It's not just about fast food or being lazy but about the access to higher food quality. Feeding huge populations isn't easy and here in America we put a lot of sodium/fat/sugar on almost everything that is cheap so they taste like the real thing. Buying meat for someone that has less money won't be easy. Cheap meat comes with fat and a lot of it. People buy hot dog saussages they look ok but inside reside a lot of sugar and fat. Results they get less meat and need to eat more to satiate resulting in eating more fat/sodium/sugar.
Thing about drinking as they are rich in sugar. Cheap drinks contain less real juice but more sugar. Poor people will buy these "juices" as they cost a fraction of the higher quality drinks. Even water costs more than cheap drinks.
Good vegetables cost a lot too. Lower the quality of th evegetables and watch people not buying them as they taste horribly and are a pain to cook.
In my opinion it's all about how you live and how you're raised. Poor people starve more than rich people and when they eat they need to not be hungry anymore so they eat fast and as much as they can, this is a bad habit as it takes time for your brain to realise you're full. Your stomach will have more food to digest than neccessary. It will put good food to good use and the rest will either be evacuated or stored as body fat. If you were raised with bad habits and bad food chances are that you'll keep doing so when you grow up.
I also think that access to cooking methods is also key in an healthy diet. Cooking in a frying pan is faster than using a stove. I seen people using a ridiculous quantity of butter in their pans because they were of poor quality. All this butter will end up in their food and it's extra fat and sodium. Cooking in the oven requires more electricity and knowledge which poor people lack.
It has nothing to do with being a minority eventhough a high percentage of the fat people are from the minorities.
+ When your stomach is filled with too much food you tend to fall asleep or feel lazy so you do less activity. Also it's like a muscle that will expand if you give it too much work. An expanded stomach needs more food to satiate.
