Pre-Workout Nutrition: Fuelling For Intensity and Duration

How Important is Pre-Workout Nutrition Strategy?

Whilst providing adequate energy to support the demands of a training session is the primary aim of pre-workout fuelling, its influence on training stimulus and intensity runs deeper. 

Early research positively identified that carbohydrates directly influence:

• Time to fatigue 
• Exercise intensity 
• Overall exercise performance (e.g. race times)

Simply put… Better Fuel = Better Output 

Think of it like filling up your car before a long drive - starting with a full fuel tank allows you to reach your destination efficiently, while starting on empty may mean struggling to make it - or running out of energy all together. 

So, Do You Always Need a Pre-Workout Meal?

In most cases, yes. However, this depends on a variety of factors:

• How long is your training? 
• At what intensity are you completing it? 
• What is the goal of the session (training stimulus)?

Intensity vs Duration 

Traditional fuelling guidelines suggest pre-workout carbohydrate intake becomes important when exercise duration exceeds 60 minutes. 

Whilst this is a great start, it still leaves some questions unanswered. If we go by the book, anything under 60 minutes doesn’t need to be fuelled, right? Not quite. 

Yes, Duration is important and longer sessions lead to:

• A larger total energy expenditure 
• Depleted liver and muscle glycogen levels  
• Increased reliance on exogenous carbohydrate (gels/bars/chews)
  

This is why pre-workout fuelling is highly recommended for sessions lasting longer than 60 minutes. 

But, Intensity is also a key factor. 

As exercise intensity increases, the body relies more on carbohydrates as its primary energy source. This is especially evident during demanding efforts such as race-pace intervals, threshold training, high-volume strength sessions, and events like 5-10 km races.

Because carbohydrates can be broken down rapidly to meet high energy demands, these sessions rely heavily on muscle glycogen (the body’s store of carbohydrate). When glycogen availability is low, performance can suffer, leading to earlier fatigue, reduced power output, and a decline in overall training quality.

This means that even when a session is shorter than 60 minutes, performance may still benefit from pre-workout carbohydrate intake, particularly if the session is high in intensity.

The key takeaway - It’s not just about how long you’ll be training, it's also about how hard. 

Timing: When Should You Eat?

The general recommendation is to consume 1 to 4 grams of carbohydrate per kilogram of bodyweight in the 1 to 4 hours before your exercise begins (Burke et al., 2011). It follows that the closer you are eating to your training starting, the fewer grams of carbohydrate you should consume.

For example: a 70 kg athlete should aim to eat between 140 and 210 grams of carbohydrate when eating 2-3 hours before their session (2-3 g/kg).  

To keep it simple:

• Further away from training, eat a larger meal 
• Closer to training, eat a smaller meal / medium snack
• Within 60 minutes of training, opt for simple + easy to digest carb sources (e.g. energy gel, sweets, honey) 

What Should You Eat?

Carbohydrates are your main priority here.

Typically stick to easy-to-digest high GI foods, especially as you get closer to exercising. For example, a couple of rice cakes, sports drinks or an energy gel. 

Protein may be useful but not always necessary.

Protein isn't our priority pre-workout, however it can be useful scenario-dependent. For instance, in periods of energy deficit (fat loss/cutting phases) and/or to support muscle protein balance. 

Our advice is to keep protein light, around 20-30g in meals 3-4 hours away from training. For example, a chicken or turkey breast sandwich on white bread. 

Fat: Keep it low!

High fat meals pre-workout are a one-way ticket to a poor session as they can:

• Slow digestion 
• Delay gastric emptying 
• Increase the risk of gastrointestinal issues

Steer clear of fatty cuts of meat, creamy or cheesy dishes, rich sauces, and fried or oily foods.

Fibre should also be kept low to reduce the risk of gastrointestinal discomfort, cramping and bloating during training.

To limit this, opt only for light salads and avoid bulky vegetables like broccoli, cauliflower in your pre-workout meal as well as nuts, seeds and wholegrains (oats, brown rice or pasta). These are better choices in your post-workout meal or snack. 

The key takeaway here is HIGH Carb, MODERATE Protein, LOW Fat.

Example:

2-3 Hours Before: White rice, lean protein source, handful of light, non-bulky veg (i.e. mixed salad leaves, tomatoes, cucumber)

30-60 Minutes Before: 2-3 rice cakes with honey or 500ml sports drink/fruit juice

What About Fasted Training?

If you train early in the morning is it okay to skip breakfast and get straight out for your session? Or should you force that piece of toast down before you start your day?

More recent research has explored the use of fasted training and how it can stimulate metabolic adaptation such as improved fat oxidation rates and increased mitochondria size. Whilst this may seem appealing to some athletes, it’s key to use fasted training in a specific and periodic manner, not as a replacement for proper fuelling.

What Are The Limitations?

• Intensity limited to ~65% VO₂ max
• Reduced training duration
• Consistently training fasted can increase the risk of chronic energy deficit and fatigue
• Can lead to injury and/or illness if poorly managed or mis-used
  

When To Use It?

• Early morning, short duration, low-intensity (Zone 2) sessions
• Strategically, not daily 

Fasted training can be a useful tool but for most athletes key sessions need fuel to promote meaningful adaptation and performance outcomes.

Hydration

Hydration should be kept simple. In the hours leading up to training, a fluid intake of 5-10 ml/kg bodyweight is recommended. For a 70 kg athlete, this is approximately ~500 ml of fluid consumed based on 7.5 ml/kg.

For most daily training sessions electrolytes aren’t required, with our regular food intake often providing sufficient electrolytes. However, when choosing to exercise in hot conditions or if you would identify yourself as a heavy sweater, additional electrolytes can support hydration and help maintain fluid balance. 

Putting It All Together

Pre-workout nutrition should be tailored to the demands of the session, with a focus on providing sufficient carbohydrate to support performance. Don’t just fuel for duration, fuel for the work you’re asking your body to do.

Fasted training should be used strategically, and is best reserved for shorter duration, lower intensity sessions (Zone 1-2), where energy demands aren’t as high and performance is less reliant on carbohydrate availability.

Closer to training, avoid high-fat, high-fibre, and unfamiliar foods, as well as excessively large meals. This helps minimise the risk of gastrointestinal discomfort and supports optimal performance. Opt for easy-to-digest, simple carbohydrates to provide the body with a quick, readily available source of energy, helping you sustain intensity and delay fatigue during your workout.