"PupDiet" is an awesome app with a lot of info with tips and tricks about food for dogs.

CHOOSING THE RIGHT DIET

[+] Commercial dog food
This app will show you what ingredients you need to look for in dog food and what ingredients you should stay away from. It will also help you decide what type of dog food be it soft, semi-moist, or dry dog food, is best for your dog.

[+] Hints for Common Problems
This book will also show you how to handle your dog's stomach issues and waste issues. What to do if your dog's stomach is acting up and when and if you should call your vet.

Here is what you will learn inside this guide:

1) When you should start a good diet for your dog?
2) What is the raw food diet?
3) Does your dog's diet affect its waste?
4) What to look for in good dog food and where to find them?
5) Why you should not give your dog table scraps?
6) The debate on rawhides
7) What kind of diet your senior dog might need?
8) How much extra food your pregnant dog really does need?
9) Does your dog need vitamins?
10) And most importantly, why your dog needs a good diet?