FoodCoach
Food studies are currently based on recall... and peoples recall is horrible. "What did you eat last Monday for breakfast, and how many grams of it did you eat?" The inputs are garbage and the outputs are garbage. Linking actual food intake to healthout comes would be VERY powerful.
It also excludes going out to eat. That being said, if someone is concerned about their health enough to use an app like this, they SHOULD be eating at home more. They only way to know what is in your food is to make it yourself.
The high level goals are to increase protein, increase fiber and decrease sugar. Super simple. Tracking takes <5 minutes per week, for the entire family. With the receipt it recommends foods to buy more or buy less to help the user hit their protein, fiber and (low) sugar goals.
I used no-code Appgyver and have been very disappointed in its robustness. The backend is all hooked up. Everything works, but I've learned I'm not good at marketing. There many better (and free) sources of information to obtain nutrition data.