Don't assume that anything with the word "salad" in it must be healthy. Prepared tuna salads, chicken salads, and shrimp salads are often loaded with hidden fats and calories due to their high mayonnaise content. While a lot depends on portion size and ingredients, an over-stuffed tuna sandwich can contain as many as 700 calories and 40 grams of fat. If you're ordering out, opt for prepared salads made with low-fat mayonnaise, and keep the portion to about the size of a deck of cards. Better yet, make your own, like this Herbed Greek Chicken Salad.