One of the most basic newbie questions asked is how many calories do I need to take on the bike? The typical answer is everyone is different and you need to train what your gonna race. While this is correct, the rub is that does not help find a place to start. Being that I love data, that where I recommend starting.

The first piece of information you need is your muscle mass. The best way to get this is using a pod. Since they are usually not very accessible, using a body fat scale is a more accessible alternative. You can find them cheap on Amazon. For illustration purposes (and to keep the math easy), say you weigh 200 lbs with 25% fat, here are the steps involved.

Step 1
Weigh yourself with a body fat scale. The scale will automatically calculate your percentage of body fat.

Step 2
Subtract your body fat percentage from 100 to get your lean mass percentage. For example: 100 – 25 percent body fat = 75 percent lean mass.

Step 3
Divide your lean mass percent by 100 to calculate the decimal for your lean mass percent. Here is an example: 100 / 75 – .75

Step 4
Multiply your lean mass decimal by your total body weight to calculate your lean mass weight. If you weigh 200 lbs., multiply 200 by .75 for 150 lbs. of lean mass.

Knowing that your lean muscle mass is 150 lbs in this example, your body can take about 2x that lean muscle mass number to then get calories / hr. Therefore, a good start is taking 300 calories / hr. This is for aerobic ride (70.3 and/or 140.6 distances). People racing sprints very rarely need this level of nutrition so let’s keep it to long course racing. Some people can push this higher, some have to go lower. Plus finding the right mix of carbs to protein, liquid vs solid, etc. ratios are very individual specific. But, this gives you a starting point to start training from. This is where you need to listen to your body and recognize any GI related stress.

This certainly gets you a starting baseline of your calorie intake. Happy training.