Worried about how many calories you are going to consume in that slice of pizza, chocolate cake or bag of fries? A new iPhone application may help. After taking a picture of the meal with the phone, the app gives a calorie read-out almost instantly. Within seconds of taking a picture of a meal and matching it to a database of some 500,000 food items, MealSnap sends users an alert with a range of calories for the meal that was photographed, making it easier to track the calories in food. MealSnap also serves as a food diary, allowing users to keep a visual log of the meals they have eaten. Just take a picture. MealSnap is available at the iTunes store.