Nutritional science and food marketing has become so sophisticated in recent decades that a trip to the supermarket can require a complete nutritional re-education. The average consumer needs to be on guard against preservatives, added fat, colorings, and calories, false advertising, and sophisticated but misleading labels. Although guidelines for the information of food labels have gotten a bad rap in recent years, a new study suggests that observing them may lead to weight loss, especially for women entering their middle years.