Some frozen dinners are very high in fat. Because fat contains twice the number of calories compared to carbohydrates or protein, this often makes frozen dinners high in calories, by default. For example, a 1-cup serving of frozen chicken pot pie may contain nearly 600 calories, more than half of which come from fat. Each pie is 2 cups, so eating the whole thing will net you about 1,200 calories and more fat than many people need in an entire day. No more than 20 percent to 35 percent of your total calories should come from fat, according to the publication, "Dietary Guidelines for Americans, 2010.