Breadlike bagels are a dense versatile food. They can be eaten plain or made into a sandwich with fillings of cheese, hams, tuna or mayonnaise. Bagels themselves can be plain or in flavors such as garlic or onion.
Onion bagels have about 78 calories per ounce. So a bagel measuring 3 inches in diameter contains about 190 calories. A 4 1/2-inch onion bagel provides 360 calories.
Regular cream cheese has 35 calories per tablespoon and 3.5 g of fat. Low-fat varieties contain fewer calories -- about 23 calories each tablespoon and 1.8 g of fat.
The total calories in a large bagel with 3 tbsp. of regular cream cheese is 465 calories. If you opt for a small bagel weighing 2.4 oz. served with 2 tbsp. of low-fat cream cheese, you will consume 236 calories. Choose a whole wheat bagel and you will increase your fiber content, which can support weight loss because fiber-rich foods help to keep you feeling full.