Should I fast before a workout?

You may have heard people talking about how much fat you can lose if you fast before your work out. But is there any truth to it? Should we really be looking to cut out that pre-exercise nutrition? 

It’s true, there have been a number of studies conducted looking at whether intermittent fasting or fasting before workouts could help you manage or lose weight. However, when you look under the hood, we have found that the size of these types of studies are not large. So while acknowledging that more evidence might prove this theory correct in the future, for now, there’s not enough to support such conclusions. Many of these conclusions also advise people to be cautious about the potential impact fasting before a workout could have on someone in the long term, as well as who this type of training might suit.

Why is nutrition important before exercise? 

Well… no matter what your individual goal is, eating and drinking before your training or event helps your body by:

  • Providing fuel and hydration to give your body the energy it needs for exercise
  • Helping you to sustain quality and intensity for a longer period…especially during repeat efforts
  • Helping to maintain concentration, skill and coordination during your workout (otherwise it can lead to injury, especially if undertaking technical activities like weight lifting, sprinting, trail running etc.)
  • Delaying fatigue – both consciously and subconsciously
  • Reducing the chance of gut upset or extra visits to the loo!
  • Helping to support hunger levels

That’s a whole lot of reasons why planning for appropriate fuelling and hydration is worthwhile!

Having said all this, I’m not going to say that this is for everyone in every situation. Trying to get the right nutrition and fluids in before exercise can be difficult for some and easy for others, and in some circumstances it’s not going to be practical at all. 

So, here are some considerations and some tips to help you prepare for exercise. Everyone has different food preferences and training schedules, so I highly recommend trial and error so you can work out what suits you best in certain situations. Aim for good nutritional habits to fuel your body the way you would fuel your car. And don’t rely on someone to come and find you with a jerry can! 

Woman eating

When is the right time to eat before exercise?

Depending on the type of activity and when during the day you’re working out, timing will differ. The general guide is some time in the two to four hours prior. You want to avoid tummy upset but try not to let it get too far out too. If you’re taking part in an event, you might like to add a small snack closer to 1 hour before the event too. When training first thing in the morning, you might like to include a snack 1 hour before, otherwise make sure you include a quality meal the night before if you’re just not able to get something in.

What should I eat before exercise?

You want to aim to have a meal or snack with these types of features:

  • carbohydrate rich (this gets our fuel stores ready and topped-up, as carbohydrate is the easiest and preferred fuel)
  • low in fat and fibre (fat and fibre slow our digestion of the food so can cause tummy upset)

Examples include:

  • a piece of toast, crumpet or muffin with jam
  • a sliced banana and honey,
  • rice and tuna
  • fruit smoothie (if you tolerate dairy well)

You also want to aim to start your exercise in a well hydrated state – aim for pale coloured urine, it’s a great test. 

This means regularly sipping on water through the day and potentially using electrolytes during your activity if you are exercising for a long period of time or are a heavy and/or salty sweater. Hydration can also impact your performance, so it’s important to make it a priority too.

Remember that it’s worthwhile practising anything you want to do in an event or race during your training. Get your body used to it and apply ‘training’ to your fuelling as well.

Enjoy that flying feeling in your newly nourished exercising state!

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