Millennia of Indigenous plant knowledge and the emerging evidence of early human physiological adaptation to carbohydrate consumption chronicle the deep-time origins and trajectories of human–plant relationships. These lines of evidence confront the archaeological orthodoxy of the Pacific Northwest, which has long held that plant foods were of little importance to diets and lifeways of Indigenous peoples. We thank Steve L. Martin for his commentary on our recent article and for providing us with an opportunity to present further evidence for our central contention: that geophytes were a nutritionally important part of the precontact diet, and that they functioned as dietary, cultural, and economic staple foods for many peoples of the Pacific Northwest.

The geophyte plant featured in our 2021 article is wapato (Sagittaria latifolia). The nutritional values of edible wapato tubers are particularly high when compared to many other traditional plant foods. Wapato tubers provide a concentrated source of food energy, protein, carbohydrates, potassium, and magnesium (Kuhnlein and Turner Reference Kuhnlein and Turner2020). They also contain essential micronutrients and vitamins (thiamine, riboflavin, niacin, and vitamin C) involved in energy metabolism and prevention of chronic disease (Shergill-Bonner Reference Shergill-Bonner2017).

There is a growing body of evidence to suggest that complex carbohydrates were significant contributors to early human diets (Hardy et al. Reference Hardy, Brand-Miller, Brown, Thomas and Copeland2015; Inchley et al. Reference Inchley, Larbey, Shwan, Pagani, Saag, Antão, Jacobs, Hudjashov, Metspalu and Mitt2016; Lazaridis et al. Reference Lazaridis, Patterson, Mittnik, Renaud, Mallick, Kirsanow, Sudmant, Schraiber, Castellano and Lipson2014). Perry et alia (Reference Perry, Dominy, Claw, Lee, Fiegler, Redon, Werner, Villanea, Mountain and Misra2007:1256), for example, show that “the pattern of variation in copy number of the human AMY1 gene is consistent with a history of diet-related selection pressures, demonstrating the importance of starchy foods in human evolution.” Early human selection, preparation, and consumption of dietary starch is further supported by the archaeobotanical discovery of fragments of charred starch plant tissue in hearths dating to approximately 120 and 65 kya (Larbey et al. Reference Larbey, Mentzer, Ligouis, Wurz and Jones2019).

Outside of the adaptations of some circum-Arctic populations, humans require a reliable source of glycemic carbohydrates for the healthy function of the brain, the kidney medulla, red blood cells, and reproductive tissues (Hardy et al. Reference Hardy, Brand-Miller, Brown, Thomas and Copeland2015:255). In the absence of carbohydrates, the brain will utilize ketones, a bi-product of fat oxidation, which meets around 80% of the brain's energy requirement. In a carbohydrate-free diet, there remains an absolute requirement for 30–50 g (Institute of Medicine 2005) of glycemic carbohydrate to fill the gap between gluconeogenic capacity and the brain's requirement for glucose (Hardy et al. Reference Hardy, Brand-Miller, Brown, Thomas and Copeland2015; Westman Reference Westman2002).

Martin (Reference Martin2022) suggests that the year-long, animal-source-foods-exclusive diet of Arctic ethnologist Vilhjálmur Stefánsson “conclusively demonstrated [that] humans do not need to consume plants, the main source of carbohydrates in most human diets, to survive.” Evidence of gut microbiome adaptations certainly show selective adaptation of Arctic populations to a protein-rich diet (Dubois et al. Reference Dubois, Girard, Lapointe and Jesse Shapiro2017), but archaeobotanical and ethnobotanical knowledge from those same populations indicates that this adaptation is not one that excludes plant foods (Boulanger-Lapointe et al. Reference Boulanger-Lapointe, Gérin-Lajoie, Collier, Desrosiers, Spiech, Henry, Hermanutz, Lévesque and Cuerrier2019; Cuerrier et al. Reference Cuerrier, Clark and Norton2019; Kuhnlein et al. Reference Kuhnlein, Barthet, Farren, Falahi, Leggee, Receveur and Berti2006; Zutter Reference Zutter2012). The Inuvialuit community into which the rather notorious Stefánsson married, for example (Pálsson Reference Pálsson2005), maintains knowledge and use of well over 100 plants in their local economies, including many berries and root foods (Inuvialuit Elders and Bandringa Reference Elders and Bandringa2010); archaeobotanical studies confirm these uses some 500 years ago (Lyons et al. Reference Lyons, Hodgetts and Haogak2021).

The concept of a food as a staple extends significantly beyond its immediate role as a source of nutrition. Food can become a socioeconomic resource staple if it is produced at sufficient levels and standardized forms that it can become a tax or tithe in a redistributive economic system (Earle and D'Altroy Reference Earle, D'Altroy, Ericson and Earle1982). Dietary staples include a wide range of plant and animal foods that can be reliably produced and/or stored in sufficient abundance to forestall periods of food shortage; be used for trade, exchange, or tribute; or provide a surplus that can underwrite labor for a wide range of activities beyond the food quest itself. A rich record of oral histories, ethnobotanical knowledge, historical documents, and archaeological evidence supports the contention that wapato met all of these criteria and functioned as one of several such socioeconomic resource staples for Katzie and many other Indigenous peoples of the Pacific Northwest (Garibaldi Reference Garibaldi2004; Hoffmann et al. Reference Hoffmann, Lyons, Miller, Diaz, Homan, Huddlestan and Leon2016; Lyons et al. Reference Lyons, Hoffmann, Miller, Huddlestan, Leon and Squires2018; Spurgeon Reference Spurgeon2001; Suttles Reference Suttles1955; Turner et al. Reference Turner, Armstrong and Lepofsky2021).

Martin's critique usefully asks us to consider the complexities of what constitutes food staples in cultural and dietary contexts. However, his analysis asks us to narrow the definition of a staple food to a dietary and nutritional value rather than considering the important cultural—and especially economic—qualities of food. Even by Martin's narrow view, wapato is a food staple to Katzie. A broader consideration of its value permits a richer understanding of the history of resource management among the Katzie and many of their neighbors throughout the Pacific Northwest Coast region.