Like other small dogs, shih tzus grow up quickly, so they need plenty to eat during those early months. While yours should have puppy food during her growing stages, that type of food has high calories that can fatten her up fast once she's fully grown.
Choose a high-quality dog food. While you can get relatively inexpensive brands, they aren't necessarily good for your puppy -- it would be like giving a baby fast food for every meal. Shih tzus in particular need organs like liver and heart, along with fish, vegetables, starches and lean meats like chicken and lamb. Read your dog food labels carefully to make sure that they have ingredients like these -- meat should always be first.
Measure out her food on a daily basis according to the instructions on the package. Because foods are formulated with different ingredients, some don't require your puppy to eat as much. Using your puppy's age and weight as a guide, follow the instructions to determine how much she should eat each day.
Feed her on a schedule. For the first six months, she should eat about four times per day. After that, she should be down to two meals a day.
Consult your vet for regular checkups every few months. Your vet can tell you when your shih tzu is physically mature -- given her size, that will probably happen sometime around the one-year mark. This is the time when you should transition her into adult dog food, which has fewer calories -- she'll probably be eating about 1/2 to 1 cup of dry food every day.
Tom Ryan is a freelance writer, editor and English tutor. He graduated from the University of Pittsburgh with a degree in English writing, and has also worked as an arts and entertainment reporter with "The Pitt News" and a public relations and advertising copywriter with the Carnegie Library of Pittsburgh.