Tips for Avoiding the Bonk

For anyone who’s ever bonked during a workout, the feelings of dizziness, heavy legs and brain fog are all things you want to avoid at all costs! “Bonking” or “hitting the wall” are both commonly used terms to describe a sudden and sharp drop in mental and physical energy during exercise.

Running coach & exercise scientist Greg McMillan shares his tips on how to avoid bonking and how UCAN will help you maintain steady energy levels to finish your runs strong. Get 5 training & nutrition strategies to help you avoid the dreaded wall!

1. Keep Your Blood Sugar Stable

Your blood sugar levels determine your energy levels. When your blood sugar fluctuates, your energy does the same. If you have big swings in energy, you are much more likely to become fatigued during a sustained effort. Fueling with simple carbs like bananas, bagels & sports drinks or gels will cause a big initial spike in blood sugar, followed by a crash.

UCAN SuperStarch is a slow-releasing carb that keeps your blood sugar stable. Fueling with UCAN before a run helps you avoid the spike & the crash, provides long-lasting energy, and allows you to burn more fat. It’s the trifecta to avoid the bonk.


2. Happy Brain = Happy Body

If you have a significant drop in blood sugar, then your brain will not be happy and it will start to tell you that you can’t continue. This can be one of the causes of hitting the wall. If you can keep your brain happy so it doesn’t perceive your race pace for the race distance as a significant threat, it will help power your body along to the finish.


3. Become a Better Fat Burner

We all have exponentially more stored fat available as fuel compared to stored carbohydrate (glycogen). By restricting the intake of simple sugars before and during long workouts, you can tap into your body’s fat stores and use them to fuel your workout. Pairing this nutrition strategy with long, slow runs or carbohydrate depleted runs for advanced runners promotes efficient fat burning. Avoiding blood sugar & insulin spikes post run also promotes better fat burning. Recover with UCAN with protein to replenish your glycogen, repair your muscles, and continue burning fat.


4. Find and Improve Your Bonk Point

To find your bonk point, see how long it takes to run until exhaustion in training.  Bonking isn’t just about fatigue. It’s the point where you cannot maintain your pace and have slowed significantly. To improve your bonk point, start challenging it every seven to 14 days. Advanced runners, who have proven that they can complete a distance and want to finish faster, can improve their bonk point with no-carb runs lasting 80 to 90 percent of their bonk point.


5. Happy Stomach

A lot of runners find that their stomach can’t handle the traditional fueling recommendations of taking in fast-acting carbohydrates like sugar-based gels, chews, and drinks every 15-20 minutes. When you experience GI distress during a sustained effort, it’s difficult to consume the fuel you need. This puts you at a much higher risk of bonking. Fueling with a slow-burning energy source like UCAN allows your body to refuel less frequently while still maintaining steady energy, so you’re consuming fewer calories and minimizing your chances of GI distress.


About Greg McMillan

Greg McMillan is a runner, exercise scientist, and coach with the unique ability to combine the science of endurance performance with the art of real-world coaching. He has worked with Olympians, Boston Marathon qualifiers and new runners training for their first race. The bulk of his athletes are everyday runners balancing work, family and other commitments with their running. He coaches runners through his website