Skip to content

What Happens to Your Body When You Eat a Subway Footlong

There are both positives and negatives to ordering this "healthy" fast-food item.
FACT CHECKED BY Olivia Tarantino

With those catchy jingles and convenient locations, you will be hard-pressed to find a soul who has never heard of Subway Subs.

Home of the footlong, Subway is a fast food joint that offers up a variety of options, including sandwiches, salads, drinks, and some of the best cookies on earth (in my humble opinion).

When ordering a submarine sandwich (or a hoagie/grinder depending on which neck of the woods you come from), many people opt for a foot-long option: a sandwich made on 12-inch bread. From there, they can pick the type of bread, protein choices, fresh veggies, and condiments that will be added to make a very own personalized creation.

And while scarfing down a footlong sub can be utterly satisfying, eating one can come with some side effects, too.

Here are six things that may happen to your body when you eat a Subway Footlong Sub. Read on, and for more on how to eat healthy, don't miss Every Subway Sandwich—Ranked for Nutrition!

You may lose weight.


If you are opting for lower-calorie subs like a foot-long veggie option with lower-calorie condiments, you may end up losing weight. Choosing a Footlong Veggie Delite sub on 9-grain wheat bread, veggies, and no cheese or condiments is a meal that is under 400 calories and only contains 1 gram of saturated fat. This is a far cry from the over 1,000 calories that a McDonald's Big Mac and fries contain. So, opting for a sub like a Footlong Veggie Delite can save you around 600 calories if you are swapping that lunch out from a typical "fast-food burger-and-fries" meal. If you're more of a burger purist, at least opt for one of these 13 Healthiest Fast Food Burgers, Recommended By Nutritionists.

You may gain weight.

subway vegetable sandwich on honey oat bread
Prachana Thong-on/Shutterstock

And on the other end of the spectrum, if you are choosing high-fat and high-calorie sub options, you may experience weight gain. While there are some lower-calorie footlong menu items, choosing an option like the Chicken and Bacon Ranch sub will set you back over 1,000 calories and 51 grams of fat. Tack on a side of chips and a regular soda, and you could potentially take in all of the recommended calories that you need in a day in one sitting.

Opting for a 6-inch sub will cut your calorie and fat intake literally in half. And limiting more caloric additions like cheese, bacon, mayonnaise, and ranch dressing can help you enjoy your subs without packing on the pounds.

Sign up for our newsletter to get daily recipes and food news in your inbox!

You may have an increased risk of high blood pressure, heart disease, and stroke.

Subway sandwich artist making sub
Prachana Thong-on/Shutterstock

"Subway does offer some healthier options, but many of their footlong subs are quite high in sodium," nutritionist Sarah Garone, NDTR explains.

"The Turkey & Bacon Guacamole, for example, has 2,300 mg of sodium—the amount recommended for an entire day! In the long term, consistently eating a high-sodium diet can increase your risk for issues like high blood pressure, heart disease, and stroke. People who already have these conditions should be especially careful about their sodium intake. For a healthier, lower-sodium choice at Subway, I'd recommend the Tuna or Veggie Delight subs." Add these sodium-rich subs to the list of 13 Worst Foods for High Blood Pressure.

You may have a blood sugar spike.

closeup of subway subs with drinks

The amount of carbs in a footlong sub made on 9-grain wheat bread can range from 76-104 grams, or around what is considered to be 5-6 servings of carbs. Eating this many carbs may cause your blood sugar to skyrocket, especially if the sub is being washed down with a sugary soda or sweet tea.

When eating a sub, making sure that you are including ample amounts of protein and healthy fats can help lower the glycemic load of the meal, and therefore help manage blood sugars. Including lean meats and fat sources like olives and olive oil are all blood sugar-friendly ingredients that can help keep your blood glucose in check.

You can have healthy bowel movements.

subway sandwich

It is recommended that most adults take in approximately 28 grams of fiber every day. And if all of the fresh veggies are served on the sub and the bread selected is the 9-grain wheat variety, many footlong subs will provide 10 grams of fiber or around 40% of the recommended intake. Eating a footlong sub brings you almost halfway to your goal for the day! For more ways to increase your fiber intake, try these 20 Different Ways to Eat 28 Grams of Fiber a Day.

You may feel bloated or nauseated.


If eating a footlong sub is more food than what your body is used to eating in one sitting, you may feel bloated, nauseous, and even heartburn due to overeating. For some people, eating something that is the size of a literal foot can be way too much for their tummy to handle. Plus certain varieties of the subs — like the Italian B.M.T. — can contain upwards of 2,000 milligrams of sodium. Eating too much sodium at one time can make your entire body feel bloated, including your fingers and toes!

If you do feel these unsavory symptoms, try going for a walk or sipping on some ginger tea to hopefully offer some relief. And if your rings start to feel snug on your fingers, try drinking some water to help balance your bloat. Speaking of being bloated, sodium isn't the only cause of a distended belly. See: The Most Common Reason You're Always Bloated, Say Dietitians.

Lauren Manaker MS, RDN, LD, CLEC
Lauren Manaker is an award-winning registered dietitian, book author, and recipe developer who has been in practice for almost 20 years. Read more about Lauren