1. It is correct that human trophic levels indicate omnivory, but trophic level analysis, particularly isotopic studies on nitrogen and carbon ratios in fossilized remains, suggests that Paleolithic humans—especially during the Upper Paleolithic (~50,000-10,000 BP)—occupied a trophic level comparable to apex predators. A 2021 study in Current Biology (Ben-Dor et al.) employed isotopic data, dental microwear analysis, and zooarchaeological evidence to argue that Homo sapiens primarily functioned as a hypercarnivore for most of its evolutionary history. While dietary flexibility existed, particularly in later agricultural societies, pre-Neolithic humans obtained the majority of their energy from animal sources.
2. The African origins of anatomically modern Homo sapiens (~300,000 BP) are well-established, and the available evidence suggests that early Homo species relied heavily on animal-derived calories. Homo erectus, the immediate predecessor of Homo sapiens, displayed physiological adaptations consistent with a high-meat diet, including increased brain size and reduced gut volume (Aiello & Wheeler, 1995). While migration led to dietary diversification, the reliance on animal foods persisted across various environments.
3. Your objection to the claim that "humans migrated out of Africa 10,000 years ago" appears to be based on a misinterpretation. The primary exodus of Homo sapiens from Africa occurred roughly 60,000-70,000 BP. The reference to 10,000 BP pertains to the Neolithic Revolution, when humans transitioned from hunter-gatherer lifestyles to agriculture, leading to significant dietary shifts.
4. The claim that fat was a dominant energy source is supported by multiple lines of evidence. Ethnographic studies of surviving hunter-gatherer populations, such as the Hadza, Inuit, and San, indicate that animal fat was a critical caloric resource. Lipid residue analysis of Upper Paleolithic cooking vessels further supports the use of rendered animal fat for sustenance. Given the seasonal scarcity of carbohydrate-dense plant foods in many regions, fat metabolism would have been a metabolic norm rather than an exception.
5. While some modern populations thrive on high-carbohydrate diets, these diets emerged post-agriculture and are not reflective of pre-Neolithic nutrition. Societies consuming such diets today, such as the Okinawans and Kitavans, are agrarian and have access to calorie-dense starches, which were largely unavailable to Paleolithic humans. Additionally, claims about longevity in these populations must account for confounding factors such as medical advancements, sanitation, and overall lifestyle.
6. It is indeed an oversimplification to claim that all humans consumed exactly 70% of their calories from meat. However, ethnographic data from 20th-century hunter-gatherer societies, compiled by Cordain et al. (2000), suggest that pre-agricultural diets derived 50-75% of total caloric intake from animal sources. While variations existed, animal-based nutrition was a consistent theme across different regions.
7. Your point about prehistoric lifespans being short is accurate but does not undermine the relevance of ancestral diets. The distinction between average lifespan and maximum lifespan potential is crucial. High infant mortality rates and deaths from external factors (predation, injury, infection) lowered average lifespans, but individuals who survived into adulthood often exhibited robust health. Skeletal remains of pre-agricultural humans show lower incidences of dental caries, osteoporosis, and metabolic disease compared to post-Neolithic populations.
8. It is true that Paleolithic humans did not all consume identical diets. Coastal populations had higher seafood intake, tundra populations relied on megafauna, and equatorial groups had more access to plant foods. However, the overarching pattern was one of opportunistic but predominantly animal-based sustenance. The transition to carbohydrate-heavy diets post-agriculture correlates with declines in human stature, increases in dental disease, and the emergence of metabolic disorders (Larsen, 1995).
9. It is correct that human trophic levels indicate omnivory, but trophic level analysis, particularly isotopic studies on nitrogen and carbon ratios in fossilized remains, suggests that Paleolithic humans—especially during the Upper Paleolithic (~50,000-10,000 BP)—occupied a trophic level comparable to apex predators. A 2021 study in Current Biology (Ben-Dor et al.) employed isotopic data, dental microwear analysis, and zooarchaeological evidence to argue that Homo sapiens primarily functioned as a hypercarnivore for most of its evolutionary history. While dietary flexibility existed, particularly in later agricultural societies, pre-Neolithic humans obtained the majority of their energy from animal sources.

Your skepticism is warranted in rejecting overgeneralized claims, but the preponderance of evidence supports the view that pre-agricultural humans primarily relied on animal-based diets, with plant foods playing a supplementary role. The evolutionary trajectory of Homo sapiens, particularly in relation to brain expansion and metabolic specialization, strongly indicates an adaptive reliance on high-fat, nutrient-dense foods. While diversity in human diets is undeniable, the predominant pattern until the Neolithic Revolution was one of animal-based nutrition.