William Howard Taft was elected America's 27th president in 1908, and he's known for being the heaviest president ever, weighing in at 340 pounds.

But he's also recognized for something more positive: He's the only president who went on to become a Supreme Court justice.

Taft's biggest achievement, however, may have been his impressive weight loss. Between his one-term presidency and taking his seat on the SCOTUS, he lost 70 pounds, and kept it off for the next 18 years.

How'd he do it? With effective lifestyle changes. He eliminated red meats, bread, potatoes, alcohol, and tobacco.

Unfortunately, before his death in 1930 at age 72 he suffered two heart attacks. At almost 6 feet tall and 270 pounds, he was still obese.

Why is being overweight so damaging to your cardiovascular system? Recent research from the United Kingdom offers a new understanding: Obese people have more immune system CD4+ T-cells than normal-weight people.

These T-cells are designed to help fight off infection, in part by triggering inflammation. But the T-cells proliferate when you accumulate excess body fat (especially belly fat).

They infiltrate that bulging adipose tissue (maybe they're trying to fight it off like an infection), further increasing bodywide inflammation. And that inflammation makes your arteries more vulnerable to becoming stiff, scarred and accumulating plaque that can break off and cause a heart attack or stroke.

So if you need one more reason to stay committed to a healthy diet and weight control, here it is: Being overweight messes with your immune system.