In recent years, keto diets have been increasingly promoted to boost endurance performance. But do they really work and if so, how should athletes use them? Andrew Hamilton looks at the scientific evidence... MORE
Weighty matters: can dietary periodisation optimise your bodyweight?
A few weeks back, I decided to carry out serious groundworks at home. Living in a house on a steep hill (like most other houses in these parts) the rear garden is a good 15ft higher in elevation than the front. And with only a narrow access path on both sides of the house, this meant that the 3 tonnes of stone and stone chippings for the rear garden dropped off by the local builder’s merchant has to be carried by hand from front to rear.
There are two observations at this point: 1) even a fairly small trug of stone chippings is bloody heavy and 2) carrying repeated 25kg-loads of stones uphill qualifies as hard endurance training! As someone who is reasonably accomplished at running up hills, I was surprised that simply walking up to the rear garden carrying these heavy loads raised my heart rate hugely. Indeed, I decided to check and grabbed my heart rate monitor, discovering that my average heart rate was closer to that normally expected when running at a moderate pace on the flat.
The issue of carrying extra weight got me thinking; just how much better would my times be if I could shed a few kilos of extra body fat? Because while I’m in reasonable condition, there’s no denying that compared to very elite runners and top pro cyclists I’m carrying around my own little trug of surplus body fat! It’s also a question that many amateur endurance athletes ponder – especially in sports such as running and cycling where the inescapable force of gravity and the need for a good power-to-weight ratio penalises excess weight mercilessly!
Diet and body fat
Unsurprisingly, your day-to-day dietary patterns and eating habits can play a big role in determining your levels of body fat. This has led some sports nutritionists to suggest that while an athlete’s nutritional strategy should ensure that both training and competition are supported, some thought is given to optimising body composition, which often means shedding a few excess pounds of body fat.
One of these strategies is the use of so-called ‘nutritional periodisation’. This means varying the dietary principles to match the demands of the athletes. An example of this periodisation is to schedule in some training during the early season where carbohydrate is not freely available. While training with low-carbohydrate availability might be detrimental for race performance, it encourages fat burning and can help with fat loss, which in the longer term could improve performance.
One longer-term low-carbohydrate approach that appears to be becoming more popular with athletes trying to increase fat burning is the use of a very low-carbohydrate, high fat diet – also known as the ‘keto diet’. The keto diet turns the conventional wisdom of a high-carbohydrate diet for athletes completely on its head. Instead of a typical 55% carb, 25% fat, 20% protein ratio in a high-carbohydrate diet, a keto diet supplies 75% of its calories from fat, with around 20% from protein and just 5% from carbohydrate!
But do keto diets really work for endurance athletes and if so, how can they be used without harming performance? And are there better, less extreme approaches that can achieve the same objective? These are all questions that are answered in a recent Sports Performance Bulletin article, which looks at what the latest science really says about keto diets, and their benefits or otherwise for endurance athletes. As I’ve explained in the article, media hype is all well and good, but because keto diets are pretty hard to follow, you need to be confident that a) they’ll help your performance and b) you know how to use them correctly. You can read all about the pros and cons of a keto diet – just follow the link below.
There’s no denying that optimising body composition while consuming the correct diet to support racing and training is a hard nut to crack. But take it from someone who’s recently spent numerous hours lugging stones uphill – it could be well worth it!
Andrew Hamilton, Sports Performance Bulletin editor