Avoid the dreaded bonk by knowing when to fuel

Olympic silver medalist Dotsie Bausch takes a break from a ride to fuel up. Show me the numbers: How much is enough?
Going into exercise, your body can store an average of 2,000 carbohydrate calories in the form of muscle and liver glycogen and glucose in your bloodstream. After about 60 to 90 minutes you burn through your carbohydrate stores and your body requires consistent fueling to avoid the dreaded “bonk.”
Avoiding the BONK

Top off your glycogen stores with 200 to 300 calories, 30 to 60 minutes before exercise. Eat a carbohydrate-rich snack that's easy on your stomach, such as toast with nut butter, a Bonk Breaker Energy bar, a banana and yogurt or oatmeal with milk.  During training find a pre-exercise snack that is easy to digest and provides a boost to get you going!
The trick is avoiding the “bonk” long before it happens. You may not feel hungry, but you still need to fuel. You can manage your carbohydrate load by fueling consistently and often.  You should fuel (that means CALORIES!) during training or races lasting 90 minutes or longer.  For rides lasting 90 minutes to 3 hours, aim to consume 30-60 grams of carbohydrate (120 to 240 calories) per hour. Your fueling needs increase as the duration of your rides exceed three hours and beyond. On longer rides aim to consume 45 to 90 grams of carbohydrate (180 to 360 calories) per hour.
As your calorie needs increase, you’ll want to consume a combination of liquid calories (ie. sports drink) and solid calories (ie. Bonk Breaker Energy bar).  Don’t get confused with calorie-free electrolyte drinks or caffeine, they do not provide true energy, FUEL means CALORIES! During training, build up your calorie intake until you find a range that works for you, and with a good mix of liquid and solid calories.
Go Easy on the System:

During exercise, your body will oxidize about one carbohydrate gram per minute, even when large amounts of carbohydrates are ingested. A combination of carbohydrates, such as glucose and fructose, increases carbohydrate oxidation rates by 20 to 50 percent when compared to glucose alone. Translation - more fuel to your muscles for energy and less fuel sitting in your gut causing gastrointestinal discomfort.  Fuel up with glucose and fructose rich carbohydrates, such as Bonk Breaker Energy bars, a Peanut Butter & Honey sandwich, and some gels/sports drinks (check the ingredients for a combination of glucose (maltodexrin) and fructose).
Timing: Find Your Rhythm:

Some athletes find fueling every 15 to 20 minutes is helpful, while others focus on consuming “x” amount of fuel by a specific time period or distance of training or a race.  Dedicate time during training to find the method that works best for you. 
Training doesn’t stop when your workout is done, so don’t forget to refuel immediately after exercise and maintain a healthy, balanced diet.  There is no cookie-cutter solution to your training and race-day nutrition needs, but these guidelines will support you in building your personal nutrition plan.
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