Eating for Energy: Racing to the Perfect Mid-Workout Refuel

By Emily Wei, November 17, 2021


Pre- and post-workout nutrition are crucial to performance, but when does the body require a mid-workout boost? How do you know when your glycogen stores will adequately fuel your exercise? And what should you be eating in the middle of a race? While it may take some experimentation to find your refueling bliss, the proper mid-exercise refuel can help you to achieve peak performance.


Remember that your refuel should be geared not only towards your workout, but also to achieving the proper balance of nutrients. The best way of figuring out where you stand and what your body needs is through a blood test. The InsideTracker Performance Plan measures 20 biomarkers essential for anyone who wants to optimize their performance, and can help you to achieve both your dietary and fitness goals. Refueling Basics

In reality, whether or not you need a mid-workout snack depends on both the length and intensity of exercise. A snack is beneficial in longer, more cardiovascularly-intense workouts, but may be counterproductive in shorter, less-aerobic exercise. For example, fueling up mid-workout is generally beneficial in runs longer than an hour, but unnecessary for a leisurely 3 hour stroll or 30 minute jog. 

Click here to see how InsideTracker can provide you with personalized food recommendations to help you achieve optimal performance!

Weightlifting: If you fuel properly beforehand, there’s no need for a mid-workout snack when pumping iron. Skip the Gatorade and stick to water. Cardio lasting less than an hour: If you’ve eaten properly throughout the day, you don’t need to eat or have a sports drink mid-workout. Be sure to stay hydrated by drinking water, especially if it’s hot and humid. (If you didn’t have the chance to adequately fuel ahead of time, grab a banana or peanut butter crackers, or have an easily digestible snack on hand.) Cardio lasting an hour or longer: Hey, endurance athletes: long-distance runners, cyclists, triathletes, cross-country skiers, I’m looking at you! Proper mid-workout refueling and hydration is absolutely essential in endurance activities. There’s usually no need to eat during the first hour of activity; your tank should already be full (from proper pre-workout nutrition). Glycogen stores will provide needed energy during this period. Runner’s World recommends aiming for about 30-60 grams (or 100-250 calories) of carbs per hour after the first 30 minutes of activity (such as in runs longer than 75 minutes). The Academy of Nutrition and Dietetics recommends consuming about 0.7 grams of carbs per kg of body weight per hour of endurance exercise. Example: If you’re 150 pounds (~68 kg), aim for about 48 g/carbs (=68x0.7) per hour. This is about 190 calories of carbs (48 g x 4 cal) per hour. A more general rule of thumb, as mentioned in Feed Zone Portables, is that for activities lasting more than 2 hours, eat at least half the calories you burn each hour. The intake you should aim for depends on your body size, intensity, and type of activity. An elite, 180 lb. athlete competing in an Ironman might require 250 calories/hour, while a 100 lb. individual running a 4 hour marathon may only need 100 calories/hour. Don’t Hit the Wall: During intense endurance workouts, your muscle glycogen can be depleted in as little as an hour. Once depleted, your body can only work at 50% of its maximal capacity. Your energy levels plummet and you feel extremely fatigued. Fortunately, proper mid-workout fueling can prevent you from bonking and keep you going strong.

Endurance Event? Time to Drink Up!

Hydration is essential, and particularly so during extended periods of strenuous physical activity. For cardio workouts over an hour, you can select either sports drinks or water.

Sports Drink or Water?

If you opt for a sports drink, adjust your food intake accordingly. Consuming 16-32 oz. of sports drink/hour will provide the 100-250 calories of carbs that you need each hour. If you skip the sports drink and choose water, be sure to also replenish electrolytes. You can add electrolyte or salt tablets to your water, keep a small Ziploc bag with salt on hand, or take an energy gel.

How Much?

Aim for about 1 cup (8 oz.) of water every 15 minutes during exercise. If it’s hot and humid, up your intake to 1.5 cups (12 oz.) every 15 minutes. Don’t consume more than 1 L (33.8 oz, or a little over 4 cups) per hour. Hyponatremia, or low blood sodium, occurs with excessive water and insufficient electrolyte intake. Individuals who sweat more profusely are also more prone to hyponatremia. Electrolyte replenishment is crucial!  Seriously, drink up. Endurance athletes are especially susceptible to water loss, and can easily lose over 1.5 L of liquid (or more!) during each hour of activity.

Get Your Snack On

When participating in an endurance event, your body is working extremely hard to keep you moving. After an hour of intense exercise, you’ve likely depleted your glycogen stores, and your body needs all the help it can get. Consume a high-carb, low-fiber, low-fat snack; your digestive system will thank you, and the food will quickly fuel your activity, increasing your stamina. Also consider the portability of a food, as well as how convenient it is for you to chow down mid-race. Furthermore, knowing your specific levels of key blood biomarkers, such as glucose, ferritin, and vitamin D, can help you target which nutrients you need to work on.

Below are some mid-workout eats for energy:

 A handful of pretzels ½ cup of dried fruit: think apricots, raisins, cranberries, kiwi, mango, and pineapple. Dried cherries, peaches, figs, and dates are higher in fiber, and may be harder to digest. This varies by individual however, and these fruits may be fine for some. Banana or orange slices Plain baked potato Cookies: animal crackers, graham crackers, Fig Newtons, or wafers. Many cookies are loaded with fat; choose a kind that’s low in fat for easier digestion. Jam or honey on white bread/bagel Energy gel or chew Fruit juice Sports drink A handful of the sweet stuff: jelly beans, Swedish fish, gummy bears, candy corn, peppermint patties, licorice, marshmallows, etc. You get the idea. Though candy hardly has the perfect nutritional profile, sugar provides quick, accessible fuel. Its powers can be harnessed for good during endurance exercise. Afraid of crashing? Fear not—when sugar is consumed during exercise, it only raises blood glucose and insulin slightly. Don’t over do it, though; consuming too much sugar in a short period of time (over 250 calories/hour) can cause GI distress. Get creative; you’re hardly limited to this list. A new cookbook of on-the-go food for athletes (Feed Zone Portables) goes outside the box. Think perfectly portable, homemade snacks, ranging from apple pecan sticky bites to BBQ chicken rice balls. (I think I’m ready for my first triathlon now!)

Are You Gellin’?

Energy gels and chews, composed of different blends of various sugars, are concentrated forms of carbohydrates. Gels and chews can provide rapid and much-needed fuel to athletes who require convenient and easily accessible fuel during long, intense workouts. It’s important to note that as alluring as these little packets of fuel may be, they’re not for everyone. Though gels and chews work well for many people, their concentrated form causes some individuals to experience upset stomachs. Additionally, the flavor and brand of the gel or chew can make or break its palatability. As with everything, experiment and tailor use during training so that you are ready to execute on race day.

Some Final Fuel For Thought:

Never try a new fueling routine on the day of a race; experiment while you are training. Adjust any mid-workout fueling to your individual needs, and always be mindful of how you feel. Can you tolerate specific foods during a run? (Stick to the ones that don’t make you nauseous.) How much food feels comfortable during exercise? (None? Grab a sports drink or juice.) Pay attention to how you feel, and always do what works best for you. If you stick with this, you’ll not only optimize your mid-workout nutrition, but also maximize your performance.

Remember that InsideTracker can tell you which biomarkers you need to improve, and give you ideas for foods that will both fuel your workout and help you reach your peak performance.


Try Our Free Demo

8 Ways to Biohack Your Health

Free eBook


New call-to-action