Several mechanisms could underlie the independent effect of overweight on coronary heart disease, the researchers said. These include, low-grade inflammation, endothelial dysfunction, hemostatic imbalance favouring coagulation, impaired endothelial vasodilatory responses, left ventricular hypertrophy, and reduced heart rate variability. Furthermore, they said, overweight is associated with an increased risk of diabetes.
If you look at these issues they include things that we have addressed in posts in the past on this blog. For example we have mentioned trying to reduce inflammation and interval training is a good strategy to improve heart rate variability.
However, it is worth noting what the researchers say (and this is true for all science):