It's possible, but often it's bad death certificate writing. Let's say a fat fuck has a heart attack, and goes to the hospital. The blood pressure is low, the lungs are filling with fluid as the left ventricle isn't pumping the blood out, so they intubate it, and put it on some blood pressure support while they try to get some blood to the heart. Most common infection at that point: pneumonia. Bad cause of death paperwork would list that as the cause of death. Good death certificate writing would say cause of death complications of myocardial infarction, contributing factors: being a fat fuck, pneumonia, beetus. TL;DR: you're right, but medical treatments and bureaucracy sometimes make it look otherwise at first glance.