Carbs – how much is too much?

As with all things in fitness there have been many trends around carbohydrate intake over the past few years. After Atkins became popular and to a lesser extent paleo we started seeing carbs becoming demonized. All kinds of ridiculous myths were circulated with many people jumping on the low carb bandwagon to lose weight. Even bananas were outlawed by some gurus.

Then, with the rise in popularity of flexible dieting and the IIFYM crowd this got flipped on it’s head. Not only were carbs OK, anything would go, and your Instagram feed became a competition to see who could post the most chocolate With this blog, I attempt to explore the need for carbohydrates from a performance perspective. I’ll look at some of the evidence and then attempt to transfer that to practical application. Because, let’s face it, you’re more likely than not to be a-typical.

High carb or low?

Although there has been a lot written about low carb diets and fat adaptation for sporting performance there remains very little evidence to support this. I wrote a whole blog about this a couple of years ago, see here.

Louise M Burke has studied the evidence on this extensively and determined, based on the evidence available that there is no benefit to low carb performance and in 2016 she revisited the latest evidence and came to the same conclusion. But with a caveat:

“There should not be a choice of one fuel source or the other, or ‘black versus white’, but rather a desire to integrate and individualize the various dietary factors”

But more about this later. Let’s focus on the need for carbohydrates.

It depends on your sporting stimulus and there is no doubt that if your training is high intensity in nature then you will be burning your glycogen reserves a lot quicker than someone who trains in a slow steady aerobic state. If you are eating a diet that doesn’t give you adequate glycogen replenishment, it’s highly likely that fatigue will set in a lot quicker and your performance will suffer.

When you look at the evidence. It’s suggested that anything from 3-5 g/kg is optimal for active people and 5-8 g/kg for highly active people. Looking at the upper end of that a 70kg athlete will need 560g of carbohydrates a day. That’s quite a lot but it’s not a silly amount.

However, some evidence suggests that endurance athletes with a high training volume may need to go as high as 10-12 g/kg for high volume or twice daily training periods lasting longer than 3 days. that’s 700 – 840g of CHO for a 70kg athlete. Now THAT is a LOT! This might be why some of the IIFYM bros like to post pictures of disgusting post workout meals made up of a bucket of ice cream with melted Mars bars, honey waffles and caramel syrup on top.

(Now I have to say I’m sorry but if you are over the age of 8 that meal should be nowhere near your lips in my opinion. In fact, I would argue that if you are going to those lengths to hit your macros then you could probably make it easier to do it with whole foods and get a greater number of micronutrients, but you choose not to, in which case you need to look at your head…but that’s beside the point)

OK, so I don’t believe that low carb diets are great for most athletes and the likes of Dr Graham Close the head nutritionist for England Rugby and Dr James Morton from team Sky agree. Actually, I should rephrase that. Close and Morton believe that low carb diets are less than optimal and I agree with THEM. They’re far smarter than me.

But should you be shovelling all that sugar down your gullet?

How and why

Don’t forget that the research often studies elite athletes. In most cases, they are endurance athletes and quite often members of a developmental squad. So, will a 25 to 30-year old recreational sports person have the same metabolic requirements and adaptations as a 17-year old elite endurance athlete? Probably not.

Secondly, most endurance athletes will take on a large portion of their carbs in the form of liquids and gels during their event or match. This removes the need for the post workout pile of metabolic carnage mentioned above. It is still recommended that the majority of carbohydrates come from lower Gi or GL sources with the simpler sugars like glucose being saved for rapid glycogen replenishment.

As a highly active individual, you will have a much higher caloric requirement than a member of the Gen Pop (who is this Gen Pop and where does she live?). If you are following an evidence based approach then you should be consuming your macros based on grams per kilo gram, rather than percentages of overall calories. So, a 70kg athlete with a TDEE of 6,000kcal may likely have the same CHO requirement as a 70kg athlete with a TDEE of 4,000kcal.

The hard bit is working out what that optimal level is. Should it be 3 g/kg? Should it be5 g/kg, 8 g/kg or somewhere in between? Like, why not 4.5 g/kg?

This is where it is useful to keep a training and recovery log. If you have a very high volume training day and you find that your sleep that night is always compromised, then maybe you need to go a little higher on your carbs that day. Perhaps you consume 5 g/kg on the other days and 6 or 7 g/kg on this day. Trial and error!

If you have worked out your macros and set your carbs based on available calories, as is the popular and simplest method among most keen gym goers, then consider this. If your kcals are high and your carbs end up being way above that 5 g/kg level, then have a look at your fats. Have you set them too low? 0.6-0.8 g/kg? Why not bump them up to 1 or 1.2 or even the upper end of 1.5 g/kg? Your stomach might thank you for it.

(Of course, for those just looking to improve health and body composition, your carbohydrates can be calculated as the remainder after your protein needs and fat requirements are considered. Endurance performance athletes need to calculate things a little differently)


Of course, everyone is different and when you look at the data that was gathered for the 2012 Tour De France the average intake for riders was 840g with 12 to 13 g/kg being consumed over the 18-hour period between stages (5pm to noon). But, remember a lot of these will be in the form of liquids and gels and probably lots of rice or potatoes in their post-ride meal. However, they would only maintain this for the 3 weeks of the tour and may even go low carb on their rest day.

"... this isn’t Man vs. Food".

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Many ultra-endurance athletes claim to do very well on a low carb and even ketogenic approach. There’s little evidence to the effectiveness of this approach because it’s pretty hard to replicate the adaptations that may be taking place in a clinical environment and the time that it takes for the body to become adequately ‘fat adapted’, which may possibly be as long as 6 months. It’s not just about keto adaptation, there’s a lot of other mechanisms that need to be upregulated.

When you read the evidence it’s easy to dismiss these claims but when you witness an athlete ride for 7 hours on nothing more than a few sips of water you start to question what you know.

But, most people aren’t pro tour cyclists or Ultraman psychos and will fall somewhere in between. It’s also worth noting that some people do struggle to consume the amount of food needed to hit the higher carb targets and some people get an awful lot of gastric upset from that much CHO.

In my experience, it’s rarely necessary for anyone to go higher than 5 g/kg of CHO and, if energy demands are high going a little higher on protein and fats, as I mentioned earlier, fills the gap. The body is quite adaptable and if, your protein is high at 2- 2.5 g/kg then any short comings in your CHO intake may be covered by Gluconeogenesis anyway. If you are a recreational athlete or someone who loves the gym your life isn’t defined by your sport anyway so do you really need to aim for optimal like an elite athlete?

Lastly, let me just touch on the subject of nutrient timing. If you are an endurance based athlete then there are benefits to periods of low carb and low energy training. Although a lot of the evidence on train low principles is still in its infancy athletes have used it for many years in one form or another. Team Sky seem to be the leaders in this research and use various train low practices to optimise their athletes’ adaptations to endurance performance. If your goals are based around body composition and aesthetics then you don’t need to bother, just keep an eye on your 24-hour energy balance and get your protein right.

Summing up

  • Carbohydrates are important for performance and recovery but the exact amount required will vary from athlete to athlete.
  • Sometimes, an athlete will adapt really well to a low carb approach but most don’t. Conversely, some athletes do need a very high amount of carbohydrates but most don’t.
  • Are you an elite athlete or just someone who plays sport at the weekend or like to run/ride in the summer evening? Make your diet fit your lifestyle.
  • The human body is very adaptable but is very vocal so learn to listen to it when it’s trying to tell you something.
  • Periods of low carb training may have benefits in terms of endurance performance but probably isn’t necessary for most active people, especially if you aren’t an endurance athlete.

So in short, don’t be afraid of carbs, but don’t be obsessive about them and stop doing that thing with the bucket of metabolic carnage, this isn’t Man vs. Food.

If you are a recreational athlete and you want to get your diet right for better performance, recovery and balance then hit me up for some online coaching biyatch!


  1. Louise M. Burke. Re-Examining High-Fat Diets for Sports Performance: Did We Call the ‘Nail in the Coffin’ Too Soon? Sports Med (2015) 45 (Suppl 1):S33–S49 DOI 10.1007/s40279-015-0393-9
  2. Kreider et al. Journal of the International Society of Sports Nutrition 2010, 7:7
  3. Potgeiter S. “Sport nutrition: A review of the latest guidelines for exercise and sport nutrition from the American College of Sport Nutrition, the International Olympic Committee and the International Society for Sports Nutrition”. S Afr J Clin Nutr 2013.
  4. Asker E. Jeukendrup (2011) Nutrition for endurance sports: Marathon, triathlon, and road cycling, Journal of Sports Sciences, 29:sup1, S91-S99, DOI: 10.1080/02640414.2011.610348
  5. Santalla, A., Earnest, C., Marroyo, J. A. and Lucia, A. (2012) The tour de France:An updated physiologic review. International Journal of Sports Physiology and Performance, 7 (3). pp. 200-209. ISSN 1555-0265
  6. NUTRITIONAL STRATEGIES FOR THE TOUR DE FRANCE. James P. Morton and J. Marc Fell, United Kingdom
  7. Samuel et al. Fuel for the work required: a practical approach to amalgamating train‐low paradigms for endurance athletes. Physiological Reports May 2016, 4 (10) e12803; DOI:10.14814/phy2.12803