You might be better off working on your power output than trying to diet to a magical number…

Does race weight matter?

There is so much controversy over weight and performance it’s enough to make your head spin. The common theory of “less equals fast” gets bandied around a lot, and many athletes and age groupers feel under pressure to reduce weight in the name of performance gains. But will it really make a difference? 

Really we should look at body composition, because muscle weighs more than fat. Top endurance athletes tend to waiver on the lower edge of the weight and body fat percentage scale but this often comes at a price, such as illness, injury or burnout. For shorter distance racing being whippet-like can have an advantage, most prominently on the run phase.

However, if you look at short course cyclists and swimmers, they are powerhouses designed to hit unbelievable speed over shorter distances through strength and brawn. Longer distance athletes tends to have a stronger build to facilitate effort over a longer duration of time because with long distance comes injury risk, so you can’t run around like a stick insect.

The problem with triathlon is that it is three sports over many different distances. Therefore any claim that being thinner or lighter will make you go faster is too categorical – it’s a very individual thing. How many times have you been busting a gut cycling up a hill to see someone more portly overtake you at cruising pace? You only need to stand at the sidelines of a triathlon and watch all the different shapes and sizes to see there isn’t a direct correlation between thinner and faster.

While reducing your weight may help your run, it could be to the detriment of your swim and bike. For swimming you need muscle to be strong and fast, plus a little fat to help with buoyancy. For cycling, it’s all about power and endurance which can have very little to do with weight. Increasing your power output on the bike by just 20 watts will give you more speed than if you lost half a stone in weight.

For elite athletes, it’s a different story. We talk about “marginal gains”, and weight is the very last thing to look at after they have done everything else. But for age groupers, losing weight will make less difference. Balance is key. You wouldn’t want to miss out on cake after a Sunday ride after all, it will have been well earned.


Good, solid training will give you far greater performance gains than weight loss. Your body composition will naturally alter through a consistent training routine. Remember staying healthy is the primary objective!


1. Ensure you are fuelling with good quality macronutrients (carbs, proteins, fats) plus vitamins and minerals to help your body recover sufficiently. A calorie deficit will affect your performance far more than a few pounds of extra weight will.

2. If you decide to work on reducing body fat percentage and refining your body composition, it is best executed off season when it won’t affect race performance. It needs to be done sustainably and slowly. Any drastic changes will wreak havoc on your body.

3. Muscle is really important for strength and power in triathlon. Incorporating good strength, conditioning and core programmes into your training will help build power and reduce injury risk, which will lend itself to a more consistent performance.

WORDS: Amy Kilpin IMAGE: Adam Hollier

Read more like ‘does your race weight matter?’ in our jam-packed training section for tips on all aspects of triathlon…