What's the Perfect Triathlon Racing Weight?

Throughout my years in triathlon I’ve heard a lot of athletes ask about a particular physiological subject of which I’ve never placed much stock in myself. A simple topic that we as a nation are obsessed with: body weight.


Macca’s Story

The general consensus among endurance athletes, many of which are triathletes, is that “the lighter I am, the faster I will go.” Chris McCormack (affectionately known at Macca) directly challenged this line of thinking in an article for Triathlete from June 2015. Chris began by noting, “I’d say 99 percent of people I talk to in this sport believe weight’s relationship to performance is as simple as ‘less is better.’ This is a half-truth – the weight puzzle is much more complex. There has never been a bigger topic of discussion within my team of advisers.”

Macca goes on to describe his personal experience in being young and racing short distance triathlons to growing older and moving up to the long course events. As a young guy busting out Olympic distance races, lighter indeed was better. As he says, the natural speed, flexibility, and youth fed the lighter body. For a race that’s short, dynamic, and fast, a leaner body worked. That philosophy, however, did not apply to Kona.

McCormack continued racing with his ideal race weight into the long course triathlon world. It worked for a while, but eventually the price of being too lean reared its ugly head. His IRONMAN World Championship goals were not achieved. The great Mark Allen personally informed him of his error. “Macca, you need to be fat in July to win in Kona. You’re race-ready all year! That approach does not win Hawaii or support athletic longevity.”

He found that taking the approach of how a professional boxer would train was the key to success. Gain weight, train heavy, and build strength in the offseason, then add more volume and speed as the weight begins to drop. In the end, his optimal triathlon race weight was not what it used to be. He had more success in the long course distance at a heavier weight than he ever did at his former ITU racing weight.

Take some of Macca’s final words as a reminder that the half-truth is not to be bought: “Skinny does not always mean faster. We all have an optimal race weight, and we all have to find that. You can feel it, and you know when you are there. Be attentive to your training and record things when you’re feeling good. Do not get caught up in the mind-set that lighter is always better.”


Perfect Triathlon Race Weight Happens When You Race Well

TriDot coach John Mayfield offers his thoughts on the subject as well, “Ideal racing weight is the lightest you can race while maintaining top health and performance. This may take some trial and error and personal experience to find. Prioritize a clean, whole food diet; appropriate intensity and duration in training; and get adequate recovery. The body is actually very efficient at regulating appropriate weight as well as hormone levels, energy, and metabolism when these are taken care of.”

Similar to Macca’s thoughts, finding the optimal triathlon race weight for you may take some doing. It also depends on the distance. But in the end, you will feel it. You’ll know the right weight when you get there.

In another article for Triathlete, Matt Fitzgerald, certified sports nutritionist, states that “While some athletes are naturally skinnier than others, each athlete has an ideal racing weight that is attained when he or she has gotten rid of as much excess body fat as possible through healthy nutrition and proper training.” The question is, how do you know what is excess body fat and what is healthy body fat?

Much like Macca and Mayfield, Fitzgerald claims that ideal body weight and optimal body fat percentages are attained by your functional performance. In other words, when you’re really, really fit and you’re racing well. When everything works and your triathlon race day is a beautiful success, record your body composition data. Most likely, that will be your ideal weight and body fat percentage.


Finding the Right Weight by Body Fat Percentage

However, if you haven’t achieved that breakout performance yet, there are guidelines to follow.  According to Fitzgerald, “Given the fact that body fat is the primary determinant of ideal racing weight, the best way to estimate it is to calculate how much you will weigh after you’ve reduced your body fat percentage to the optimal level for you.” Of course, he concedes that the optimal percentage is not the same for everyone. Factors such as gender and age come into play. Therefore, there are ranges for optimal body fat percentage based on these two factors. For example, the optimal range for men of 20-29 is 3-10% while the same age range for women is 10-16%.

Using the ranges provided by Fitzgerald, you can analyze what your current body fat percentage is, figure the goal percentage you want to be at, and then calculate how much you will most likely weigh once that goal body fat percentage has been achieved.  Fitzgerald gives the calculation steps in his article.  He uses the example of a 38-year-old female triathlete attempting to shed body fat in order to fall into the optimal range.  How much will she weigh when she reaches that goal?

In the hypothetical example, the woman weighs 140 pounds and has 22% body fat.  Her goal is to be at 17%, which is the upper limit of her ideal range.  Here are Fitzgerald’s calculation steps:

Step 1: Calculate your body fat mass. Body fat mass = current weight multiplied by current body fat percentage. In this example: 140 lbs x 0.22 = 30.8 lbs.

Step 2: Calculate your lean body mass. Lean body mass = current weight minus fat mass. In this example: 140 lbs – 30.8 lbs = 109.2 lbs.

Step 3: Calculate your goal weight. Goal weight = current lean body mass divided by goal lean body mass percentage. (Note: Your goal lean body mass percentage is 1.0 minus your goal body fat percentage expressed in decimal form.) In this example: 109.2 lbs ÷ 0.83 = 131.5 lbs.

As can be seen, if the woman achieves her optimal racing body fat percentage through smart training and diet, she should arrive at approximately 132 pounds.  That’s 8 pounds less than her current weight.

Remember that in the end this may not actually be the woman’s ideal triathlon race weight. Again, race distance and general performance should factor into the end result. But for the beginner, calculating an ideal weight based off of the above data can be a good starting point.


Few of us are on the level of Macca and many may be within or outside the optimal triathlon racing weight. However, we must remember that lighter does not always mean better, ideal race weight typically happens when you’re performing at your best, and body fat percentage is a great way to gauge optimal triathlon race weight.


Do you know what your perfect triathlon racing weight is? What experience have you had by experimenting with your weight?


McCormack, Chris. “Chris McCormack On The Triathlete Weight Debate.” Triathlete. Competitor Group, Inc., 17 June 2015. Web. Accessed 30 Dec 2016.

Fitzgerald, Matt. “The Do’s And Don’ts Of Getting Leaner.” Triathlete. Competitor Group, Inc., 17 June 2015. Web. Accessed 30 Dec 2016.

JARED MILAM is a professional triathlete, TriDot coach, and member of the Tri4Him Pro Team. He has 16 years of competitive running experience and 11 years of competitive triathlon experience with a half Iron PR of 3:59 and a full Iron PR of 8:30. Coaching under the TriDot system since 2011, Jared loves working with aspiring triathletes of all ages and performance levels.

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