There are a lot fewer minorities in Canada. Demographics are different. Minorities in the USA pull our life expectancy numbers down.No doubt that the consumption of processed foods, lack of activity and so forth is to blame for America's poor life expectancy. Those are all issues that should be addressed via preventative care.
However, those same criticisms apply to Canada as well. Canadians probably eat just as much processed food and are as inactive as Americans are. However, the American life expectancy pre-Covid was 77 years. Post- Covid it is 76 years. This is according to the CDC. Canada's life expectancy is 82 years. That's a pretty big gap considering the Canadian diet and lack of physical exercise is just as bad.