Carbohydrates : The Facts !!
The term carbohydrate is synonymous with sports nutrition. The immediate impact of carbohydrate intake (or its absence) on daily training and competition performance has been widely researched and documented. Recent media attention has suggested low carbohydrate diets are beneficial for weight loss and other health benefits. In addition, different approaches to fuelling sports performance has become an item of discussion among scientists ( and the locker room) from time to time. It is no wonder many recreational and elite athletes remain unsure of the amount of carbohydrate they need to support their training and to optimise performance while achieving a weight and body composition that is appropriate for their sport.
Why is carbohydrate important?
Carbohydrate is a key fuel source for exercise, especially during prolonged continuous or high-intensity exercise. The body stores carbohydrate as glycogen in the muscles and liver, however its storage capacity is limited. When these carbohydrate stores are inadequate to meet the fuel needs of an athlete’s training program, the results include fatigue -, reduced ability to train hard, impaired competition performance, and a reduction in immune system function. For these reasons, athletes are encouraged to plan carbohydrate intake around key training sessions and over the whole day according to their carbohydrate requirements as an exercise fuel.
How much carbohydrate do athletes need?
Carbohydrate requirements are dependent on the fuel needs of the athlete’s training and competition program. Exactly how much is required is dependant on the frequency, duration and intensity of the activity. Since activity levels change from day to day, carbohydrate intake should fluctuate to reflect this. On high activity days, carbohydrate intake should be increased to match the increase in activity. This will help to maximise the outcomes from the training sessions and promote recovery between sessions. Alternatively, on low or no training days, carbohydrate intake should be reduced to reflect the decreased training load. A clever way to adjust carbohydrate intake from day to day is to schedule carbohydrate-rich food choices at meals or snacks around the important training sessions. As the sessions increase in their carbohydrate demands, so should the athlete increase their carbohydrate intake before, during or after exercise.
Not only does this strategy help the athlete to keep track of their total carbohydrate needs, but it ensures that the timing of the carbohydrate is best suited to fuel the session.
The table on this page provides some general targets for daily carbohydrate intake goals across a range of activity levels. Each athlete should fine-tune their carbohydrate intake with individual consideration of total energy (kilojoule) needs, specific training demands, and feedback from training performance. Additional guidelines outline the specific ways in which carbohydrate intake can be timed to enhance carbohydrate availability for key sessions.
Which foods are good sources of carbohydrate?
Many everyday foods and fluids contain carbohydrate, but have different features. For this reason, carbohydrate-containing foods and fluids are often divided into categories for comparison. Previously, carbohydrates were classified as either simple or complex, and more recently, the terms low and high glycemic index (GI) are being used (more on GI below). From a sports nutrition point of view, it is more helpful to classify carbohydrates as nutrient-dense, nutrient-poor or high-fat.
|Category||Description||Examples||Use for athletes|
|Nutrient-dense carbohydrate||Foods and fluids that are rich sources of other nutrients including protein, vitamins, minerals, fibre and antioxidants in addition to carbohydrate||Breads and cereals, grains (e.g. pasta, rice), fruit, starchy vegetables (e.g. potato, corn), legumes and sweetened low-fat dairy products||Everyday food that should form the base of an athlete’s diet. Helps to meet other nutrient targets|
|Nutrient-poor carbohydrate||Foods and fluids that contain carbohydrate but minimal or no other nutrients||Soft drink, energy drinks, lollies, carbohydrate gels, sports drink and cordial||Shouldn’t be a major part of the everyday diet but may provide a compact carbohydrate source around training|
|High-fat carbohydrate||Foods that contain carbohydrate but are high in fat||Pastries, cakes, chips (hot and crisps) and chocolate||‘Sometimes’ foods best not consumed around training sessions|
See the carbohydrate ready reckoner for foods that each provide 50g carbohydrate
Daily Needs for Fuel and Recovery:
|Light||Low-intensity or skill-based activities||3–5 g per kg BM|
|Moderate||Moderate exercise programme (~1 hr / day)||5-7 g per kg BM|
|High||Endurance programme (i.e. moderate-to-high intensity exercise of 1-3 hr / day)||6-10 g per kg BM|
|Very High||Extreme commitment (i.e. moderate-to-high intensity exercise of >4-5 hr / day)||8-12 g per kg BM|
Acute Fuelling Strategies:
|General fuelling up||Preparation for events < 90 min exercise||7-12 g/kg per 24 hr as for daily fuel needs|
|Carbohydrate loading||Preparation for events >90 min of sustained/intermittent exercise||36-48 hours of 10-12 g/kg BM per 24 hour|
|Pre-event fuelling||Before exercise > 60 min||1-4 g/kg BM (consumed 1-4 hr pre-competition)|
|During brief exercise
During sustained high-intensity exercise
During endurance exercise including “stop and start” sports
During ultra-endurance exercise
Small amounts including mouth rinse
Up to 90 g/hr using multiple transportable carbohydrates (glucose:fructose mix)
|Speedy refuelling||<8 hr recovery between two fuel demanding sessions||1-1.2 g/kg BM every hour for first 4 hr then resume daily fuel needs|
What about Glycaemic Index?
Glycaemic Index (GI) is a ranking of how quickly carbohydrate foods raise blood glucose levels (BGLs) in the body following ingestion. High GI foods are rapidly digested and absorbed by the body and raise BGLs quickly. Low GI foods, on the other hand, are much slower to be digested and absorbed and result in more gradual rise in blood glucose levels. Refer to the official Glycemic Index website for more information (http://www.glycemicindex.com/).
In sport, it is important to consider immediate requirements and what a whole food or snack can provide (such as protein, vitamins and minerals) rather than looking at only one component of any food. For example, higher GI foods can be useful immediately after exercise to promote a faster recovery of muscle glycogen stores. Daily requirements, based on physique and performance goals should also be considered when making such food choices.
When is carbohydrate important?
An individual’s carbohydrate requirements before, during and after training or competition depend on a number of factors including:
- type, intensity, duration of exercise
- frequency of exercise or time available for recovery between sessions
- body composition goals
- environmental conditions
- training background
- performance goals for the session.
While the recommendations provided above consider the overall carbohydrate needs over the day, it is also important to consider the timing of carbohydrate around training and competition.
Carbohydrate ingestion before exercise should assist in topping up blood glucose levels as well as glycogen stores in the muscle and liver. This is especially important if the competition or training is undertaken first thing in the morning or if the event is high intensity or will continue beyond 90 mins in duration. Refer to Carbohydrate Loading and Eating Before Exercise fact sheets for further information.
The replacement of carbohydrate during prolonged exercise can benefit sports performance, both through effects on the muscle (reducing/delaying the decline in exercise intensity with time) and the brain/central nervous system (reducing/delaying the decline in concentration and mental skills, as well as reducing/delaying the decline in pacing strategies with time). Using specific training sessions to practice consuming specific carbohydrate foods is also important if it is intended to be consumed during a competition.
Carbohydrate intake after exercise is essential for optimum recovery of glycogen stores. Often athletic performance is dependent upon the ability to recover from one session and do it all again in the next session. Incomplete or slow restoration of muscle glycogen stores between training sessions can lead to a reduced ability to train well and a general feeling of fatigue. In competition, it may also reduce subsequent performances where efforts are repeated within or across days (such as in a tournament, a swim or athletics meet, or a rowing regatta). Refer to the Recovery Nutrition fact sheet for more detailed information.
Food Portions Providing 50 g of Carbohydrate
|Wheat biscuit cereal (e.g. Weet Bix)||60g (5 biscuits)|
|‘Light’ breakfast cereal (e.g. Cornflakes)||60 g (2 cups)|
|‘Muesli’ flake breakfast cereal||65 g (1-1.5 cups)|
|Toasted muesli||90 g (1 cup)|
|Porridge – made with milk||350 g (1.3 cups)|
|Porridge – made with water||550 g (2.5 cups)|
|Rolled oats||90 g (1 cup)|
|Bread||100 g (4 slices white or 3 thick wholegrain)|
|Bread rolls||110 g (1 large or 2 medium)|
|Pita and lebanese bread||100 g (2 pita)|
|Chapati||150 g (2.5)|
|English muffin||120 g (2 full muffins)|
|Rice cakes||6 thick or 10 thin|
|Crispbreads and dry biscuits||6 large or 15 small|
|Fruit filled biscuits||5|
|Plain sweet biscuits||8-10|
|Cream filled/chocolate biscuits||6|
|Cake style muffin||115 g (1 large or 2 medium)|
|Pancakes||150 g (2 medium)|
|Scones||125 g (3 medium)|
|Iced fruit bun||105 g (1.5)|
|Croissant||149 g (1.5 large or 2 medium)|
|Rice, boiled||180g (1 cup)|
|Pasta or noodles, boiled||200 g (1.3 cups)|
|Canned spaghetti||440 g (large can)|
|Fruit crumble||1 cup|
|Fruit packed in heavy syrup||280 g (1.3 cups)|
|Fruit stewed/canned in light syrup||520 g (2 cups)|
|Fresh fruit salad||500 g (2.5 cups)|
|Large fruit (mango, pear, grapefruit etc.)||2-3|
|Medium fruit (orange, apple etc.)||3-4|
|Small fruit (nectarine, apricot etc.)||12|
|Grapes||350 g (2 cups)|
|Melon||1,000 g (6 cups)|
|Strawberries||1,800 g (12 cups)|
|Sultanas and raisins||70 g (4 Tbsp)|
|Dried apricots||115 g (22 halves)|
|Potatoes||350 g (1 very large or 3 medium)|
|Sweet potato||350 g (2.5 cups)|
|Corn||300 g (1.2 cups creamed corn or 2 cobs)|
|Green Beans||1,800 g (14 cups)|
|Baked beans||440 g (1 large can)|
|Lentils||400 g (2 cups)|
|Soy beans and kidney beans||400 g (2 cups)|
|Tomato puree||1 litre (4 cups)|
|Pumpkin and peas||700 g (5 cups)|
|Flavoured milk||560 ml|
|Custard||300 g (1.3 cup or half 600 g carton)|
|‘Diet’ yoghurt and natural yoghurt||800 g (4 individual tubs)|
|Flavoured non-fat yoghurt||350 g (2 individual tubs)|
|Ice cream||250 g (10 Tbsp)|
|Fromage frais||400 g (2 tubs)|
|Rice pudding/creamed rice||300 g (1.5 cups)|
|SUGARS and CONFECTIONERY|
|Mars Bar and other 50-60 g bars||1.5 bars|
|Jubes and jelly babies||60 g|
|Pizza||200 g (medium -1/4 thick or 1/3 thin)|
|Lasagne||400 g serve|
|Fried rice||200 g (1.3 cups)|
|Fruit juice – unsweetened||600 ml|
|Fruit juice – sweetened||500 ml|
|Soft drinks and flavoured mineral water||500 ml|
|Fruit smoothie||250-300 ml|
|Sports drink||700 ml|
|Carbohydrate loader supplement||250 ml|
|Liquid meal supplement||250-300 ml|
|Sports bar||1-1.5 bars|
|Sports gels||2 sachets|
|Glucose polymer powder||60 g|
(Source: Peak Performance: training and nutritional strategies for sport J. Hawley and L. Burke. Sydney: Allen & Unwin, 1998).
Written by AIS Sports Nutrition, last updated Feb 2014. © Australian Sports Commission. www.ausport.gov.au/ais/nutrition [/vc_column_text]