The University of Zurich set out in 2009 to prove the obvious: that leaner and lighter triathletes perform better in races. They recruited 184 participants in that year’s Ironman Switzerland to help with their investigation. Before the race, the team measured the body weight and body fat percentage of each subject. Afterwards, they compared these measurements against the athletes’ swim, bike, run, and finish times. And what did they find? The obvious. That being lean has a significant positive effect on triathlon performance.
The Zurich study may prove that leaner triathletes are faster than ones with more body fat, but is losing excess body fat likely to improve performance? In a study by Southern Connecticut State University, eight cyclists reduced their food intake by 250 to 500 calories per day for 10 weeks and lost an average of 5kg. This change resulted in a 9% increase in their power-to-weight ratio, an excellent measure of cycling performance. Eleven other cyclists serving as controls lost no weight and saw no improvement in performance.
So, what’s the optimal body fat percentage for triathlon performance? It differs by gender, age, genetics, and personal history. Elite male and female triathletes are typically in the range of 7-13% body fat, respectively, but these levels aren’t attainable by most. The only way to determine your personal ideal body fat percentage for triathlon performance is to actually attain it through proper training and diet. So it’s best to focus on the process instead of the outcome.
1 Shed KG not power
Losing weight doesn’t necessarily lead to better performance. So how do you shed the pounds but still increase the power?
Dieting is about losing weight for the sake of losing weight. Performance weight management is about getting leaner for the sake of performing better. This is an important distinction, because not all ways of losing weight result in better performance. In particular, the common dieting practice of severely restricting calorie intake tends to sabotage endurance performance by robbing the body of the energy it needs to fuel workouts and recover from them. Triathletes who diet in this way typically get slower even as they lose weight.
The Connecticut study from the opening page proves that calorie restriction undercuts intensive training. In addition to the eight cyclists who reduced their calorie intake and the eleven controls who didn’t, the study also included eight cyclists who added high-intensity intervals to their training in order to get fitter and seven more who added intervals and cut their calorie intake.
Predictably, those who added intervals improved their power output and increased their power-to-weight ratio even though they lost no weight. But those who combined intervals with dieting failed to improve their power-to-weight ratio even though they did lose weight. The calorie reduction had robbed them of the ability to adapt to and benefit from intensified training.
Listen to your body
Your body knows how much food it needs not to exceed your daily energy requirements. If you listen to it, you’ll consistently eat the perfect amount to train strong and shed excess body fat. One of the most common misconceptions about weight loss is the idea that the appetite can’t be trusted.
Most people believe that if they eat as much as their tummy wants, they’re bound to overeat. Likewise, many triathletes believe that, in order to lose weight or maintain their ideal racing weight, they have to ignore their appetite and put up with a little hunger each day. None of this is true.
You can trust your appetite to guide you to the right amount of food intake. The problem is that most people today unconsciously eat more than they need to satisfy their hunger. But it is possible to reduce food intake without creating hunger by consciously avoiding the common traps that cause us to mindlessly overeat.
2 The Right Choices
Much of performance weight management is down to your psychology. Food choice, size and tracking will help you to establish a leaner, faster you…
In seeking to shed excess body fat, triathletes need to focus less on the quantity of food they eat and more on the quality of their food choices. High-quality foods are natural, unprocessed food types that humans have been eating for centuries.
In my classification system, there are six such food types: vegetables; fruit; nuts, seeds and healthy oils; whole grains; dairy; and unprocessed meat and seafood. There are also four low-quality food types, which are simply processed versions of these same foods. They’re refined grains, sweets, processed meat and fried foods.
The high-quality food types are more nutrient dense (i.e. higher in total nutrition) and less energy dense (lower in calories) than the low-quality food types. So when you increase your overall diet quality by eating fewer low-quality foods and more high-quality foods, you’re able to satisfy your total nutrition needs and your appetite with fewer calories, and as a result you shed excess body fat without sacrificing performance.
The most common trap is the plate-cleaning instinct. People are hardwired to finish off however much food is placed in front of them. This is a big problem today because portion sizes have increased drastically over the past 40 years. To escape the plate-cleaning trap, develop a habit of mindfully eating until you’re comfortably full and then stopping, even if there’s leftover food on your plate that must be saved until later.
Once you’ve developed a better sense of how much food you really need to satisfy your appetite, you can then adjust the amount of food you prepare and serve yourself at home and the amount you order when eating out so that the temptation to overeat is further reduced.
Tracking body weight
It’s important to keep in mind that your goal isn’t to lose weight but to lose excess body fat. The only way to know for certain that you’re in fact losing body fat is to measure your body composition. This can be done in a variety of ways. The most accurate method is the DEXA scan, a medical device that’s most often used to measure bone mineral density. But it’s difficult to access.
The most convenient way to measure body composition is with a body fat scale using bioelectrical impedance to estimate body fat percentage. While not as accurate as some other methods, these products are accurate enough that if you see a trend in one direction or the other – either increasing or decreasing body fat percentage – you can trust that the trend is real, even if the exact number you’re seeing is a little off the mark.
All triathletes should step on to a body fat scale once a week or so. This will provide valuable evidence
that your performance weight management efforts are working and will also allow you to make quick adjustments when they’re not.
3 Fuelling your training
As a triathlete, you’re not seeking to get leaner for its own sake. So how do you fuel your workouts and what training is best for becoming lean?
The best foods for becoming and staying lean are the six high-quality food types, which are vegetables; fruit; nuts, seeds and healthy oils; whole grains; dairy; and unprocessed meat and seafood. Epidemiological studies have shown that people who eat each of these food types frequently are leaner than people who eat them less often. A 2007 University of Minnesota study found that, within a population of nearly 6,000 men and women, those who ate the most whole grains had the lowest body mass index (BMI).
Some specific foods, including yoghurt, are particularly beneficial for performance weight management. You wouldn’t want to eat an all-yoghurt diet, though. Promoting a lean body composition isn’t the only thing your diet must do for you. It must also support all-round health. This requires that you eat a balance of all six high-quality food types and a variety of foods within each type.
Remember that, as a triathlete, you’re not seeking to get leaner for its own sake. You’re seeking to get leaner for the sake of performing better. So it’s important that you regularly monitor your performance. There are a variety of ways to do this. One way is to conduct formal test workouts. My favourites are ‘relaxed time trials’, or 95% efforts over Olympic distance.
These workouts are hard enough to accurately assess fitness but not so hard that they’ll disrupt the overall flow of your training.
Aim to conduct a performance test in each tri discipline once every four to six weeks, and stagger them so that you never do more than one such test in a single week.
Training for racing weight
Research has shown that the most effective training approach for fat loss is one that is based on high-intensity intervals. But studies have also demonstrated that the most effective approach for increasing endurance fitness and performance is one in which 80% of training time is spent at low intensity and only 20% at moderate to high intensity.
A 2014 University of Salzburg study found that athletes who did 57% of their training at high intensity for nine weeks lost 3.7% of their body mass, while athletes who did just over 20% of their training at high intensity lost no weight. But these ‘80/20’ athletes experienced a whopping 11.7% increase in VO2max, compared to a modest 4.8% increase in those who emphasised high intensity.
What does this mean for you? It means that if weight loss is your highest priority, you should base your training on high-intensity intervals and you should do this only at times when you’re not aiming towards peak performance in races. And when fitness and performance are your highest priorities, you should train by the ‘80/20 Rule’ and rely on your diet to shed excess body fat.
How to prioritise your nutrition to your triathlon training
4 Race and rewards
When you should adopt your racing weight is key to tri success. But don’t forget to reward yourself come the off-season…
To reach your optimal racing weight, adopt an eating schedule on which you predictably start to feel hungry shortly before it’s time for your next meal or snack throughout the day. Once you’ve settled into this routine, stick with it. Research indicates that people who eat on a consistent schedule every day are leaner than people whose eating schedule is erratic.
Your workouts should be timed to occur when your last meal or snack has been fully digested but your blood sugar level is still high (usually that means two to four hours after a full meal).
The performance weight management process should be divided into two phases. The first is a weight-loss focus phase: a four to eight week period during which you pursue weight loss as your primary goal through means such as calorie restriction, reduced carbohydrate intake, and high-intensity, low-volume training that would ruin your aspirations of getting race-ready if
used within a race-focused training cycle.
Triathletes aren’t robots
A weight-loss focus phase should come right before the start of formal training for a race or series of races. At that point, you need to transition to eating and training for performance through a focus on diet quality and ‘80/20’ training. You won’t lose excess body fat as quickly during this second phase but you’ll continue to get leaner as you gain fitness for an upcoming race or races.
After your last event of the season, it’s okay and even beneficial to take time off from training and enjoy some dietary indulgences. As long as you limit this period of reward to a few weeks, you won’t lose so much fitness or gain so much weight that you can’t easily reverse these changes when you return to your normal exercise and eating habits. And you’ll probably find it easier maintaining these habits the rest of the year when you do allow yourself to be lazy, eat dessert, and gain a kilo or two during the off season. Triathletes aren’t robots!
Matt Fitzgerald is the author of Racing Weight and the Racing Weight Cookbook from Velo Press.