Sponsored by our partner, Viome

News flash: what you eat—even the healthiest meals with the best of intentions—may not be serving you. We talk about complex carbs, proteins, healthy fats and micronutrients often. But what we don't talk about enough is how they impact your microbiome (a.k.a. your gut health and GI tract)—especially when it comes to blood sugar spikes and crashes, and how that impacts performance.

Our gut is responsible for many functions, from breaking down food and converting it to usable energy, to producing hormones necessary for sleep and performance. Our microbiomes are also as unique as we are (only 1% crossover from person to person). This means eating for your individual gut signature is essential for optimal performance. 

Because our guts' needs are so specific, according to fresh science, this actually makes the food pyramid and glycemic index chart things of the past. (Telling everyone to eat the same way is as good as telling every Spartan they should be on the same training plan... it just wouldn't work. Bodies are different and respond differently to fitness stimuli.) 

So let's look at how eating different foods can impact blood sugar levels and therefore performance. And why it's so crucial to know your own gut health parameters to optimize your nutrition plan for you. Because, seriously, the last thing you want is to hit a fatigue wall in OCR training.

Related: Test Your Gut IQ to Maximize Your Nutrition Plan (+ Performance)

Why "Healthy Eating" Doesn't Necessarily Equate to Optimal Eating

Let's say sweet potatoes don't sit well with your gut. You know from the food pyramid that they're healthier than most starches, but you're not aware that your microbiome responds poorly to them. You chow down and your blood sugar spikes, your gut produces an inflammatory response and your performance plummets in the come-down crash. 

It's the sugar in sweet potatoes that you have an aversion to in your microbiome, which caused the glycemic spike. Whereas the Spartan next to you eats sweet potatoes, his gut is cool with it and he performs like a rockstar. In short, while you think you're eating healthy, until you know what your microbiome signature is, you may be throwing your body out of whack and negatively impacting your performance. Your energy levels can't meet the demands of your fitness regimen.  

Blood Sugar Study: The Science

How a particular food impacts your body (i.e. spiking blood sugar, storing as fat, causing water retention, etc.) is heavily based on the function of your microbiome. And with regards to energy levels, especially impacted by the sweet stuff, it's time to reframe how we think about individual foods and blood sugar. 

In 2018, Viome did a study on glycemic response. 550 participants wore a continuous glucose monitor for two weeks to measure their blood sugar levels. Each participant ate the same meals (27,000 collectively, to be exact) from Whole Foods Market. During data collection, Viome sequenced the participants' microbiomes to monitor function and response to various foods, building a predictive model to forecast blood sugar response based on each participant's unique microbial activity.

The findings? The impact of a particular food on a person's blood sugar is heavily dependent on the function and activity of their microbiome.

A Quick Case Study

For example, let's compare User 101 and User 472 who were both given a banana. User 101 had a massive blood sugar spike after eating it, while User 472 had almost no blood sugar response. Conversely, when both users ate a slice of whole-grain bread, each had the complete opposite blood sugar response. 

The Bottom Line: Optimize What You Eat to Perform Your Best 

This study proved blood sugar response is heavily dependent on the specific person's unique microbial activity. 

Why does this matter? Because if you want to maintain stable energy levels during a workout or race (or heck, even during the workday), you need to know which foods will cause you to spike and crash, and which will give you sustainable energy.

Most athletes know that eating cake and ice cream before a training session will lead to a sugar crash (and maybe even make you puke). But what about quinoa or wild rice—two "healthy" food options? 

The good news? There's a solution. Test your gut with Viome by taking a few at-home stool samples, sending them to the lab and voila, you'll get a personalized, precise list of food recommendations on what to eat for your gut—and what to avoid like the plague.