Development of application design

There is a program for counting calories eaten in the form of a mobile application. The essence of the program - in the application is a database of the most popular products and drinks. There are both individual ingredients, such as onions, potatoes, tomatoes, and ready-made dishes, such as French fries, Greek salad, etc. After the user enters his data, information is given on what exercises he should do in the near future to maintain the figure, as well as general recommendations from the nutritionist. This is short to make it clear what I mean.
The software part is ready, and the design of the application is also there, but the design is very primitive.
So, you need a designer who will develop a colorful design for the application under the above topics.