The secret Dungeon Meshi sauce that's getting people to eat better is that it's so non-judgmental. Senshi and the rest of the gang never talk about what not to eat besides things that taste bad and literal poison. They don't even talk about "health" that much besides the importance of a balanced diet. It's so much easier to eat well when you think of food simply as something your body needs, and that it's often worth the extra effort to make it taste good, especially when you understand how to connect "things your body needs" with "things that taste good"
I love that when marcille says she really wants some cured ham senshi says "oh that means your body is craving fat which is actually a very good and normal thing. Let's go kill a snake chicken and have a picnic."
One thing people get immediately about Dungeon Meshi is that so much of it is about Dungeons and Dragons. I think a less discussed thing is Dungeon Meshi is also very much about backpacking.
I used to backpack for a living as part of my job and the logistics of how much food I could carry was very much a limiting factor of how far we could get in a week before we had to turn around.
We had to do so much planning about food, I counted calories for the first time in my life not to lose weight but to establish a bare minimum of how much food I needed. I started with 2000 calories before realizing that they decided that number was an average for people who hiked way less then 8 hours in a day. I went up to 2400 calories a day, I would have done more but reasonably I could only carry so much food on my back. I made sure a good portion of it was salty because after the first day my sweat would taste like water and if I didn't pack enough gatorade powder my legs would cramp. Pringles have never tasted as good as they would on day 3 of a hike when my body craved salt the most, at home they were disappointing. Food was about what my body needed and what would let me keep hiking.
I would often train new volunteers and impressing upon them how much food they needed to pack and how they needed to think about it differently was always hard. The hardest was young woman. They would tell me they only ate 1400 calories in a day, they were never hungry after that, they couldn't possibly eat that much. They always listened to me in the second week. No one ever brought enough in the first week man or women.
The logistics of carrying enough food was a frequent topic, we discussed yes, if we were going to a lake, could we fish? Would that be reliable, could we save pack weight and money (dehydrated food is expensive) on that? We would talk about what fresh ingredients we could bring, how long they would keep, how we could cook them. Like a lot of adventurers mention when running into Laio's party, the kind of dried food that goes well in a backpack wears on you after a while, you want something actually cooked, not dried or at best rehydrated. The problems about food they discuss in the manga are the exact same problems I have sat around and discussed with people I worked on the trail with.