You just need to be more disciplined. Easier said than done I know, and maybe you're staying in hotels without gyms or whatever who knows. But start by maybe just ordering smaller portions, avoid carbs to an extent, monitor the calories if that works for you.
Another great method, intermittent fasting. I find it quite easy to incorporate that into my schedule. The more consistent you can be with IF the easier it becomes. Even if you're not looking to LOSE weight, it's just a good way to not go over a calorie limit you may or may not set for yourself. Instead of having 3 meals in a day, go down to 2 and magically your calorie count has dropped a bunch. Getting down to 1 meal a day isnt necessarily difficult if you gradually shorten your IF eating window. The problem is the intake, it's easy to fall into a pit of eating a GIANT meal knowing it's your only one. But again, with practice, your appetite will come down a bit and then crushing that huge meal becomes undesirable.
The hardest time for me to IF is when I'm switching time zones and don't have a schedule. When I'm working a relatively set day, or if I've got a whole day off, then it's easy. But if you're flying, especially in economy, they kinda bring food around and you know if you don't eat then, you might not get to for a while. Then you get to a destination and you kinda gotta reset, but same as your body clock, the body food clock (at least for me) can be forced into that reset. Just stay awake until an appropriate time, and eat with your regular window.