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Are your carbs at breakfast affecting your performance?

Training tomorrow morning? Is it good to have something sweet before you exercise in the morning?

You may have seen a good post from @WOD_Science a while back about how carbs in the morning can be detrimental to performance?

Huh? But carbs help high intensity exercise right?

Absolutely, however high GI carbs (🍬) before exercise *can sometimes* have a negative effect on performance because of something called “hypoglycaemia”, where the body removes the sugar from the blood stream causing a crash in energy. This is usually around 1hr after ingesting. Like in the study they looked at (See below, (1)).

However, before dropping the Lucozade, let’s dig a little deeper.

In more recent literature (see below (2)), we see that this has a very minimal impact on actual performance. So even though you may have a sudden drop in blood glucose, this does not necessarily translate into a problem 💡

Takeaways from this second paper:

  1. Hypoglycemia occurred more often when >>> smaller<<<< amounts of carbohydrate were ingested (25g) compared with larger amounts (75g or 200g) 45 min before the start of exercise.

  2. Hypoglycemia was less prevalent when it is ingested just (15 min) before exercise compared with 45 and 75 min before.

  3. Low glycemic index carbohydrates did not cause hypoglycemia. So foods higher in fructose/higher fibre

  4. There was no relation at all between the blood glucose levels and performance.

So even though hypoglycemia may have occurred, it didn’t impact performance.

How does this apply to you?

In short, it’s perfectly ok to consume carbohydrates before exercise, UNLESS it affects YOU. If this is the case, then look to consume carbohydrates earlier on (>2hrs) or immediately before, or swap for low GI sources.

Find what works for YOU as an individual, this is key for any successful nutrition plan.

If you need a little help with your nutrition but really not sure where to start, then book your FREE strategy call with us to give you some direction:

Further reading:

(1) 2002 study -

(2) The myths surrounding pre-exercise feeding -


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