I agree about fat but, for instance, today fat will make up 38% of my calorie intake. That's because my fats are balanced except for dinner. Dh is cooking and I know he'll add a lot of olive oil to the pan when he cooks up our stirfry. So I'm getting fat from my milk, cheese, dark chocolate, yogurt, meat AND oil. With less oil, I'd still be getting about 25 - 30% of my calories from fat which is amazing compared to my diet before starting this WOE (when I went back and looked and the macro nutrients I was getting between 15 - 20% fat.)
Restaurants use a ton of oil for cooking. It makes cleanup much easier. While I use none for my egg omelet, I'll see at least 2T added when I got to an omelet making station at a restaurant. So that's 200 calories more than the same food prepared at home. That's why eating out 3 meals a day is such a mine field. And that is just with fat.
Even the roast chicken at Subway has sugars added and breakfast potatoes are commonly dusted with flour seasoning in restaurants. So no sugar and flour is a real issue even if you avoid the obvious (no croutons or salad dressing on your salad, no sandwiches, no desserts or candy.)
Given the first rule about weight loss is calories in are less than calories out, when I'm traveling the goal is to find the lowest calorie options period. Adding in other restrictions (no sweeteners, no flour, no potato) is one step too far for me. I do keep macros in mind but out of habit, not as a rule to follow. I just keep asking myself if I'm hungry. If I am, I go with nuts unless I crave sweet in which case I go for raisins. Both travel very well (if you aren't crossing international borders) and I have 'dime bags' for them so they are in reasonable serving sizes within my purse.
Having my Vector protein bars is another real help since at the very least I might save a 200 calorie impulse choice, such as a roll while waiting for my main course to arrive or best case, make better choices while ordering and not having any interest in dessert. But that has sugar so wouldn't work for LadyM.
My final travel strategy is carrying my decaf tea (and a kettle if we are driving) so I can often put off a dessert at a social dinner by promising myself some licorice or mint tea when I get back to the hotel room. That is often enough to make me feel not deprived. We don't usually eat dessert so if it is just dh and I there's no temptation with regards to dessert. With him, onion rings is my Achilles heal since he'll order them and he isn't on an eating plan so can have them.