EMT showing differences between the annual diets of bear populations receiving anthropogenic subsidies versus natural diets. Means (filled symbols) are shown with 90% and 99% confidence regions. The blue line represents the preferred optimal proportion of protein (17% ± 4) selected by captive bears. Isoproportion lines represent 1:1 proportions of protein and lipid (radiating from the 100% carbohydrate corner) and carbohydrate and lipid (radiating from the 100% protein corner)