Sports Nutrition: What To Eat When Before And After Exercise

1 Oct

A client told me recently, when I asked what exercise they did, that they longed to begin exercising but that they couldn’t.

Something was stopping them.

They didn’t know how to change their diet in response to, and how to fit food in around, their workouts.

I figured that this client couldn’t be the only person feeling that way.  And it’s no surprise.  We tend to make everything sport-related a little difficult, confusing, and complicated… everything from selecting the best pair of running trainers, to the correct whey protein, to the sports drink bottles is a little like working through a minefield.

Hopefully this blog post can explain what to eat, and when , before and after you exercise.  [If it doesn’t answer your questions, feel free to drop me a line and I’ll be happy to help.]

So, here goes…

Before Exercise

The Importance of Pre-Exercise Eating

Eating shortly before you exercise has several benefits, including:

  1. It helps to prevent hypoglycemia (low blood sugar) which interferes with exercise performance and causes symptoms including lightheadedness, needless fatigue, blurred vision and indecisiveness
  2. It helps settle your stomach, absorbs gastric juices and abates hunger
  3. It fuels your muscles by providing stored glycogen
  4. It gives you the peace of mind of knowing that your body is well fueled for the exercise

Pre-Exercise Foods

Remember that this is general advice, and some people will find that this advice does not suit their metabolisms.  However, as a general rule, the majority of people see good results when they eat 0.5g carbohydrates for every pound of their body weight, one hour before beginning moderately hard exercise, and 2g carbohydrates per pound of body weight four hours before.

This might sound a bit technical – and sometimes people imagine that this works out at a huge amount of food – but it’s pretty easy to work out.

For a person weighing 150 pounds, this is 75g of carbohydrate an hour before they exercise, which can easily be obtained from a small bowl of cereal and a banana.

However, it’s worth remembering that if you are doing intense, very hard exercise, any pre-exercise food is likely to remain undigested – typically, the body will only digest food during a workout if you are exercising at a pace that you can maintain for more than 30 minutes.  Therefore, when you are planning your meals around your physical activity, take into consideration the pace of your exercise and, for intense activities, have a hearty meal as calculated above four hour before the exercise but don’t have the smaller, pre-exercise snack an hour before.

There are several other factors to consider when deciding whether to have the small, pre-exercise snack, including:

  • Experience – novices tend to experience more gastrointestinal problems following pre-exercise snacks
  • Age – younger athletes often do not handle pre-exercise snacks as well as older counterparts, perhaps because of the older people’s experience
  • Gender – gastrointestinal problems during exercise affect women more, especially around the time of menstruation
  • Emotions – food will remain in the stomach undigested longer when you are tense
  • Caffeine – caffeine intake before exercise increases the incidence of gastrointestinal problems (remember that caffeine is not just found in coffee, but also in energy drinks, some tablets and chocolate)

After Exercise

Generally speaking, if you are a recreational exerciser perhaps using the gym or swimming a few times a week, your post-exercise diet shouldn’t be a cause for concern, simply because your body has sufficient time to refuel before your next workout.

If you are an athlete doing 2 or more workouts a day, however, your post-exercise diet is crucial, and your first priority should be replacing the fluids lost during the workout.  Good options for doing this are low GI sports drinks, water, and watery foods such as watermelon or soups.

Tip: To calculate how much fluid you have lost during a workout, simply weigh yourself before and after.  Ideally you should have lost no more than 2% of your body weight during the exercise.  And you’ll know when you have replaced the lost fluid because your urine will be clear or pale yellow and you will be urinating frequently – this can take up to 48 hours.

Next, to replenish your muscle glycogen, you should consume carbohydrate-rich foods within 15 minutes of completing your workout.  This is to ensure you catch the period when the enzymes responsible for making glycogen are most active and will most rapidly replace the depleted glycogen.

You should aim for 0.5g of carbohydrate per pound of body weight every hour, consumed at 30-minute intervals for four to five hours.

Your body will naturally want this amount, if not more, but note that consuming above this calculation will not hasten the recovery process.

But what about protein, I hear you cry.

You don’t have to avoid protein in your recovery diet and a small amount can in fact enhance glycogen replacement (although this is disputed).  The amino acids provided from the protein may also assist with building and repairing muscles.

Through sweat, you will also have lost electrolytes, minerals in the body such as potassium.  These will easily be replaced from your recovery diet – good sources of potassium include potato, yoghurt, orange juice, banana, pineapple juice, and raisins.

For more information about sports nutrition, pre- and post-exercise foods and healthy sports drinks just contact me.


6 Responses to “Sports Nutrition: What To Eat When Before And After Exercise”

  1. Gary King October 1, 2010 at 3:24 pm #

    Great advice there Katie. I try to plan my workouts for the same time everyday so that I get into the routine of eating at the same time. However, I don’t beat myself up if I don’t get it right every time.

    I also have a really effective method to ensure that I stay hydrated – when I feel thirsty I drink some water!

    • Katie Williams October 4, 2010 at 12:47 pm #

      Thanks Gary, glad you liked it

      That’s a great tip to plan workouts around the same time, but also not to stress too much when that isn’t possible.. life gets in the way sometimes 😉

      And as long as your workouts are less than an hour long, water’s a great choice for hydrating you


  2. Jillybean October 1, 2010 at 10:07 pm #

    Thanks Katie – another great article. I have recently found coconut water. This is also really good for replenishing electrolytes!

    • Katie Williams October 4, 2010 at 12:45 pm #

      You’re welcome Jill, glad you liked it

      Coconut water is a great choice – more electrolytes than most sports drinks and more potassium than a banana!

      Have a great day,

  3. Ken October 4, 2010 at 4:19 am #

    Thank you. I will be sure to pass this onto my athletes.

    • Katie Williams October 4, 2010 at 12:44 pm #

      You’re welcome Ken, glad you liked it and hope your athletes do too.

      Thanks for taking the time to comment


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