It only counts as moral weakness if you're blaming your own obesity on somebody other than yourself. Most people people who are fat are quite happy with eating a bunch of junk food, so they just have different priorities.

If you have have access to $1 frozen veggie bags, $2/lb chicken thighs, and assortment of different legumes, you have it better food options than the majority of the world. You can certainly achieve a healthy diet if you really want to.