That's not at all true. I eat healthy, lots of vegetables, beans, lean meat,and so on, and I go shopping only once every two weeks. Apples keep for weeks, ditto cauliflower in the refrigerator, kale, cabbage, tomatoes, and so on. Meat you can freeze. Dry beans keep forever, and plus there is canned goods.Plus flavorings like salsa in a jar. I waste virtually nothing.
And it is cheaper than living off of processed foods, unless you are living off of pure starches like macaroni and cookies.
You do know have to know how to cook. Nothing fancy, just the basics like boiling beans, chopping vegetables, mixing together a bunch of things to get something that tastes reasonably good. And it does take time.
As for travel, yeah. I started doing a lot more a number of years back and it took me a while to get more disciplined about it. I find it's more about regulating my intake than eating healthy per se. I try to avoid eating just because some food has been laid out for me. And I tend to keep things to one or two full meals a day.
Definitely agree about finding healthy food on the go. Mostly salads.
Healthy food tends to spoil, and if you're not able to go shopping multiple times a week and have unpredictable availability for meal preparation, you're going to see a lot of spoilage. If 30% of your fresh produce ultimately spoils, your actual cost is 43% higher.
Healthy food requires a degree of planning and execution which takes time and focus. Finding healthy options which are appealing for 3x meals a day is a lot of work if you aren't happy with 1 or 2 standbys every day.
Healthy food is extremely hard to find on the go. If you don't have a kitchen at your disposal generally you are shit out of luck for finding something that is truly healthy. So for example, the quality of my diet is highly inversely correlated with the amount of travel I am doing in a given month.
Making unhealthy choices more expensive through taxes is extremely regressive for many of these reasons.