After returning from Europe, Davis moved to Oakland, California in 1931 and worked as a consulting nutritionist for doctors at the Alameda County Health Clinic. Two years later she moved to Los Angeles to do consulting at a medical clinic in Hollywood. She also enrolled at the University of Southern California in Los Angeles where she earned a master of science degree in biochemistry, in 1938. She worked as a consulting nutritionist in Oakland and then in Los Angeles with physicians at the Alameda County Health Clinic and the William E. Branch Clinic in Hollywood. She also prescribed diets to the patients that were referred to her by numerous specialists.