Book excerpt: Mavis Jukes is here to help girls learn how to be healthy so they can stay healthy. In this newly updated edition, Jukes and co-author Lilian Cheung, D.Sc., R.D. target what girls need to know in order to achieve an active lifestyle and how to avoid the pitfalls of body image issues. Readers will find basic nutritional information; ideas for safe exercising; tips on how to eat right no matter where they are; and lots of other kid-specific information on food, fitness and feeling great. From the Trade Paperback edition.