I think the lack of accessible grocery requires people to pile up grocery for weeks, which motivates people to get crappy and over-processed food that last a long time.
This also promotes "one-stop shop" which heavily favors coperate driven big-box store than local specialty store with better and fresher products.
The lack of "natural exercise" from commuting and walking to grocery also worsens the problem.
A lot of the time people thinks "anti-car" is only for some far-fetching environmental argument, yet the over-reliant on cars is really corroding every aspect of our life quality.