Carbohydrates and Fats

• Daily carbohydrate recommendations for sport

  Based on body weight (not % of energy intake), measured in g/KG
• Daily carbohydrate targets in grams per kg

  • Light - 3-5g
  • Moderate - 5-7g
  • High - 6-10g
  • Very high - 8-12g
• Carbohydrate intake


  • Can be flexible, depending on training and competition needs
  • Periodised approach
  • Fuel for the work required
• Acute feeling strategies


  Promoting high carbohydrate availability to optimal performance in key training session or competition
• Daily carbohydrate recommendations are typically periodised to energy and carbohydrate demands
• On the day of the event

  Main goal is to ensure liver glycogen stores are high ready for performance
• Practically, eating 7-12g per kg of body weight would be an insane amount of food
• Eat a good amount of carbs so during the event it can help with resynthesis
• The more time before the event


  The more carbs can be eaten as the body can digest it
• The less time before the event

  • The less amount of food
  • The lower fat as this will allow for slow absorption
  • The less fibre
• After exercise (before the next training session or competition)

  Priority to replenish muscle glycogen
• Fat availability for energy production

  • Not limited even in leanest of athletes
  • Fat is a fuel source during low- to-moderate intensity aerobic exercise
• Fat recommendations for sport

  • Daily fat intake: 20-35% of total energy intake
  • Proportion of saturated fat limited to less than 10% of energy intake
  • For weight loss/body composition changes, chronic fat intakes <20% of energy intake discouraged
• Functions of fat


  • Fuel source
  • Protection of vital organs
  • Cell membrane constituents
  • Precursors of bile, hormones and steroids
  • Essential fatty acids and fat-soluble vitamin intake
  • Palatability
• Carbohydrates help you exercise for longer than fat would
• • Daily carbohydrate intake targets for athletes reflect a periodised approach, flexible to the demands of training and competition
• • When carbohydrate availability is an important performance determinant, consideration of pre- exercise carbohydrate nutrition is important
• • Dietary fat intake targets for athletes are for the most part in line with public health recommendations
• • No evidence for performance advantage from ketogenic diets
• Carbohydrates are the body's preferred source of energy during exercise. They are stored in the muscles and liver as glycogen and are quickly broken down into glucose
• Low to Moderate Intensity: For longer, less intense activities (like jogging or cycling at a moderate pace), the body predominantly uses fat as a fuel source but still requires a small, steady supply of glucose derived from carbohydrates.
• ATP is the energy currency that powers muscle contractions and other physiological processes necessary during physical activity.
• High Intensity: For short, high-intensity activities (such as sprinting or weightlifting), glycogen is the primary fuel source. The rapid breakdown of glycogen releases glucose, which is then utilized in glycolysis and the Krebs cycle to quickly generate ATP.
• Adequate carbohydrate intake before, during, and after exercise can help maintain glycogen stores, delay the onset of fatigue, and improve endurance and performance
• During prolonged exercise, such as marathons or long cycling events, consuming carbohydrates can provide a critical energy boost 
• Post-exercise carbohydrate consumption is vital for replenishing depleted glycogen stores.
•  This is particularly important in sports involving multiple bouts of activity within a short period, such as during tournaments or training sessions. 
• Quick replenishment ensures that glycogen levels are restored for subsequent activities, aiding in faster recovery and sustained performance.
• Muscles store carbohydrates as glycogen, which is used to generate glucose. Glucose is then broken down to produce adenosine triphosphate (ATP)
• As muscle and liver glycogen deplete leads to fatigue. 
• Carbohydrate depletion is closely linked to the development of fatigue during prolonged physical activity.
•  During prolonged or intense physical activity, these glycogen stores are gradually depleted as they are converted into energy. When glycogen stores are low, the muscle’s capacity to produce ATP diminishes, leading to decreased muscle function and the onset of fatigue.
• As glycogen levels decrease, the efficiency of muscle contractions declines. 
• The shift from glycogen to fats not only reduces the intensity at which an individual can exercise but also increases the perception of effort, making physical activity feel much more challenging.
• Hypoglycaemia, a condition characterized by unusually low blood glucose levels, is a significant indicator of carbohydrate depletion, particularly reflecting liver glycogen stores' depletion.
•  When the body runs low on this crucial fuel, it must shift to other, less efficient energy sources like fat, which takes longer to convert into ATP and is less efficient for high-intensity work
• As exercise continues without sufficient carbohydrate replenishment, liver glycogen stores begin to diminish. Once these stores are significantly depleted, the liver's ability to release glucose into the bloodstream is compromised. This decline in the glucose supply results in hypoglycaemia.
•  Proven that nutrition strategies to improve carbohydrate availability is beneficial to endurance 
• carbohydrate diet needs - 3-5 g/kg/d - light - skill based activities, energy demands aren't high 
• carbohydrate diet needs - 5-7 g/kg/d - moderate - jogging for around an hour a day