AFAIK Japan is the country with the highest life expectancy, and it's a country with an obesity rate below 5%. So yeah.
We're talking about overweight people. I don't think you understand the medical definitions of these terms.
Height is also linked to increased mortality, and Japanese people are shorter. Lots of dietary considerations would need to be factored in. Possible environmental or genetic effects need to be considered. You have to control for variables here. Ceteris paribus, overweight people live longer than lean people.