Most of the foodstuffs offered on discount end up being fresh prepared salads w/ salmon, whole chicken, roasted vegetables, etc. The time cost for preparing all of these properly at home is substantial.
Given that I don't buy groceries anymore, I don't have food available at home to snack on. If I want food I need to prepare rice or some other primary grain. These dishes have a significant lag-time between the impulse to eat and the dish's completion, so this prompts me to ask "am I really hungry or just bored with what I'm doing?". Often, I'm bored. I'll pop open a new book or change up what I'm doing instead of downing 400cals. Even if I do give in and prepare a bit extra, I'm still under my daily limit by a substantial amount.
The alternative, grocerywise, costs me approximately the same amount when accounting for spoilage and time. I love cooking, but the time cost associated with shopping alone (let alone preparation) puts the expected monthly cost of preparing food at home over 11$/day for me.
Accordingly, it doesn't make sense for me to shop for groceries. I'll keep a few vegetables (cucumbers, cabbage, etc.) or soups available for moments when I'm in a pinch (sick/extra hungry/very active days etc), but otherwise I just wait.
I'll likely look at adding pure-protein home-cooked options when I start hitting the gym hard in a few months, but I've bulk purchased fish and steaks from importers and local meat packers respectively at 1/3rd of their normal retail price anyways, so I'm good to go on that front.
It's irritating to change but after a while you start to appreciate when you can just keep yourself within your daily cycle with work and location you're accustomed to.
I take it as a lesson to know how to soften the next hit.
I never took a budgeting class in high school and college, my parents lived paycheck to paycheck (still do), when I earned my first internship I was making over $1000 per pay period, that was a lot of money for someone who had only worked part time jobs for $10/hr before hand.
By the time I got my second internship I earned more than my mother, who was the breadwinner. Once I was converted to full time I had more money than I knew what to do with. It took a few months to stop making stupid purchases, learn how to budget, save, and invest. Painful lesson.