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by Alan McCubbin
September 12, 2018
Photography by Kristof Ramon
When it comes to getting the most out of your cycling, few things are more important than recovery. It’s not enough to just smash yourself on the bike, day after day — you also need to give your body a chance to recover, and recover properly.
In this three-part series, dietitian Alan McCubbin takes a deep dive into the nutrition science behind recovery, giving you practical advice that you can apply to your own riding. In the first instalment we introduced the three Rs of recovery – refuelling, repair (and adaptation), and rehydration. We discussed that all three of these are context-specific, and depend on the ride just completed, the ride coming up, and the time until that next ride.
Today we’re looking at the second R: repair (and adaptation). What is it? When is it important? And what should we eat and drink to optimise it?
When you exercise, you put your body under a level of stress. Which is a good thing — that’s how you adapt and get fitter, stronger and healthier. If you didn’t there’d be no physical benefit to training at all. But along with the exercise stress comes wear and tear to your muscles, particularly if they’re worked very hard or for a long time. This is often referred to as “microtears”, tiny little tears in the muscle fibres that in themselves don’t constitute an injury, but still need repair in order to optimise the muscle’s functioning next time.
It’s the protein from food that facilitates this repair process. I’ve written for CyclingTips previously about how protein helps with muscle growth and repair.
Another area that can sustain damage during exercise but often gets overlooked is the gut. As previously explained on CyclingTips, the cells lining the gut are quite susceptible to a lack of blood flow, and this can cause significant damage that affects the body’s ability to absorb nutrients and prevent bacteria and other nasties crossing into the bloodstream. This sort of damage typically only occurs during prolonged exercise (at least two hours) in hot conditions (typically at least 30ºC), where the core body temperature can reach 39ºC or more for a sustained period of time.
We also now know that having a frequent supply of carbohydrate during a ride (only 45g per hour has been studied to date, but less may be adequate) prevents this damage occurring, probably by redirecting at least some blood flow to the gut in order to digest and absorb the carbs. Again, protein is likely to be needed to repair this damage, although as far as I’m aware the optimal amount and timing for this process has not been studied.
As well as the repair of muscle fibres themselves, there’s a bunch of other adaptations that your body makes to the exercise stress of riding your bike. Within the muscle, these include an increase in the number and capacity of mitochondria (the little bits inside every cell of your body that produce energy), the number of capillaries (tiny blood vessels) that supply the muscle with oxygen and nutrients, and various proteins and enzymes within the muscle that help transport and use oxygen and nutrients, turning them into energy.
In addition, as blood volume expands with training, the body makes more haemoglobin to carry oxygen in the blood, as well as adaptations to the heart muscle itself that improve its ability to pump. Although not all of these areas have been studied in detail, it’s thought that most if not all of them rely on protein to maximise the body’s response to exercise.
So how much protein do we need after a ride to maximise this repair and adaptation? To date, the vast majority of protein research has centred around protein and weight training, so it’s hard to know for sure. There are a couple of studies, however, that suggest consuming protein after endurance exercise does improve the body’s adaptations to training over several weeks. But most of the short-term studies to figure out the optimal amount, type and timing of protein post-exercise, are still centred on people lifting weights.
From that data, we can say that the optimal amount of protein in a single meal or snack after exercise appears to be around 0.4 grams of protein for every kilogram of your body weight (e.g. 28g for a 70kg rider), repeated every 4-6 hours over the day. Consuming protein more frequently doesn’t seem to help.
Interestingly, whilst both the type of protein and timing were once thought to be important considerations, nowadays many of the key researchers in the field tend to feel this is not actually that important. One of the most prominent researchers in the field, Professor Stu Phillips from McMaster University in Canada, recently explained on a podcast “… What’s become more and more clear is that the timing maybe doesn’t matter as much as we once thought … the big discussion these days is around dose”.
So don’t feel like you need to have a protein snack lined up the second you step off the bike. If you like to take an hour or so to clean your bike, have a shower, and check your Strava account, it won’t really matter.
You don’t need to rush to get protein in straight after your ride.
Other researchers have focussed on whether the type of foods you eat matters. Traditionally, studies looked at basic powdered forms of protein like whey (a group of proteins found in milk) compared to soy or casein (the other types of milk proteins). But more recently, studies have looked at whole foods, finding, for example, that whole eggs were slightly superior to the same amount of protein from egg whites alone, possibly due to the other nutrients found in the yolk.
To date I’m not aware of any studies combining protein foods into a whole meal, with rice and vegetables for example. But the good news is, if your ride finishes just before a meal, at this stage it looks like you don’t need a protein shake if you’re about to get a decent serve of protein from meat, fish, chicken, eggs, tofu or dairy products. And of course, you’ll get a bunch of other nutrients in those foods that are helpful to your overall health.
As mentioned in the first piece in this series, we always need to consider context when thinking about recovery nutrition. Do we actually need to focus on protein after every ride? Probably not. It will depend on the level of exercise stress.
If you went for an easy bunch ride with your mates, or an easy spin on the trainer at home, chances are you haven’t really done much muscle damage, nor caused enough stress to need much in the way of protein. But if you’ve done a more taxing ride, then it’s worth thinking about your protein over the rest of the day and getting those 0.4g-per-kg serves every few hours.
0.4 grams per kg per meal can add up to a significant amount of protein if you’re doing it several times over the day — at least 1.6 and in some cases more than 2 grams per kg of body weight a day. Whilst many people consider this amount of protein extreme (and certainly more than previous guidelines for endurance athletes), it’s worth noting that a 2016 study that aimed to calculate the protein needs of endurance athletes concluded that 1.85g per kg per day was optimal.
In the pro cycling ranks, Team Sky nutritionist Professor James Morton often quotes a figure of 2-2.5g/kg/day for riders during a stage race. And in an incredibly detailed study of all nine Movistar riders during the 2015 Vuelta a España (where trained researchers literally weighed every rider’s meals before and afterwards, including bidons and food taken on the bike), the average protein intake across riders was 3.3 grams per kg per day, and 55g (or 0.8g/kg) in the period after each stage.
Finally, it’s worth considering the interactions between nutrition and the actual exercise stress itself. There’s a temptation to think that if exercise is a stress to the body, then trying to alleviate that stress is a good thing. But ultimately that stress is what stimulates the body to adapt and improve as a result of training.
Nutrition strategies like antioxidant supplements (including Vitamin C tablets) that were once thought of as a good idea to reduce the body’s stress response to exercise have since been shown to actually reduce the amount of adaptation to exercise.
Another area that’s been looked at is whether there may be an advantage to deliberately go into training sessions under-fuelled, to increase the stress on the body’s energy production systems. Study results have been mixed in this area in terms of ultimate benefits to performance, but as Team Sky’s James Morton often discusses, this strategy should only be used if the upcoming ride is an easy one – under-fuelling going into a hard training session or race is going to impair performance. It’s what he calls “fuelling for the work required”, a topic I wrote about on CyclingTips a few years back.
Next time we’ll conclude our series with a focus on the final of the three Rs: rehydration. We’ll investigate just how important it is to replenish fluid and electrolytes after a ride, and chat to a researcher that’s been examining this in a real-world context.
Alan McCubbin is an Accredited Sports Dietitian, Accredited Practicing Dietitian and past president of Sports Dietitians Australia. He is currently studying his PhD in sports nutrition at Monash University. He is also the founder of Next Level Nutrition, an online sports nutrition consultancy through which he works with a range of athletes from recreational to Olympians.
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