The relationship between Body Mass Index (BMI) and mental health has been widely investigated, and recent evidence has shown that overweight and obese individuals may be more vulnerable to the development of anxiety and mood disorders than individuals of a normal weight. This article examines the association between BMI and mood states of mentally healthy adults. BMI and Brunel Mood Scale (BRUMS) scores, and other demographic information, was collected from healthy adults over a six month period (N = 1621). When age was controlled, only a small but significant negative correlation between BMI and Depression in men was found, which stands in contrasts to previous studies. This may be due to the sample of mentally healthy adults with less incidence of severe obesity due to their military background. Further, African samples may have different expressions for non-clinical distress than industrialised countries which may lead to skewed results. The findings suggests that measures of transient mood states, like the BRUMS, may not be particularly useful in investigating relationships between mental health constructs and anthropometric measures, like BMI.