Lousy comparison. Cheapest junk food vs prime fresh fruit on calories is disingenuous. More honest would be to include the cost of enough junk food to get needed nutrients.
Junk food is expensive vs a BALANCED frugal purchase. Bread flour is $20 for a 50 pound bag, veggies are $1/lb frozen, other nutrient sources are needed only in small quantities and available in other cheaper forms than fresh from Whole Foods. I can feed you a nutritionally balanced diet on $1 per meal.
I know educated and informed people can do so. I once plotted out a six month plan for one person on food stamps where by the end of the six months, he could regularly feed a squad of people with balanced meals.
But most people have no education how to do this well. A large number spend food stamp money exclusively on rice and beans.
And that is also the other problem, that they don’t want to eat nutritious food. In WWII, a large part of the US Army would only eat grits. Though granted, their other choices of things like fatty, fried bologna and half-spoiled salmon were not that great either.
One veteran I knew who had a better appreciation of nutrition just gorged himself on salad on the one time it was provided, unknowing that the dressing was made with mineral oil, which made its presence known while he was standing in formation later.
He also noted that the breakfast bologna made him and some of his peers regularly throw up after breakfast, so they decided to stand outside the mess hall and vomit on its steps. The “good old days”.
In any event, try to avoid falling into the trap that caught Michelle Obama, because food, for better or worse, is one of the most important personal choices that people have.