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Eating Carbs and Exercise

Before you decide what you should eat before exercise you need to decide what strategy you are on? What do I mean by strategy? For example are you eating for:

* Performance
* Maintenance
* Weight loss

All 3 of these strategies require different food intakes.

Performance assumes that you need to be at your Max for Glycogen and Protein levels, this means in effect you will have to consider your intake of food (mainly carbs) some time before your event, if the event is an endurance event at Zones 4 – 5 (up to 2 hours in duration) you will need to ensure that your Glycogen levels are fully topped up as the likelihood that your body will be using Glycogen as its major energy source.

If you are taking part in an endurance event over 2 hours at a lower zone 2 – 4 for the most part you still want to begin with full Glycogen levels but will need to have a strategy for your carbohydrate intake during the event.

In effect this will be the same strategy for Maintenance, Maintenance being a high consideration when taking part in multi day events or multi discipline events or if you are training every day for a period of time.

So eating for Performance can begin many days before the event depending on how efficient your body is at restoring your Glycogen levels, this is something that you will learn about your body over time, in fact it can take some people up to 7 days to fully replenish your Glycogen levels.

What are my current Glycogen levels?

You can establish how much Glycogen that you have in your system by weighing yourself, the average dude carry’s about 500G of Glycogen and a similar amount of water, this is the first thing to deplete during a 2 – 4 hour exercise period, this is the weight you will need to replace, its not an exact science but you will get a feel for it.

A good start is to assume that you need a couple of days input of carbs to begin with to top up your Glycogen levels, in this instance you will need to begin by eating LOW GI foods, as you get nearer to the beginning of the event start to look at foods that have a high energy content KC per gram, for example an 5 apples will have a very high carbohydrate value but also has a high fibre content, in other words a pure apple juice will be much easier to consume than a litre of apple juice, a similar pattern can be seen with fresh apricots and grapes, high carbs and high fibres, dried fruit and apricots same Carbohydrate value but much easier to eat due to lower fibre.

Before Exercise

Most studies recommend that you intake 1 gram of carbohydrate for every KG of weight, if you weigh 50KG then 50G of carbohydrate is required, this is best taken as a small meal 1 hour before exercise begins, again this should be LOW GI foods.

Low GI foods digest much more slowly and therefore release slowly over time during the exercise therefore providing a source of food for longer (however modern studies have found little proof of this helping except to make the athlete feel fuller for longer).

If you prefer to have a large meal prior to exercising then you should wait 2-4 hours before exercising and this food should be LOW GI.

You will be advised to experiment during training to find out what works out best for you!

During Exercise

More importantly what do I need to eat during endurance exercise as if your event is non endurance and you are performing at zone 4 – 5 you will primarily be using Glycogen and probably have enough to last if you start fully topped up and you are not doing multiple days of this, however Gels and power bars may help along with Carb drinks.

Its is recommended that you eat between 50 – 60 grams of Carbohydrate per hour during exercise, (if you have a Garmin set an alert for every hour) these carbs should be MEDIUM to HIGH GI foods that are easily absorbed into the bloodstream, Gels, Power bars and sports drinks being the obvious candidates.

Don’t close your eyes to more natural foods such as dried fruit, Soreen etc, look through the GI food chart and be creative, once again look for the most bang for your buck, eat high KC (energy values) for each gram dried fruit being a great example.

Its is recommended that you begin eating 30 minutes into an exercise and then at hourly intervals, this ties in with the maximum amount of of Glycogen that the muscles can absorb.

In fact you can begin eating HIGH GI foods 15 minutes before you begin exercising as its unlikely in that period you will get an insulin spike dud to the time it takes to ingest.

Don’t forget that recovery begins during the current exercise, the more you are able to keep your Glycogen levels up the better shape you will be in for the next days exercise as always recovery for tomorrow begins NOW!

Eating After Exercise

Its generally accepted that 60g – 100 grams of carbohydrates are required very quickly after exercise as your body is at its most receptive to replenishment (the 2 hour post exercise window) approx. 150% higher this then rapidly decreases to only 4 times the normal rate. This is due to an insulin release and the fact that during this window muscle membrane is more permeable and can take in more glucose than normal.

The amount you need to eat is dependent on the following factors:

* How depleted your Glycogen stores are
* The extent of your muscle damage
* The amount and the timing of the carbohydrates you eat
* Your training and fitness levels.

Weight Training for example has a high impact on your muscle and fibre damage therefore your glycogen replenishment could take up to 7 – 10 days.

1 Gram for every KG you weigh in the first 2 hours then every 2 hours until your next main meal, try to make these carbs full of goodness also grains and minerals.

HIGH – MEDIUM GI foods in order to speed absorption, mix these carbs with protein where possible (see blog on proteins).

Plan your meals and snacks accordingly for recovery!

If you train daily your carbohydrate intake will need to be high, in the region 500 – 600grams per day, failure to do this will result in an inability to train hard to your potential and a depletion of Glycogen.


1Gram of Carbohydrate for every KG you weigh

Post exercise window is 2 – 6 hours 1 G for every KG every hour HI GI Foods

50 – 60 grams per hour during exercise of HI GI foods

50 – 100G of LOW GI foods prior to exercise

50 – 100G of LOW GI foods post exercise (depending on muscle damage and intensity)

LOW GI Foods in between Workouts

In-between Workouts

Once you have exhausted the 6 hour post workout window you should switch back to slow burning low GI foods, these foods will help you stay feeling full and prevent you from snacking unnecessarily.

See blog on how much carbohydrate you should eat per day.

Timings put simply!
> 2 Hours Prior to exercise = Low GI Foods
> 15 Minutes Prior to exercise = HI GI foods can be eaten as there is not enough time for an Insulin Release
>< During Exercise = HI GI and MED GI foods
2 < After exercise = HI GI
2-6 <After Exercise = HI GI Eat in 50 – 60 g portions
6 < After Exercise = LOW GI FOODS

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