From my experience, eating it is even more difficult than was made out to be. Not if you are eating out alone - then you can to to whatever keto or vegan restaurant you choose. The issue is if you are eating out with others - which is usually the case. Then you are first faced with filtering out 90% of all restaurants, and getting everyone who had planned to go to accept that filtering.
If you're only worried about calorie counting (the method discussed in the article) most restaurants are going to have dishes for which you can fairly accurately estimate the calories (with some experience). Tricks like ordering dressing/sauce on the side can make it easier.
Fat has the highest calorie density of any ingredient with 9 calories per gram (sugar has 4). If you're really unsure, you can use that as an upper limit.
