Annual diet variation in macronutrient proportions was not equal; however, as across populations, the greatest variation was observed for carbohydrate, while protein and lipid were more codependent. The nutritional explanation for this is that animal prey is a source of both protein and lipid, with negligible carbohydrate content (Coogan et al., 2014). The highest proportion of protein in annual diets, and lowest proportion of carbohydrate, was found in Canada's central Arctic, where bears displayed high levels of predation on caribou (Rangifer tarandus) and ground squirrels (Spermophilus parryii; Gau et al., 2002). Diets relatively high in carbohydrate occurred in ecosystems where bears consumed starchy roots (e.g., Hedysarum alpinum) and fruit (e.g., Munro, Nielsen, Price, Stenhouse, & Boyce, 2006). However, carbohydrate proportions were highest in annual diets with anthropogenic subsidies, such as agricultural crops and supplemental feeding of corn, oats, and wheat (e.g., Paralikidis, Papageorgiou, Kontsiotis, & Tsiompanoudis, 2010; Rigg & Gorman, 2005; Sato, Aoi, Kaji, & Takatsuki, 2004; Stofik, Merganic, Merganicova, & Saniga, 2013). Similarly, the proportion of lipid in annual diets was highest in populations that consumed relatively more domestic livestock (e.g., Clevenger, Purroy, & Pelton, 1992; Dahle, Sorensen, Wedul, Swenson, & Sandergren, 1998). Therefore, our results support the hypothesis that bear diets including anthropogenic food subsidies are, on average, higher in proportions of nonprotein macronutrients, especially carbohydrate.