Sugars and sports performance

This content is authored by Registered Nutritionist Dr Anna Wittekind BSc Nutrition & Dietetics, MSc Sports Science (Fitness & Health), PhD Sports Science, RNutr.

Sugars and sports performance

The 2024 Olympics and Paralympics take place in Paris this summer. The games this year will see nearly 15,000 athletes competing for medals across 50 different sports. By the time the athletes reach the Olympic village, most of the training will have been done and the athletes will be focusing on their final preparations. This will include what and when to eat and drink, to be able to perform at their best. In this article, Registered Nutritionist Dr Anna Wittekind considers whether, and to what extent, sugars might feature in these final preparations.

How and why do carbohydrates, including sugars, fuel sports performance?

Many sports, such as sprinting, tennis or football, rely on performing an activity or skill as quickly as possible, which requires the fast production of energy. One of the fastest fuels we use to provide energy is carbohydrate – mostly in the form of glucose (1). Carbohydrates come from starchy foods (e.g. bread, pasta, rice, and vegetables) and sugars. Sugars come from foods which naturally contain sugars, such as fruits and vegetables and dairy products, and from added sugars such as sucrose (table sugar) or sugars added by manufacturers to foods and drinks. We store carbohydrate in our muscles and liver as glycogen. This glycogen can be called upon to provide energy (glucose) when we need it, and to maintain blood glucose levels. However, these stores are limited and so in longer duration sports, such as field-based team sports (football, hockey) as well as long-distance cycling, marathon running and triathlons, athletes can benefit from taking on board carbohydrate during exercise - that’s if the rules and features of the sport allow for taking in fuel during the event. This carbohydrate can help substitute for, or supplement, our limited internal stores. Once these internal stores run low, we have to rely more on using fat for energy, which can only provide energy at a slower rate.

Guidelines for athletes vs. non-athletes

Current dietary guidelines on sugars differ in terms of the definitions of sugars (total/free/added), the health outcomes on which they are based, as well as whether they make any quantitative recommendations on how much sugar(s) we should consume. Guidelines generally advise that intake of sugars should be limited (2). These guidelines are for populations and may be less applicable to many athletes. Why? Firstly, because of the requirement for the fast provision of energy, which relies heavily on carbohydrate. And secondly, much of the research indicates a high sugars intake may only affect health when in positive energy balance (indicated by weight gain) and/or when relatively sedentary (3–6), both of which may be less applicable to athletes.

Dietary guidelines for sports people

There are different dietary guidelines for sports people which focus on supporting training and performance (7,8). These guidelines include advice on the amount, types and timing of carbohydrate intake, which can include sugars and their food/drink sources, relative to training and performance. They consider the duration and intensity of the sport, including any intermittent nature of the sport, effects of the environment (e.g. altitude or heat) and the time between competitions. In general, in relation to performance the following is advised:

Before the event

In the hours before their event, athletes are advised to consume some carbohydrate. The exact amounts and choices should be driven by prior experience and will vary depending on the timing (how long until the start of the event), the preferences of the athlete and the demands of the event (endurance vs. sprint events).

During the event

During exercise, carbohydrate only needs to be consumed if the duration exceeds approximately an hour. It is unlikely that athletes competing in sports lasting less time will need to consume carbohydrate during their event, although carbohydrate ‘mouth rinsing’ may be recommended to aid performance via positive effects on the central nervous system. During longer duration exercise (endurance exercise typically lasting > 1 hour) recommendations range from consuming 30 to 90 g carbohydrates per hour – the higher rates (>60 g/hour) being applicable to ultra-endurance events lasting more than 2.5 h. Most guidelines propose a ‘food first’ approach in relation to nutrient intake i.e. consume everyday foods and drinks to encourage simultaneous intake of other nutrients. However, the guidelines also recognize that for some sports, or in certain situations, it may be more convenient to consume carbohydrates in supplement form including via drinks, or as bars, gels and confectionery taken alongside water (7). Evidence suggests there is little difference between the form chosen (e.g. drink, bar, gel), in terms of providing a source of carbohydrate (9–12), though athletes also need to consider adequate hydration to support performance. Therefore, the type of foods or drinks consumed is often down to personal choice driven by experience in training and prior competition. Much of the carbohydrates these products contain comes from sugars (sucrose, glucose, fructose) or maltodextrins (glucose polymers) or combinations of these.

After the event

After intense or long-duration exercise, athletes need to re-fuel their glycogen stores in preparation for any subsequent competition, especially when recovery time is short. The exact choices of carbohydrates in terms of form and amount will depend on the time available to refuel and the demands of the subsequent event.

A lady having her teeth checked by the dentist

Did you know?

Just like non-athletes, athletes also need to take care of their teeth. A number of factors may impact on athletes’ need to pay particular attention to their oral health including: the high and frequent carbohydrate intake to support training and performance; the acidic nature of some carbohydrate supplements; and a reduced protection from saliva due to mouth drying (13). Recommendations have been provided to try and limit risk in athletes (14).

So, do athletes not have to worry about sugars intake?

In some sports, a low body mass or fat mass, or a high power-to-weight ratio (a reflection of an athlete's ability to generate power, relative to body weight), can be an advantage. In these sports, athletes will control their total calorie intake via adjustments to intake of carbohydrate, protein and fat to achieve their body composition targets. However, this must be balanced carefully against the need to provide energy to support training and performance (15).

A final word on sugars and sport

Ultimately context is key. The amount of carbohydrates you need to, or can, consume depends on where you are on the physical activity continuum i.e. whether you’re an elite athlete or someone just trying to be more active. The sugars intake alone of a Tour de France cyclist on a race day (using more than 6000 kcal per day with more than 30% of carbohydrate coming from sports drinks) will exceed total calorie requirements for a non-athletic person (16). Guidelines exist not only for athletic performance in general, but also for specific sports disciplines (17,18), and advice can be sought from registered sports nutritionists and dietitians. Meanwhile, people participating in more sedentary or lower intensity sports, such as shooting, golf and archery, or people simply trying to be more active, may be better advised to consume sugars as per appropriate healthy eating guidelines.

References

References

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