Build an App

I am looking to have my paper food journal turned into an app that customers can use to log their daily food, water & exercise. I would like my nutritionists to be able to view the content in our online record keeping platform, or in a password-protected portion of our website. Customers would enter data 3-5 times per day, and the nutritionist will view it 1x or more per week. It does not need to have pretty graphics, just the ability to track food, water & exercise. It does not need to track calories.