There is evidence that type 2 diabetic patients have a significant risk of heart failure. Rodent studies have demonstrated that in obesity and type 2 diabetes, lipid accumulation in cardiac myocytes is associated with lipotoxicity and consequent heart failure. In vivo magnetic resonance spectroscopy was therefore used to quantify myocardial triglyceride content and left ventricular function in 134 individuals divided into four groups: 1. normal weight (BMI<25 kg/m2) with normal glycemia (2 hour glucose<7.8 mmol/L), 2. overweight/obese (≥25 kg/m2) with normal glycemia (2-hour glucose<7.8 mmol/L), 3. impaired glucose tolerance (2-hour glucose 7.8-11.1 mmol/L), and 4. type 2 diabetes (2-hour glucose≥11.1 mmol/L). This study found that myocyte triglyceride accumulation was 2.3-fold higher in subjects with impaired glucose tolerance and 2.1-fold higher in patients with type 2 diabetes. The left ventricular ejection fraction was normal and similar across all groups. These results suggest that lipid overstorage in human cardiac myocytes can occur early in the development of type 2 diabetes and is present even before the onset of heart failure.