Portable health: real nutrition you can pocket.

In their early years, meal replacement bars and drinks were designed to fit in the back pockets of long-distance cyclists and runners. Today, these nutrition-packed foods are just as likely to be tucked away in the glove compartments of busy motorists for healthful, quick meals.

With sales for nutrition bars and drinks increasing by more than 20 percent per year, new flavors, such as pecan pie and chocolate caramel, mean you don't have to give up taste for convenience in the bar category. And drinks are no longer limited to only chocolate and vanilla; instead, look for shakes in tropical and berry fruit flavors.

Insoluble and soluble fiber are common ingredients for bars and drinks. As researchers learn more about fiber's role in immune function, digestive health, and cholesterol and blood sugar levels, meal replacement bars and drinks are being introduced that contain disease-fighting fibrous substances derived from oats, flax, quinoa, chicory tool, fruits and vegetables. Nutrient boosters such as echinacea, ginkgo and probiotics, which are commonly found on smoothie bar menus, are also finding their way into meal replacement products. Some contain ingredients found only in dietary supplements, and therefore are sold as such. For this reason, read the labels carefully, especially before offering bars and shakes to children.

The number of choices are so vast that selecting the right one for the right purpose--whether for weight loss, athletic performance or just a healthful snack--can be daunting. The trick is to know which ones fit your specific needs.

Nutrients

Meal replacement products may look like candy bars and milk shakes, but they're actually a unique delivery system for nutrients--proteins, fats, carbohydrates, vitamins and minerals. When eaten periodically, they offer a healthful alternative when a conventional meal isn't available, says Susan Kundrat, RD, a dietitian at the University of Illinois and Strawberry Fields Natural Food Store in Urbana-Champaign, Illinois.

Many people don't think about how nutritionally dense these products are. For instance, one meal replacement bar or drink may contain anywhere from 35 percent to 100 percent of the recommended daily intakes (RDI) of vitamins and minerals. If you eat a bar in addition to taking a daily multivitamin, you may exceed the RDI's for some vitamins and minerals, such as vitamin …