The McDonald's Filet-o-Fish sandwich consists of a square, breaded white fish filet -- usually Atlantic Pollock -- topped by tartar sauce and American cheese served on a hamburger roll. This sandwich originated in St. Louis in the 1960s with a McDonald's franchise owner in a heavily Catholic location who was looking for a way to boost sales on Fridays, a day when Catholics traditionally eschew meat. While the Filet-o-Fish is quite high in fat and calories, it contains a wealth of vitamins and minerals.
Calories and Fat
A serving of Filet-o-Fish – one sandwich – has 400 calories, representing 20 percent of the calories you may include in your daily meal plan if you adhere to a 2,000-calorie diet. Your daily calorie requirements vary depending on your height, weight and other factors; consult your physician for advice. Nearly half the calories of a Filet-o-Fish come from fat, the 20.5 g of fat per serving can eat up almost one-half to one-third of your allotted fat – 44 to 78 g per day.
Carbohydrates and Protein
One Filet-o-Fish contains 40.3 g of carbohydrates and 14.8 g of protein. The Institute of Medicine recommends including 130 g of carbs and 46 to 56 g of protein in your meal plan each day. These macronutrients both serve as a source of energy for your body, but they have other functions as well. The protein in a Filet-o-Fish helps you build muscle and make important hormones and enzymes, and carbohydrates can play a role in your digestive and bowel health.
Vitamins and Minerals
A serving of Filet-o-Fish serves as a good source of thiamin, or vitamin B-1, delivering 24 percent of the daily recommended intake. This vitamin maintains the function of your nervous system, heart and muscles, and, like all B vitamins, it aids in converting carbs to energy your body can use. One sandwich also provides 17 percent of the vitamin B-12, niacin and phosphorus you require daily, as well as 16 percent of the suggested daily value of calcium.
Along with having a high amount of fat, a Filet-o-Fish sandwich contains quite a bit of sodium. Each sandwich has 633.1 g, more than one-third of the recommended daily limit of 1,500 mg. Limit your consumption of sodium whenever possible as too much in your diet can increase chances of developing high blood pressure, putting you at risk of heart attack and stroke.
All fish contains mercury, but Pollock contains a very low level of this potentially dangerous contaminant. In addition, eating a Filet-o-Fish gives you omega-3 fatty acids, a compound that offers benefits for your brain and heart.