Endurance athletes like obstacle course racers rely heavily on carbs to fuel outstanding performances every weekend across the country and the world. While most seasoned athletes recognize this need for quality carbs, not every type of athlete requires such a heavy focus on this one macronutrient. That's why it can become easy to fall into a low-carb fueling trap when trying to eat "healthy" — especially as a hybrid athlete, such as a DEKA competitor. 

The term “sourfaux bread” might at first sound like a good thing; some valiant sourdough bread substitute free from the gluten or carbohydrates you may try to avoid. But alternatives marketed as "healthier" options of your favorite foods can secretly contain some other ingredients you might be better off avoiding — especially if you have certain food sensitivities or digestive issues.

Related: 7 Plant-Based, Healthier Versions of Your Favorite Comfort Foods

When it comes to certain foods — carbs in particular — sometimes you're better off opting for the real deal. We asked experts for a rundown on sourdough and its low-carb alternative, so you can pick the bread that best supports your health and your athletic goals the next time you do stop into that bakery.

Sourdough vs. Sourfaux: What’s the Difference?

Traditional sourdough bread is made with just three ingredients: flour, water, and salt.

First, bakers combine the flour and water to create what’s known as a leavening agent (or “culture” or “starter”), which helps the dough ferment and rise. While other breads use commercial yeast to make the dough rise, sourdough skips it. 

“To start a sourdough bread culture, you mix flour and water together and leave it on the counter for up to a week to ferment, and it absorbs the bacteria and yeast from the environment,” Esther (Essie) Schultz, founder of the Good Grain Bread Company (a micro-bakery dedicated to sourdoughs), says. “It goes through this long, incredible process of breaking down the grain.”

“Sourfaux” bread, meanwhile, refers to bread labeled or advertised as “sourdough,” but made with ingredients beyond the traditional three. This includes not only commercial yeast, but things like ascorbic acid, yogurt, and vinegar, too. 

Related: Why Eating Whole Grains Can Make You Feel Better Mentally and Physically

The appeal of this knock-off sourdough bread?

“Bread rises faster with commercial yeast,” Schultz says. “You can go from dough to loaf within a few hours.”  

Of course, this reduced prep time is pretty darn enticing to large grocery store chains and fast food restaurants that sell bread in bulk. The result? Many pass off “sourfaux” as the real deal. 

But why does a little yeast and a few extra ingredients in your bread really matter? While the price tag on a loaf of mass-produced “sourfaux” may be lower than that on a traditional, artisanal bakery loaf, you get what you pay for. Here's exactly why real sourdough is your best bet. 

5 Reasons to Eat Real Sourdough Bread

1. It’s easier to digest.

The proofing (final rising) process of naturally-leavened bread, like sourdough, takes several days. It’s during that extended fermentation that the magic happens, Kayleen St. John, M.S., R.D., adjunct professor of nutrition and food studies at New York University, says. 

Related: Why Endurance Athletes Should Care About Probiotics

“A pre-digestion occurs, meaning the yeast and bacteria start to break down some of the chemical bonds in the flour’s starches,” St. John explains. “This makes it easier for our stomach to digest because the bacteria already did the work for us on the kitchen counter.”

2. It offers more nutritional value.

Sourdough’s longer fermentation process also breaks down the phytic acids in the flour. Known as anti-nutrients, these phytic acids can block our absorption of certain nutrients, like minerals and B vitamins. So, eat traditional sourdough bread and you’ll get more nutritional bang for your bite.

3. It’s less likely to leave you bloated or gassy.

Though our bodies struggle to digest fiber, our gut bacteria thrive on it. 

The issue is, as these helpful gut bugs ferment the carbs we can’t break down, they produce gasses like hydrogen, carbon dioxide, and methane — all of which contribute to bloat and flatulence. 

“However, with naturally-leavened bread, less fermentation happens in your gut because it’s already happened before the bread entered your body,” St. John says.

Related: This Is How Leaky Gut Syndrome Directly Affects Your Workouts

While we’d all like to avoid gas and bloating when possible, this is especially helpful for people with irritable bowel syndrome (IBS) or sensitivities to FODMAPs. (FODMAPs are certain types of carbs that are poorly digested in the small intestine, and thus cause gas, bloating, stomach pain, diarrhea, and constipation.) 

For these people, “a sourdough bread made with whole-grain flour is a way to get fiber that might be lacking in gluten-free products and rice into their diet,” St. John explains. 

4. It’s free of preservatives and other sketchy ingredients.

Commercially-prepared breads — sourfauxs included — tend to contain stabilizers and other additives that extend their shelf life, St. John points out. If you’re trying to avoid additives and preservatives (either on principle or due to sensitivities), consider this just another reason to opt for traditional sourdough bread.

5. It tastes better.

“Real sourdough has a more complex flavor, plus each loaf is unique to the baker’s environment,” Schultz says. “If I brought back a culture of some famous sourdough from San Francisco, it would eventually adapt to my environment because of the different ambient bacteria and yeast.”  

How to Determine Which Sourdough to Buy at the Grocery Store

So, how can you tell if the loaf you’re eyeing at the store is an original or knockoff? 

For starters, always read the label and scan the ingredients list.

“If you see a yeast as an additive, then you know it’s not a full-blown, naturally-leavened sourdough,” St. John says.

If you don't see a label, ask the baker. Another good indicator will be on the price tag.

“If I go to the market to get a real loaf of sourdough bread, I’m prepared to spend 12 dollars because I know it took them three days to make this bad boy,” St. John says.