Your personal trainer subsists on whey shakes, your sister's sworn off dairy, and a book you picked up on barnesandnoble.com recommends watercress soup for weight loss.
Is it any wonder you're stymied about what to eat come mealtime?
To ease the confusion, we rounded up top nutrition and weight-loss experts to answer the most burning questions.
Fruit juices, coffee drinks and regular soda are liquid calories that don't yield much satiety, says Willett.
"Cravings are a normal and natural response to underfeeding yourself and can be prevented simply by planning and eating enough throughout the day," says Katherine Tallmadge, author of "Diet Simple" (Lifeline Press, 2002).
If the craving lingers after making this alteration, it may be emotionally based.
One slice of Pizza Hut's Pan Pizza with Italian sausage packs 320 calories with 20 grams of fat; Burger King's Double Whopper with Cheese serves up 1,070 calories and 70 grams of fat.
In the cafeteria line at work, you can make healthy choices, says Tanya Bridges, a clinical dietitian at the University of Michigan Health System in Ann Arbor.
"Because I'm a dietitian, people are constantly looking at my tray as I go through the line," she says with a laugh.
Taking in more than 3,000 milligrams daily may interfere with calcium absorption, which can weaken bones over time.
And according to the National Heart, Lung and Blood Institute, most women consume 15 to 40 percent more than the recommended 2,400 milligrams of sodium per day (the equivalent of about 1 teaspoon of table salt).
High-energy dense foods, those that have a low fiber or water content, take up relatively little stomach space, so you may find yourself consuming greater quantities," says Dr. Cheskin.