I’m always skeptical on eating out on keto, just like a person who is allergic to peanuts is afraid to buy a milk chocolate, because the wrap says it may contain small traces. The problem is, the menus from the restaurants don’t yell at you “Don’t eat this, it will throw you out of ketosis”.
The safest places to eat are the steak houses, since it’s unlikely to have the cook add flour on your steak, if it is not prepared as a schnitzel. You may think I exaggerate, but it happened way to often to see a presumably LCHF product in a menu (with ingredients written under its name), and find out it had high carb ingredient left out. For instance, most creamy soups you see (like mushrooms, celeriac, cauliflower, cheese and so on) have a “secret” ingredient which gives them the creamy aspect: the so blamed by low-carbers potato. A mashed potato can do wonders for the chef and they won’t keep away from using it.
Perhaps the most feared high carb ingredients, the humble flour and its partner, the sugar, are found way to often in restaurant main dishes: mayo, tomato sauces, stews, cheese dips, hot wings, they all may have added sugar or flour, for consistency and taste reasons. It may not be too much, but enough to take you out of your track.
Therefore, when going out, don’t order complicated dishes. Go as simple as you can and if you have any doubts, you are entitled to ask for the exact recipe the chef is using, for health reasons.