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Training FAQ: How to reach ‘ideal racing weight’

Chris Case speaks with coaches, researchers, and sport scientists to answer all your training and nutrition questions.

Do you have a question on training, nutrition, or sport science that you’d like answered? Please email us to be included in Training FAQ.

Dear Chris,
I want to hit my “ideal racing weight” this season. How can I do that through diet?
— Jon

Dear Jon,
Competitive cyclists will look for every advantage to optimize performance. Often, that means seeking an “ideal racing weight” by altering their diet to drop pounds. The physiologists and nutritionists at the University of Colorado Sports Medicine and Performance Center often see athletes who are looking to better understand their ideal weight and how to get there. Many times they see athletes who have gotten the balance wrong, and with their weight loss comes declines in performance. Cyclists want to be as lean as possible so they can climb hills faster; but how lean is too lean? While there can be some advantages to reaching an ideal racing weight, there are many pitfalls associated with the endless pursuit of that weight.

I spoke with Jared Berg, one of the center’s physiologists, about how he and the university team go about helping athletes find their ideal racing weight.

In order to properly determine an athlete’s ideal racing weight, physiologists need to determine body composition. This is more important than targeting a specific weight because there can be complications with being too lean or too fat.

Twenty years ago, researchers had subjects undergo hydrostatic weighing, a method that measured the amount of water the subject displaced when he or she stepped into a pool. Today, the method is different.

“[Hydrostatic weighing] wasn’t very practical, and its accuracy depends on how good subjects were at expiring all the air out of their lungs while underwater,” Berg said.

Most physiologists and exercise specialists now consider skinfold calipers to be the tool of choice for determining body composition. There is also DEXA Scan technology, which uses a light X-ray scan to calculate lean body mass, bone density, and fat mass. According to Berg, while DEXA is the most accurate method to assess body composition, it can be expensive and, therefore, not as feasible for repeat assessments.

“If you consistently use skin calipers, you can sufficiently assess a body composition trend which will ultimately prove more useful than knowing your precise body composition from DEXA once,” Berg said.

At the Performance Center, Berg and his colleagues use Musclesound, a skinfold-method substitute that uses an ultrasound wand to more accurately measure fat at corresponding skinfold sites. Once an athlete’s body composition of both fat and lean body mass is determined, what do you do with those numbers? Normative charts can help physiologists and physicians understand how much body fat is ideal for various populations. The following data, for example, from the American College of Sports Medicine define what is healthy/fit with regards to body fat, as it relates to one’s risk for cardiovascular disease. (Excellent, or very fit, is at the lower end of the range; good, or generally fit, is toward the higher end of the range.)

  • 15-21% for women age 20-29
  • 16-22% for women age 30-39
  • 19-25% for women age 40-49
  • 21-29% for woman age 50-59 and older
  • 8-14% for men age 20-29
  • 11-17% for men age 30-39
  • 13-19% for men age 40-49
  • 15-21% for men age 50-59 and older

Athletes do not necessarily need to be in the above body composition ranges to be healthy, according to Berg. Average body compositions range up to five percent higher than the high end of these ranges. However, athletes or individuals that are five percentage points higher will have an increased risk of cardiovascular disease and other metabolic dysfunctions like diabetes. And, more to the point of this discussion, they’ll have a decreased aptitude for climbing hills on their bike.

The physiologists at the Performance Center work with some of the best cyclists in the world. They have learned that professional male riders typically have body fat measurements between 8 and 11 percent, and females have between 14 and 18 percent, using either their skinfold or Musclsound methods.

“Within these ranges, we often see climbers on the leaner end of these ranges, with time trial specialists being on the higher end of the ranges,” Berg said. “The reality is one athlete’s optimal body composition may be different than another athlete’s optimal body composition, even when competing in the same discipline.”

There are many problems with being too lean. Berg and his colleagues have noticed the following issues when male athletes get below 8 percent, or when females fall below 14 percent:

  • Tiredness, low energy, and/or poor mood
  • Prone to illness
  • Poor training quality
  • Difficulty maintaining muscle mass
  • Suppressed high-intensity efforts
  • Low levels of testosterone, insulin, and thyroid hormones
  • Food obsessions
  • Obsession with training
  • Poor sleep quality, which makes recovery less effective
  • Social life disruption because of one or several of the above

After you have yourself on the fit end of your ideal body composition or race weight range, you can start putting your new ideal body composition/weight to the test.