I'm pretty sure it's cheaper to go to McDonalds and get junk food than get a nutrious meal so there's that.
SNAP is a subsistence level benefit, which means people will go as cheap as possible, in the US sadly enough, that means junk food more often than not.
That's not true at all.
They trade SNAP bennies for junk food because it is more convenient to simply open a package and eat, and because they have learned to eat this way.
Beans and rice should be the staple of any low-income person's diet. They are very cheap and very nutrient dense. If bought dry by the bag, they are pennies per meal. I once worked part-time for two years, with a stay-at-home wife, so I could complete a college degree. At that time, we had four boys and a girl on the way. We ate a lot of beans and rice.
With B&R taking care of caloric needs, fiber, protein and hunger, our remaining grocery money was spent on salad veggies, heavy on the raw spinach, one of the most vitamin and mineral rich foods you can eat, tomato paste for making sauces, spices to flavor everything, and either chicken or ground beef. Oatmeal and eggs for breakfast. The only place where we didn't skimp was bread.
The main ingredients: willingness to spend the time preparing these meals, and willingness to forego the non-nutritional food that SNAP recipients are encouraged to purchase.
Are their meals that are healthy AND easy? Not as healthy as what I describe above, but much healthier than Hot Cheetoes and Hawaiian Punch. Lunchables and a variety of frozen meals come to mind. Microwaveable meals.