Based on your goals, the app recommends targets for red, yellow, and blue foods which help you stay satiated. At the same time not feel deprived of foods you like and that could be nutrient dense.
For weight gain, the daily distribution will tip more towards red and yellow foods as to avoid eating copious amounts of food through the day.
For Weight loss, the daily distribution will tip more towards yellow and blue foods to allow sufficient food amounts to last throughout the day
Knowing calories density allows a user to make smart choices about their daily foods. Specially when eating for a specific goal, calorie density can help map food choices.
For someone eating for fat loss, eating too many red foods can fill up their daily quota real quick leaving room for cravings. But blue and yellow foods might allow them to eat sufficiently throughout the day.