If you'll find an app like this, try to do an experiment: estimate calories by taking a picture, then add 30g of olive oil (270 kcal) to the same dish and see if the app will detect it.

Heh, and the same goes for using a traditional nutrient tracker for a meal you ordered at a restaurant.

Nutrient/calorie tracking really only works if you measure the raw inputs or use a packaged product that gives you the info, and I imagine those are also the two cases that the AI can estimate visually.