Background & aims: Obesity, defined as a BMI ≥ 30 kg/m 2 , has demonstrated protective associations with mortality in some diseases. However, recent evidence demonstrates that poor nutritional status in critically ill obese patients confounds this relationship. The purpose of this paper is to evaluate if poor nutritional status, poor food intake and adverse health-related outcomes have a demonstrated association in non-critically ill obese acute care hospital patients. Methods: This is a secondary analysis of the Australasian Nutrition Care Day Survey dataset (N = 3122), a prospective cohort study conducted in hospitals from Australia and New Zealand in 2010. At baseline, hospital dietitians recorded participants’ BMI, evaluated nutritional status using Subjective Global Assessment (SGA), and recorded 24-h food intake (as 0%, 25%, 50%, 75%, and 100% of the offered food). Post-three months, participants’ length of stay (LOS), readmissions, and in-hospital mortality data were collected. Bivariate and regression analyses were conducted to investigate if there were an association between BMI, nutritional status, poor food intake, and health-related outcomes. Results: Of the 3122 participants, 2889 (93%) had eligible data. Obesity was prevalent in 26% of the cohort (n = 750; 75% females; 61 ± 15 years; 37 ± 7 kg/m 2 ). Fourteen percent (n = 105) of the obese patients were malnourished. Over a quarter of the malnourished obese patients (N = 30/105, 28%) consumed ≤25% of the offered meals. Most malnourished obese patients (74/105, 70%) received standard diets without additional nutritional support. After controlling for confounders (age, disease type and severity), malnutrition and intake ≤25% of the offered meals independently trebled the odds of in-hospital mortality within 90 days of hospital admission in obese patients. Conclusion: Although malnourished obese experienced significantly adverse health-related outcomes they were least likely to receive additional nutritional support. This study demonstrates that BMI alone cannot be used as a surrogate measure for nutritional status and warrants routine nutritional screening for all hospital patients, and subsequent nutritional assessment and support for malnourished patients.