A snack has one job: bridge the gap so you arrive at your next meal hungry but not desperate. Almost every snack that fails does so for the same reason — it was all carbohydrate, so it raised your blood sugar, dropped it, and left you hungrier than before.
Build every snack around a protein anchor, then add one whole food if you want it. Greek yogurt and berries. Cottage cheese and cucumber. A hard-boiled egg and an apple. Jerky and grapes. Cheese and a pear. Edamame with a little salt.
Bars and shakes are food, not cheating — useful in a bag, in a car, in an airport. Read them like food: 15–20 grams of protein, fibre present, sugar not the first ingredient.
If you're not hungry at a snack slot, you don't have to eat it. Mark it skipped in the app and it re-sizes the rest of your day so the protein still lands.