It’s always better to eat healthful, nutrient-packed foods—fruits and veggies, low-fat dairy foods and lean protein sources, such as poultry and fish—but when it comes to weight loss, a calorie is a calorie is a calorie. Accumulate 3,500 extra ones and you gain 1 pound. That’s why it’s so important to learn what a portion really looks like (hint: a serving of lean protein should not be as big as your head). Mastering the principles of healthful cooking can help you make dishes that deliver “deliciousness” without all the calories and fat. The result: You won’t feel deprived and fall off the wagon with a big binge when your co-worker brings in a plate of her homemade brownies to share.