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Could fat-adapted training make you a better cyclist?

Michael Donlevy
2 Dec 2020

It starts with fasted rides but goes much further than that, but not all experts are convinced of its benefits

Christmas is beyond us and everything is pointing towards those summer months but where are you in your training programme? There’s a fair chance that, even if you didn’t balloon over the festive period, you’re trying to lose a few pounds while laying the groundwork for the rest of the year ahead.

There’s one way of doing it that’s become a big buzzword (buzzphrase?) in recent times: ‘fasted training’. But there’s also an extension of that which edges towards the extremes of what many coaches believe is feasible.

It’s guaranteed to help you lose weight and maintain a healthy weight, but it also requires you to ditch the carbohydrate that most of us use for fuel. It’s called ‘fat-adapted training’.

It starts with fasted training, so that’s where we’ll begin. Quite simply, this is when you ride on an empty stomach.

‘The easiest way of doing it is to eat your usual evening meal and train before breakfast,’ says coach Ric Stern of RST Sport.

‘Complete a steady ride of between 45 minutes and two hours, then eat breakfast when you get home. You can even do your normal training later in the day when you’ve refuelled. 'Being able to utilise carbohydrates is important for high-intensity efforts.’

Or is it? That’s where fat-adapted training comes in.

The case against carbs

Will Newton is a coach who has held various roles at British Cycling, and he has strong views on the drawbacks of over-consuming carbs.

‘As a species we’re the most sedentary we’ve ever been,’ he says. ‘Humans survived eons without a ready source of carbs, and now we have them we’re lazy.

'We suffer from a sugar/carb addiction that makes us want to eat all the time. You don’t need to eat, but how often do you find yourself staring in the fridge?

'We don’t have a constant need for food. Your body will figure out how to use fat for fuel.

‘This is advantageous in evolutionary terms,’ he adds. ‘If we hadn’t used fat for fuel we wouldn’t have survived. If you’re starving, it’s mid-winter and you need to chase an animal, I can guarantee you’ll approach your maximum ability as an athlete.

'So the argument for carbs is specious. Carbs weren’t around when we were chasing woolly mammoths.’

He is therefore an advocate of fat-adapted training. ‘It means burning stored fat during the day and relying on fat, more than carbohydrate, to fuel exercise.

'It’s achieved by eating a lower-carb, higher-fat diet and training in a fasted state. And it’s pretty damned horrible until you get used to it.’

That’s not selling it to us, it has to be said. So why do it?

‘Firstly, there are health reasons,’ says Newton. ‘There’s evidence that Type 2 diabetes can be controlled, even reversed, without medication, on a low-carb high-fat [LCHF] diet. You can also lose significant amounts of weight, and GPs are starting to recommend it for this.

‘As an athlete, it removes the need for constant fuelling, and means you suffer less gastric distress. And you’ll have better weight control, because it’s much harder to gain body fat eating this way.

'The idea that fat makes you fat is nonsense. It’s the overconsumption of carbs and sedentary lifestyles that make people fat.

‘LCHF appears to be anti-inflammatory, and athletes eating LCHF have reported faster recovery. From personal experience I don’t lose fitness as quickly after time off.’

How to do it

Calories matter less than with other eating plans, and you certainly don’t have to count them. ‘Calories take care of themselves because it’s very hard to eat that many,’ says Newton. But there are some guidelines.

‘Carb intake has to be less than 50g per day,’ he says. ‘Eat moderate protein – around 1g-1.2g per kilo of lean body mass. Then you need to eat high-fat foods: eggs, avocado, olive oil but not processed oils like sunflower, nuts like almonds and macadamias, moderate amounts of dairy and meat. You can also have green leafy veg and colourful veg, but not starchy root veg.’

Not everyone is sold. ‘The evidence on being fat adapted is equivocal,’ says Stern. ‘There’s some evidence that it can help with weight maintenance or loss, but little to suggest that it actually helps with performance – increased power output.

'Fat-adapted and fasted rides are different things, and I’ve never suggested anyone should become a fat-adapted athlete.’

‘Even if you teach your body to become better at fat utilisation, most people are still likely to ride at levels where glycogen from carbs is the primary source of fuel, especially in a race,’ says coach Paul Butler.

‘If you’re well practised at fuelling yourself – if you always fuel your training rides – you’re more likely to achieve your potential on those key days in the saddle.’

Newton disagrees: ‘One groundbreaking piece of research was called the FASTER study, which tested elite endurance runners on both high-fat and high-carb diets.

'One blogged that at 89% of his maximum heart rate he was burning mainly fat. I’ve experienced something similar, riding at or above my threshold for over an hour. There is evidence that it is possible to perform at a high level.’

Tour de France cyclists eat huge breakfasts, huge evening meals and eat and drink regularly throughout every stage,’ counters Butler.

‘They train for months and eat and sleep well and they start the Tour with low body fat and end it with even lower body fat, and the last I heard they can ride a bike very fast for very long periods. Don’t overcomplicate this.’

‘The pros do consume carbs, but they’re outliers,’ says Newton. ‘Most 45-year-old men are slightly over-fat, have some insulin resistance and aren’t great at metabolising carbs while exercising.

'Most amateurs would perform better fat-adapted, if for no other reason than they’d be 5% lighter.

‘It’s rumoured Chris Froome is fat-adapted – he’s Tweeted photos of his breakfast and there’s no toast or oats in sight. Romain Bardet has taken this approach and he’s taken the step below Chris on the Tour de France podium.

'Pros are very secretive, but with the level of training they do they’ll be fat-adapted to a degree, because you can’t consume enough carbs to fuel that sort of training volume.’

‘Some research has shown that people on a LCHF diet perform better when fed high carbohydrate during intense exercise,’ says Stern.

‘However, I’m not certain what would happen if you did this regularly. I doubt you’d stay fat adapted. Other than for weight loss I’m not sure I’d recommend it – and there’s plenty of research that shows a moderate to high-carbohydrate intake and low-fat diet can also be excellent for weight loss.’

‘In the early stages it’s hard, and it takes a while for the effects to kick in – three to four weeks to make the initial step to not feeing horrible, and to be able to train at your previous intensity,’ says Newton.

‘You’ll need to scale training back in that time, but I’d say it takes one to two years for your body to make all the enzyme changes it needs to for your body to be fully fat adapted.

‘I’ve been doing this three and a half years and my weight has stayed the same, between 77.5kg and 78kg. I’m leaner and I’ve put on muscle from just two 45-minute lifting sessions per week.

'I have a 365-day six pack, and I don’t try. I’m not genetically gifted, but I don’t struggle to maintain it.

‘Use carbs when you’re racing if it makes you feel better,’ Newton adds. ‘If it works for you, great. I’m not saying they’re evil.

'You don’t have to avoid carbs, but 10-15g per hour of hard exercise should be fine. You have a choice – you can try it and it may work or it may not. But give it a real chance.’

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