Not just 'the poor' have an unhealthy diet. Fast food, junk food, and processed foods cause alot of America's health problems across social strata.
And 'the poor' in the United States are better fed than most of the rest of the world
Law Enforcement cannot bring 'order' to the problem cities for several reasons.
Chief among these is the failed "War on Drugs". Prohibition leads to black markets. Black markets lead to turf wars. Turf wars lead to violence
Another is a culture treating LEO as 'the enemy' rather than respecting the service they provide to the general public