On food: keep it simple, no restaurants, something you can prepare fast. My day diet is: 1 apple + some peanut butter, 4-6 slices of Wasa, 200gr of good quality salumi, eggs, some cheese. My evening diet is: ~0.5kg of fresh vegetables in a salad, 100-150gr of meet or fish. That’s the same everyday, excluding Sundays when I take some breaks from it.
It’s low carb, you don’t have to go low carb, but the main idea here is that if you keep it simple you make it easy for you to: 1) create a habit of eating healthy food; 2) create a habit of eating less or enough; 3) have food available throughout the day in almost any situation; 4) get less food poisoning(?)
Then once or twice a week take a break, go to a restaurant, eat something you like. Every few weeks, take few days of break to eat “normal”.
On exercise: go to a gym and spend 3 to 4 hrs a week there focusing on fundamentals. Or do 2 hrs of gym and 1-1.5 of running. I think if you leave in a place for longer than a week, you should be able to find a gym and a place to run.