This post provides an easy guide to determine how many calories you need to fuel your ride, and it includes a case study of a reasonably hard winter endurance ride.

It’s not hard to work out your fueling requirements, but the cost of getting it wrong is a slow wilting of energy and power.  So, take a minute and turn this into a useful tool for your cycling.

Here are the key facts in summary.

• You burn around 700 – 900 calories / hour when riding reasonably hard (Zones 3 & 4 in British Cycling’s scale, or 6 & 7 out of 10 in Sufferfest’s scale)
• Your body stores approximately 1,000 – 1,350 calories of easy to access fuel (glycogen)
• A gram of carbohydrate or protein contains 4 calories of energy, and a gram of fat contains 9 calories.  But, please note that it takes the body longer to convert protein and fat into energy than it does to burn carbohydrates
• You can determine how many calories your ride will require, subtract the calories your body stores, and the amount left over is the number of calories you need to consume before and during your ride.

60 mile endurance ride case study.
As a rule of thumb, your muscles store enough carbohydrate for around 90 minutes of reasonable effort, and you’ll have extra fuel coming into your system from your pre-ride meal. When you are riding reasonably hard in the wintertime, you’ll burn somewhere around 700 – 900 calories per hour. So, a three and a half hour ride requires 2,440 – 3,150 calories.

If you’ve consumed 500 – 600 calories at breakfast, that adds approximately 40 minutes to the 90 minutes of fuel in your muscles and liver. That leaves another 80 minutes of riding to be fueled by what you eat on the bike. So, you need to consume 930 – 1,200 calories while you’re riding.

There are 4 calories in a gram of carbohydrate or protein, so you need to consume 230 – 300 grams of carbohydrate/protein while you are riding. One banana has about 25 grams of carbohydrate, and an energy gel has 30 – 40 grams. Therefore, you have a shortage of 175 – 245 grams of carbohydrate (700 – 980 calories) on this long winter ride if that’s all you eat, and you will bonk!!

You can consume the extra 175 – 245 grams carbohydrates however you wish, but my recommendation is to start with energy powder in your water. In that way you are taking on a steady supply of carbs (as long as you drink regularly). Even in winter you should get through at least two bottles of water, and that will be approximately 60 – 80 grams of carbohydrate (depending on what energy product you use). You can top that up with an energy bar or gel each hour, which will contribute another 105 – 140 grams of carbohydrate. I often use home made flapjacks (made with peanut butter and honey rather than butter and sugar) and/or wholewheat tortilla bread with peanut butter and set honey, as these contain more calories than gels and taste savoury, rather than sweet.