Peak Performance was started in  Ottawa, Ontario, by Elizabeth (Beth) Mansfield, PhD, MSc, RD, a Registered Dietitian, Certified Exercise Physiologist, and Sport Nutrition Specialist. Beth is registered with the College of Dietitians of Ontario, the Ordre professionnel des diététistes du Québec, and the Canadian Society of Exercise Physiology. She is also Board Certified in Sports Dietetics (CDR-USA).

  • As a Registered Dietitian and Exercise Specialist, Beth helps people to improve their eating habits, integrate physical activities into their lifestyle, and manage their weight.
  • As a Sport Nutritionist, Beth works with competitive and recreational athletes of all levels and ages to ensure that they are eating for peak health and performance in life and sport. Some of the teams and athletes at the international, national, University, provincial, regional and professional levels benefiting from her nutrition expertise include athletics, rugby, squash, basketball, soccer, tennis, gymnastics, figure skating, cycling (road, track, tandem, para), triathlon, half/full iron-man, cross country skiing, speed skating (in-line and ice), equestrian (jumper, dressage, combined eventing), wrestling, judo, table tennis, goal ball, ringette, hockey, sledge hockey, swimming, water polo, canoe/kayak, and white water kayak .
  • As a workplace wellness advocate, Beth specializes in applying training principles developed for sport performance to business executives and the development of workplace wellness programming for both the government and business sectors.

Dr. Mansfield also conducts social science research using evidence based analysis in a systematic way to answer practical nutrition related concerns/questions.

  • In partnership with the Canadian Association of the Advancement of Women in Sport and Physical Activity (CAAWS) she has conducted research on the physical activity behaviours and beliefs of socioeconomically disadvantaged mothers in Canada.
  • In partnership with McGill University’s School of Dietetics and Human Nutrition, she has investigated individual, social and environmental correlates of weight control in a representative sample of Canadian women involved in training and competing in road running races throughout Canada.
  • For the Bureau of Nutritional Sciences at Health Canada she has systematically integrated a health literacy analytical lens into food and nutrition research. This includes the Canadian adaptation of a health literacy screening tool, The Newest Vital Sign©Pfizer for use in social and behavioural research.

Recent publications:

  • Mansfield, Elizabeth, Rana Wahba, and Elaine De Grandpré. 2020. “Integrating a Health Literacy Lens into Nutrition Labelling Policy in Canada” International Journal of Environmental Research and Public Health 17, no. 11: 4130.
  • Mansfield, Elizabeth D., Dominique Ibanez, Fuqi Chen, Emily Chen, and Elaine de Grandpré. 2020. “Efficacy of “High in” Nutrient Specific Front of Package Labels—A Retail Experiment with Canadians of Varying Health Literacy Levels” Nutrients 12, no. 10: 3199.
  • Miller D, Jones-McLean E, Mansfield ED, Esslinger K, Elvidge Munene L, Dumais L, Verreault MF, St-Pierre S, and M Villeneuve (2015). Health Reports – A surveillance tool to assess diets according to Eating Well with Canada’s Food Guide. Health Reports 82-003-X Vol 26 No.11, Statistics Canada.
  • Sinclair SE, Cooper, M, and ED Mansfield. (2014) The impact of menu labelling on calories selected or consumed: a systematic review and meta-analysis. Journal of the American Academy of Nutrition and Dietetics (Published online July 15, 2014;
  • Sinclair SE, Mansfield ED and GA Wells. (2013). Evidence for a whole grains and coronary heart disease health claim. International Food Risk Analysis Journal, ISBN: 1848-2368, InTech, DOI: 10.5772/56209.
  • Mansfield ED (2013). Correlates of weight control in Canadian women. McGill University E-Thesis.
  • Mansfield ED, Ducharme N and KG Koski (2012). Physical activity behaviours and beliefs of socioeconomically disadvantaged mothers in Canada. International Journal of Nutrition and Physical Activity, 9(42);