Physicians are accustomed to making decisions based on information regarding the prevalence of disease, symptoms, physical signs, laboratory test results, and the risks and benefits of alternative treatments. If nutritional assessment and therapeutics are to become more common components of medical practice, significant barriers in each of these areas must be overcome. Even rudimentary dietary assessment is often missing from physician education. Dietary assessment tools that are readily available and that have demonstrated usefulness are largely unknown. In addition, many nutritional interventions have not been formally investigated in randomized, controlled trials, and thus their cost-effectiveness remains unknown. We present one approach to these issues by discussing the construction of a decision model examining strategies for vitamin D and calcium screening. The application of medical decision making techniques to problems in clinical nutrition illustrates how findings from research studies may be used to determine the risks, benefits and costs of alternative population based health related nutrition policies which can then be applied by physicians in their daily interactions with patients.