How ancestral subsistence strategies solve salmon starvation and the "protein problem" of Pacific Rim resources.

Abstract

This article provides a theoretical treatment of hunter-gatherer diet and physiology. Through a synthesis of nutritional studies, informed by ethno-archaeological data, we examine the risk of protein-rich diets for human survival, and how societies circumvent "salmon starvation" in the northeastern Pacific Rim. Fundamental nutritional constraints associated with salmon storage and consumption counter long-standing assumptions about the engine of cultural evolution in the region. Excess consumption of lean meat can lead to protein poisoning, termed by early explorers "rabbit starvation." While consumption of fats and carbohydrates is widely portrayed as a pathway to "offsetting" protein thresholds, there are true limits to the amount of protein individuals can consume, and constraints are most extreme for smaller individuals, children, and pregnant/nursing mothers. While this problem is not usually perceived as associated with fish, the risk of protein poisoning limits the amount of low-fat fish that people can eat safely. Compared with smaller, mass-harvested species (e.g., eulachon), dried salmon are exceedingly lean. Under certain circumstances fattier foods (small forage fish, marine mammals, whales, and even bears) or carbohydrate-rich plants may have been preferred not just for taste but to circumvent this "dietary protein ceiling." Simply put, "salmon specialization" cannot evolve without access to complimentary caloric energy through fat-rich or carbohydrate-rich resources. By extension, the evolution of storage-based societies requires this problem be solved prior to or in tandem with-salmon intensification. Without such solutions, increased mortality and reproductive rates would have made salmon reliance unsustainable. This insight is in line with genomic research suggesting protein toxicity avoidance was a powerful evolutionary force, possibly linked to genetic adaptations among First Americans. It is also relevant to evaluating the plausibility of other purportedly "focal" economies and informs understanding of the many solutions varied global societies have engineered to overcome physiological protein limits.