Bernice Lydia Kunerth was born on June 10, 1910, in Ames, Iowa, where her father, William Kunerth, served as a physics professor at Iowa State College (precursor to Iowa State University). She had one younger sister named Ruth. In 1932, she graduated with a combined major in foods, nutrition, and chemistry from Iowa State College. The following year, she earned her Master of Science degree at Kansas State University. Until 1938, Kunerth remained in Manhattan, Kansas, where she served as a food/nutrition research technician and instructor. She then went to New York and acquired a Ph.D. in Nutrition Chemistry from Columbia University in 1940. After a brief stint as an assistant professor, Kunerth underwent a few changes that would prove lasting. She moved to Washington, D.C. to begin a career working for the United States Department of Agriculture in 1941 and married Raymond Dewey Watt, a 1922 graduate of Iowa State College, on 1 Nov. 1942.

Her career with the USDA entailed nutritional research. She retired in 1974 as Leader of the Nutrient Data Research Center. Under her leadership, the information available has grown from two tables containing data on 13 nutrients in 275 foods to 20 tables consisting of values for 50 nutrients and 3,000 foods. For her efforts, Watt has received some impressive honors: in 1969, the Distinguished Achievement Citation from Iowa State; in 1972, the Borden Award for fundamental nutrition and experimental foods; in 1974, the Distinguished Service Award from the USDA; and in 1980, the Elvehjem Award for Public Service in Nutrition. All of these scientific accomplishments coincided with her duties as a mother of three and volunteer work she performed in Fairfax, Virginia. She died on March 8, 1984.