All about carbohydrates & sugar for cyclists

Marine LENEHAN, Sports Nutritionist, Massage Therapist & Yoga Teacher

It is an important goal for athletes of any level to provide their bodies with enough energy to fuel the body to maintain and enhance performance. The body gets energy from carbohydrates, protein and fats. The body’s main source of energy is carbohydrates.

Timing and quantities can have a great impact on performance. Here are a few facts on carbohydrate consumption before, during and after training.

Also, the quality and type of carbohydrates should be considered.

Why eat Carbohydrates?

Carbohydrates are the body’s rocket fuel. Through metabolism, the sugar found in carbohydrates is broken down into ATP, the body’s energy source. Eating carbohydrates before exercise can help restore and maintain glycogen stores, which may be called upon during prolonged training and during competition.

Carbohydrate intake before exercise

A pre-exercise meal has 2 goals, it prevents you from feeling hungry before and during training while optimizing blood glucose levels for the exercising muscles.

3-4 hours before the Competition

700 kcal = 175g carbohydrates

2-3 hours before the Competition

300-400 kcal = 75-100g carbohydrates

1 hour -30 min before Competition

30g carbohydrates

1 hour- 30mn before Training

30g carbohydrates

Carbohydrate intake during exercise

Carbohydrates intake during exercise only increases performance on efforts that are more than 1 hour long. Carbohydrates intake should be prolonged during the whole effort. If the carbohydrates intake is discontinued you become at risk of fatigue and decreased performance. Keeping in mind that carbohydrate fuelling does not prevent fatigue it simply delays it. Your hourly carbohydrates intake is based on your power output.

Carbohydrate intake after exercise

Unless you’re in a stage race or a training camp, you don’t need to take in sugar after your ride. You can wait for a regular meal. If you need to speed up your recovery to be fully ready to ride hard the next day, then a small portion of sugar right after training can help.

10 healthy sources of Carbohydrates



Sweet Potatoes


Brown Rice







5 Carbohydrates before training


Rice cakes





5 Carbohydrate snacks after training

Greek yoghurt with berries & granola

Chia seed pudding

Smoothie Bowl

Fruit salad

Vegetables & hummus


5 Carbohydrates to avoid


White bread

Milk chocolate

Store-bought cereal

Sweetened yogurt

Store-bought fruit juices

The Bottomline

When being mindful of your carbohydrate intake, it’s important to choose highly nutritious foods. Balancing between slow-release and fast-release carbohydrates based on your training load. Consuming a proper amount of carbohydrates and protein after exercise is essential. It stimulates muscle protein synthesis, improves recovery, and enhances performance during your next workout. It is important not to go much longer than a few hours before refuelling with a meal or snack. Finally, replenishing lost water and electrolytes can be the cherry on the cake and help you maximize the benefits of your workout.

Water vs Sports Drinks: what is the best choice?

Marine LENEHAN, Sports Nutritionist, Massage Therapist & Yoga Teacher

The goal of drinking during exercise is to prevent excessive dehydration and changes in electrolyte balance. Hydration is a vital process to athletic performance. After an intense training session, you lose water through sweat, but in fact you lose a lot more than just water. You also deplete the body of carbohydrates and electrolytes such as sodium and potassium. Plain water isn’t enough to replace these nutrients. This is why as athletes we rely on sports drinks instead.

Products such as Powerade, Lucozade & Nuun are designed to replace the electrolytes that are lost during exercise. While
some brands such as MAURTEEN, ENERVIT, BORN, SIS are formulated to replace carbohydrates. This list of brands is of course non exhaustive.

But how to know if you need plain water ? Here is a quick guide on the best hydration solution for you.

What is dehydration?

Water is the most vital element for human health. We can survive a few months without food but only 3 days without water. Getting enough water every day is one of the keys to a healthy performing body. Water helps regulate body temperature, flush body waste,  deliver oxygen, minerals, vitamins & electrolytes  all over the body.

Each day, through our diet, through foods and drinks, we take in water and we lose water through urine, feces, sweat, and breath. Finding balance between the water coming in and going out is key.

General hydration recommendations are 3.5 liters of fluids a day for men and 2.5 liters for women. This includes all liquids even from the food you eat,not just water.

Not getting enough liquids, especially water, can lead to dehydration, which will happen if you have lost too much fluid. Your body won’t be able to perform at its best compromising your training adaptations or your performance. Dehydration can manifest itself through fatigue, dizziness, excessive thirst, dry mouth, a reduced sweat rate, not urinating, dark urine, dry skin, confusion…

Hydration levels can be affected by your training load, environment conditions and altitude. Not having enough water can have negative impacts on both physical and mental performance leading to reduced endurance, increased fatigue, reduced motivation, and increased perceived effort.

Tools to Prevent Dehydration

Water is an optimal choice as it is essential for life. It is no secret that after 3 days without water, the chances of survival are very slim. Water is also the purest source of hydration, present in all our cells with no calories and added sugars. Water is essential to many functions inside our bodies.

  • Helps build and repair every body cell (essential for training adaptations & recovery)
  • Regulates body temperature
  • Helps deliver oxygen throughout the body
  • Lubricates joints
  • Helps with digestion and gastric emptying
  • Helps flush waste through urination and feces
  • Acts as a shock absorber for the brain and spinal cord
  • Helps to absorb sports foods by saliva, to help with chewing and swallowing


When to Choose a Sports Drink

The main purposes of sports drinks are to replenish lost electrolytes and carbohydrates during endurance events. The replacement of carbohydrates is essential to bring energy to the body, being the main fuel source during exercise .They are also the main tool to delay the onset of fatigue & the use of muscle glycogen. When talking about replacing electrolytes : Sodium is the electrolyte superstar when added to drinks during exercise. It can stimulate the delivery of water to the small intestine and help maintain the volume of extracellular fluid. Potassium is added because it helps with muscle contraction during exercise. Drinking fluid during exercise to replace the fluids you lose when you sweat is essential. That way, you’ll reduce the risk of heat stress, maintain normal body function, and maintain performance levels.


An isotonic sports drink is a ‘typical’ sports drink that contains 40-80g of carbohydrate per liter (4-8% carbohydrate solution).

Sodium (NA+)

The body loses an average of 805mg of sodium per liter of sweat loss.

There are only four situations where sports drinks are required.

  1. Sustained exercise lasting longer than 60 minutes

Sports drinks are key for athletes competing or training for more than 1 hour.

  1. Excessive sweat loss

Sports drinks for athletes with high sweat rates are essential as a lot of sodium is lost during exercise.

  1. Exercise in extreme environments, such as high heat and humidity

Sports drinks are key for athletes competing or training in long endurance events in hot conditions.

  1. Excessive clothing is required so more sweat is produced

The Bottom Line

For your easy training days or rest days, hydrating with water is the best option. But if you exercise for 1 hour or more, sweat excessively, or training in hot conditions, a sports drink with carbohydrates, sodium, and potassium is the optimal choice for you.

Working with a sports nutritionist to determine your hydration plan is key to a healthy performing body.

Wicklow 200 Ireland's Premier Cycling Challenge