I normally go for nandos and have chicken breast with ratatouille (not sure of it's 100% dukan though). I had a Frankie and Bennies last week I went for salmon and asked for extra veg and salad instead of potatoes
I'm finding most restaurant will cater for you. I've eaten out in brewers fayre type places and the eat eat ? Chains none of them have had any problems giving me fresh veg instead of potatoes or chips with my meals I usually have steak or venison depending where we are eating
I'd be very careful of chains like McDonalds because things like "Grilled Chicken" are usually "Chicken dipped in a vat with caramel, salt and cornflour, frozen, dusted with more salt, sugar and cornflour, packed, shipped, reheated".
McDonald's fries for example were (are still?) routinely coated in beef tallow before they were frozen, even though they were advertised as "fried in veg oil"
I reluctantly had to bring my nephew there a good many years ago because he wanted a 'Happy Meal' but he was so little and all he wanted was the toy so I binned the crap food, gave him the toy and we ate somewhere decent!!! *worst auntie ever!*