.006 ▸ Ruff — "Body Size, Body Shape, and Long Bone Strength in Modern Humans" (2000, Journal of Human Evolution) DOI: 10.1006/jhev.1999.0322 ▸ Naturhistorisches Museum Wien — Venus of Willendorf research and archaeological documentation The figurine was discovered in 1908 and is dated to approximately 29,500 years ago. If you enjoy evidence-based stories about ancient humans, evolution, anthropology, prehistoric life and the strange realities of human history, make sure to SUBSCRIBE to the channel. LIKE the video if you want more research-based ancient human stories. COMMENT below: Would you survive for one month eating only food that you had to find yourself? #ancienthumans #prehistoriclife #humanhistory #evolution #anthropology #huntergatherers #hadza #humanorigins #prehistorichumans #ancienthistory #evolutionarybiology #humanbody #nutrition #foodhistory #humanhealth #science #sciencedocumentary #history #prehistoric #stoneage #paleolithic #paleoanthropology #humanbehavior #ancientworld #documentary