Theres no reason to go hungry or wreck your diet when youre traveling or stuck in a hotel room without room service. Take along these healthy snacks suggested by Charles Stuart Platkin, nutrition and public-health advocate, and author of The Diet Detectives Count Down.

Cereal in a cup. Great for portion control at 1.5 ounces; choose one with less than 120 calories per ounce.

Tuna or salmon. Get them in convenient peel-and-eat cups.

Nuts. Portion this excellent protein source into 1-ounce bags for about 160 calories.

Fruit. Grapes and apples travel easiest.

Energy bars. Although they can be high in fat and calories, they still beat a slice of pizza or a candy bar at the airport.

Nonfat yogurt. Pack a 3-ounce container in an insulated bag.

Sandwiches. Try chicken or turkey cold cuts and cheese on whole-wheat bread; precut them into portion-controlled sections so you can snack throughout your trip without making a mess.

Dried fruit. Eat it in moderation; its high in calories.

Note: Be sure to check with the Transportation Security Administration for the latest in-flight rules on taking food through security.