I've thought about making something like this in the past. I've used the "Nutrients" iOS app for tracking nutrition, but not in the way it's meant to be used. Maybe my usage patterns could help you writing your app. I tend to use the app to get a pulse on the nutrient density of the foods I consume (or feed my daughter). I would make simple meals, and plug them in, and then try to get all the nutrient bars filled up.…
I would also suggest avoiding leafy vegetables in general, since there are a lot of defensive chemicals in them that are not very good for you, especially concentrated blended versions of them. You tend to want to eat plants in states that they want to be eaten in, such as fruit flesh. Plants don't want their leaves and seeds to be eaten, thus the large amount of protective chemicals in them to discourage that from happening. The ideal situation for plants is you eat a fruit when it's ripe, swallow the seed whole, and pass the seed in your stool somewhere else in a stool fertilizer bed on the ground somewhere. This means low sugar fruits that we call vegetables like cucumbers and tomatoes are also ok.
Also fish and liquid oils tend to go rancid fairly fast. Solid oils tend to stay fresh longer. If you want more fish in your diet, eating actual fresh wild fish vs a fish oil significantly healthier.