Tapering nutrition: what should you eat during the taper period

What you eat during the taper can make or break your race. Here’s how to master pre-race nutrition


Simply put, tapering is the art or science of peaking for an event by reducing training load for a certain amount of days.


Louis Passfield, professor of sports science, puts it another way. “In your day-to-day training, you’re trading fatigue with the potential benefits of improving fitness. When it comes to your taper, you want to clear the fatigue and accumulate freshness to maximise that fitness. Get it right and you could enjoy performance improvements over your pre-taper of 2-3%.” For an Olympic-distance athlete with a PB of 2:30hrs, that’s up to a 4:30min saving; for a 12hr Ironman athlete, over 22mins.

According to research by exercise physiologist Inigo Mujika, optimal tapering duration ranges between eight and 14 days with training volume dropping by around 41-60% by reducing either the session duration or frequency. But maintaining intensity is key to ensure you don’t lose speed.

Tapering: why it’s important and what you should do the week before your triathlon


This background impacts your fuelling strategy and namely whether you should ‘carboload’ or not. Carboloading’s a theory from the late 1960s that proposed depleting glycogen stores in the build-up to a race and then refilling them with a short period of high carbohydrates resulted in ‘supercompensation’, meaning cells could store higher levels of glycogen than previous. 

Subsequent studies have shown high glycogen concentrations can be achieved without this depletion phase and with as little as a 24hr period of high carbs, though most experts suggest 36-48hrs. According to world-renowned nutritionist Louise Burke, this sees carb intake rise from a general performance diet of 7-12g per kilogramme of body weight to 10-12g/kg and should comprise carb-rich sources like pasta, rice and potatoes, but keep the former two white to be gentler on the gut.

However, all’s not equal. “Carboloading’s relevant for events over 90mins only,” says noted exercise physiologist John Hawley (and husband of Burke). “You do put on weight when you carboload because, when you store carbohydrate in the form of glycogen, you also store water. But does the extra energy outweigh carrying up to 1-1.5kg in weight, common for a 70kg triathlete carboloading? I’d say it does, yes.”

That water retention is key if your goal race features a hilly bike route with peaks early on, because that excess won’t have time to sweat out. It’s your call whether this impacts on your strategy. Just bear in mind that this water-weight balancing act is heightened if you supplement with sodium bicarbonate. “The main reason my athletes use it is,” says nutritionist Nigel Mitchell, “is because it hyper-hydrates the body. The benefits are that, when working hard, it helps with bloodflow and circulation, as well as reducing the risks of hydration issues. The downside is that added weight.” 


Evidence also suggests that creatine and caffeine intake enhances glycogen storage.