Insulin Resistance Diet: What Runners Should Know

Runners with insulin resistance face a unique challenge: On the one hand, they’re told to watch how many carbs they eat in order to keep their blood sugar levels from getting out of hand. On the flip side, runners need carbs to fuel their workouts.

So, what’s a runner to do and what constitutes an insulin resistance diet for runners?

“A runner with insulin resistance will need to be more intentional with their food choices and planning their meals and snacks in order to manage their blood sugar levels,” says Kristy Baumann, RD, a dietitian and marathon runner based in Minnesota.

This guide to an insulin resistance diet for runners can help you navigate the balance between carb intake and maintaining healthy blood sugar.

What It Means to Be Insulin Resistant

According to the Centers for Disease Control, insulin resistance occurs when cells stop responding to the hormone insulin, which regulates blood sugar. If this happens, too much blood sugar enters the bloodstream and the pancreas produces more insulin to help get blood sugar out of the blood and into cells.

If this process continues over time, the cells become more insulin resistant and blood sugar in the bloodstream rises more consistently. This can lead to weight gain, and also to prediabetes and diabetes, both of which have serious health implications, such as cardiovascular and neurodegenerative diseases. According to the National Institutes of Health, prediabetes usually occurs in people who already have some insulin resistance.

Two proven ways to fight insulin resistance and, therefore, high blood sugar, are diet and exercise. In 2022, the journal Nutrients published a special issue called “Impact of Diet Composition on Insulin Resistance.” Researchers noted that while high sugar intake is associated with insulin resistance, the advice to eat low-carb in response is not necessarily the best approach. In fact, plant-based diets, which tend to be high in complex carbs—such as vegetables and whole grains—rather than high-protein diets “result in lower insulin resistance and a lower risk of prediabetes and type 2 diabetes.”

Fortunately for runners, research also shows that running and exercise, in general, can improve insulin resistance.

Here, Baumann and other sports dietitians outline the advice they share with their running clients who have insulin resistance.

The Benefits of Complex Carbs for Insulin Resistance

You don’t need to avoid carbohydrates if you have insulin resistance. In fact, carbs are a must-have, especially for runners. “As a runner, carbohydrates are your body’s preferred source of energy for your brain and muscles,” Baumann says.

The key is to choose complex carbohydrates over simple ones as often as possible. As the American Diabetes Association (ADA) explains, we digest complex carbohydrates slower than simple or refined carbs, so they’re less likely to spike your blood sugar.

Complex carbs include fiber-rich foods such as quinoa, brown rice, wheat berries, and whole-wheat and lentil-based pasta. Simple carbs include refined grains, including white bread, rice, fruit juice, and sweets, such as candy and cookies.

“If we’re intentional about choosing more complex carbohydrates that have fiber, that is really going to help us get the carbs we need as runners, without throwing off our insulin and blood sugar response,” says Meghann Featherstun, RD, a sports dietitian and runner based in Cleveland.

That said, because we’re all different sizes and have different activity levels, there’s no ideal amount of carbs for someone with insulin resistance. “I have some clients who do okay on the lower end of the carb recommendations, which for athletes is around 45 percent of your daily calories, and other people do fine at the higher end, which is up to 70 percent of calories coming from carbohydrates,” notes Holley Samuel, RD, a board-certified specialist in sports dietetics and runner who lives in Durham, New Hampshire.

Samuel recommends starting somewhere in the middle (between 55 and 60 percent of your total daily calories) and adjusting up or down depending on how you feel. For example, if you notice that you feel fatigued even when your sleep is solid, struggle to sleep, or don’t have the energy to get through your runs for a couple of weeks, try bumping up your carbs. But if you still feel this way after several weeks, and your bloodwork shows that your A1C (your average blood sugar levels) are increasing, you may need to consider whether you’re including adequate fat and protein with your carbs.

“For endurance athletes, it’s quite rare that I recommend lowering carbohydrate intake, even with insulin resistance,” Samuel notes.

Why You Need Fat and Protein if You’re Insulin Resistant

In addition to complex carbs, you also want to make sure you’re eating enough fat and protein. Eating the right amounts of these macronutrients helps control your blood sugar response, too.

“Pairing carbohydrates with fat and protein slows digestion and absorption so it’s more like a trickle of carbohydrates into your bloodstream, and that’s easier for a body with insulin resistance to deal with versus flooding it with carbohydrates and there’s nothing to slow it down,” Samuel explains.

Again, exact servings will vary, but the ADA’s plate method, designed specifically for those with diabetes, offers a good guideline: Fill half your plate with nonstarchy vegetables (e.g., broccoli, cabbage, cucumber, leafy greens, peppers), one-fourth with lean protein (e.g., salmon, tuna, sirloin, nuts, tofu, chicken), and one-fourth with a grain or starch (e.g., brown rice, polenta, whole-grain pasta, potatoes, beans, sweet potato). Add a piece of fruit or a small glass of milk if you’d like.

How Simple Carbs Can Be Fuel for Insulin Resistant Runners

Most of the time, complex carbs are the way to go. However, fueling strategies for your run don’t change if you have insulin resistance, which means that 30 to 60 minutes before a run, you can go for a quick-digesting carb such as a mini bagel, a slice of toast with jam, a gel, or a couple of graham crackers.

If your run is short (60 minutes or less) you need roughly 30 to 60 grams of carbs before you head out. If your run is longer than one hour, but less than two hours, you may need to refuel with another 30 to 60 grams of carbs along the way. And if your run is more than two hours long, you might consider restocking with 60 to 120 grams of carbs per hour, Samuel says.

“How the body processes carbohydrates while we’re running is a little different from how it does at rest, and the difference is that muscles can uptake glucose out of the bloodstream without insulin being required,” Samuel says. Translation: Your body uses the sugar from simple carbs to fuel your running, so you don’t get the same spike in blood sugar if you eat simple carbs as you would otherwise.

Some other examples of good prerun snacks include: an applesauce pouch, 1 cup of cereal, 1 cup of juice, or a combination of these, Samuel says.

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A 1-Day Sample Insulin Resistance Diet Plan

Baumann crafted this one-day meal plan for runners with insulin resistance. Use it as a springboard for creating your own meals, keeping in mind that your calorie and carb needs may be different.

🥑 Breakfast

Avocado toast:

Side of 1 to 2 hard-boiled eggs (0.5-1 grams carb)

🍌 One hour before-a-run snack

1 banana (27 grams carb) with 1 Tbsp of nut butter (4 grams carb)
1 cup of low-fat milk (13 grams carb)

OR

1 English muffin with 1 Tbsp of honey (43 grams carb)
1 hard-boiled egg (0.5 grams carb)

🥪 Post-run snack

1 cup of low-fat chocolate milk (24 grams carb)

OR

Turkey sandwich:

🥙 Lunch

Grain bowl:

🫐 Snack

Yogurt parfait:

🍠 Dinner

Sweet potato and salmon sheet pan meal:

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How a Food Journal Can Help Runners With Insulin Resistance

Tracking your food and symptoms can be a great short-term tool to figure out the appropriate amount and type of carbs that work for you personally as you learn to manage insulin resistance while fueling your workouts.

You can use a food tracking app such as LoseIt or MyFitnessPal, but Featherstun prefers a simpler method, including pen and paper, a Google Doc, or the Notes app on your phone. “That way, we’re not tracking numbers, we’re just tracking what we ate, when we ate, and how we felt. I try to encourage people to look at those types of things versus micromanaging calories, which can be a slippery slope,” Featherstun explains.

If calorie-counting apps stress you out, note your energy levels, how you feel during your runs, and any muscle pains or injuries that crop up instead of focusing on numbers. You’ll know you’re on the right track if your energy levels are even throughout the day, your running performance continues to improve, and you’re free of chronic pain and injury. On the other hand, if you struggle with any of these markers for at least two weeks, “then something’s up,” Featherstun says.

Try bumping up your carbs a bit and see if you feel better. “Most of my clients who have insulin resistance are underfueling, so we add food and carbohydrates and their insulin response typically improves,” Samuel says. Usually, runners who are underfueling aren’t eating enough before or after their runs, so try adding carbs to your prerun snack and postrun meal and make sure you’re eating enough throughout the day, too.