For years doctors have puzzled over the prevalence of heart disease in patients who are defined as either normal weight or just slightly overweight. This Metabolic Obesity in Normal Weight (MONW) syndrome in individuals carries a much higher risk of heart attack and stroke. The good news is that prompt lifestyle interventions in MONW syndrome may help to lower risk and prevent progression to outright type II diabetes and other associated conditions.
BMI is not the full story: Normal Weight Metabolic Obesity
Source: NIH, American Diabetes Association