Aim To determine healthcare professionals’ knowledge of the calorie content of foods and the relationship to weight maintenance. Method A cross-sectional questionnaire was used to survey 179 clinical staff, non-clinical staff and life coaches working in health care. Results The response rate is 81%. The majority of respondents identified the weight loss requirements necessary to achieve marked health benefits in obese patients. Estimation of calorie and salt contents of specified foods was generally inaccurate. The majority of healthcare professionals did not know the amount of exercise required to burn off the calories of commonly consumed foods. Conclusion Support and education are required for healthcare professionals to manage the challenges associated with obesity.