Poor people are likely to be both cash-poor and time-poor: it's not a question of "being bothered". If you have the available time to fully consider, process, and follow this advice, then you may not realistically be poor at all.
And, if you did manage to follow this advice, you would likely still be poor - saving pennies on food is not any way out of poverty.
And lets get off of this no time argument. Why do all these people with no time still have TVs? The average American watches ~5 hours of TV per day. Watch 4 hours instead and cook a healthier and cheaper meal.
That's a complete non-sequitor. You're going to have to provide evidence that those who are poor are the ones watching tv so much, and don't have the time because they're working multiple jobs.
She kept the house stocked with canned soup and lunch meat because a 6 year old (me) and a 12 year old (my brother) could manage to make a meal out of it while she was working.
https://www.cell.com/cell-metabolism/fulltext/S1550-4131(17)...
The research done concluded that differences in Gut Microbiome meant that "The glycemic response to the two types of bread varies greatly across people".
More food for thought (Pun intended :p )
I do think in the general case though, that people usually have 1/2 hour to cook if they wanted to. Are there going to be exceptions like yours? Absolutely.
Which, if you're working 2 jobs, you very well might not have.
"If you're thinking the unhealthy food in the grocery store is cheap, that's also not true."
Time is also a cost. So is the ability to store food.
If you're thinking the unhealthy food in the grocery store is cheap, that's also not true. Chips are $3-$5/bag while 3 pounds of onions is $2. I could go on.