Sources of information regarding pre-run nutrition can be very confusing. Some will tell you to avoid carbohydrates before your training, while others will tell you they are crucial to your performance. Therefore, the question still stands:
What should you eat before your run?
The source of confusion
In the 1970s, studies observed that eating carbohydrates in the hour before exercise resulted in high blood glucose levels and insulin concentrations 45 minutes after ingestion. At that point, exercise was started. Then, a rapid drop of blood glucose levels was observed because of the high insulin levels combined with the effect of exercise on glucose uptake. Blood glucose concentrations dropped so much that rebound hypoglycaemia occurred.
The symptoms of rebound hypoglycemia include weakness, nausea and dizziness. It is also often assumed that it has a negative impact on performance. One of the early studies reported that performance was reduced when carbohydrates were ingested before exercise compared with a placebo.
Since then, numerous studies have been performed with different experimental designs. This makes comparing the results difficult. Nevertheless, over a hundred studies from all over the world showed either no effect of pre-training carbohydrate feeding on performance or a slight positive one.
Even when hypoglycemia developed, there was no detrimental effect on performance. Also, an interesting finding is that some individuals developed hypoglycaemia in all conditions whereas others never developed it.
Practically, this means that you can consume carbohydrates before exercise as there does not seem to be any detrimental effects on performance. Every individual is different and therefore every athlete will need to develop their own pre-exercise routine that works best for him/her.
Other Simple Tips
- Make sure your nutrition is on point most of the time, not just around your run. The 80/20 rule is a simple way to go about nutrition.
- Keep hydration levels high.
- Caffeine can be a great stimulant to help boost your performance. Even habitual coffee drinkers can benefit from its effects.
- Find what works for you. There is no perfect answer, and trial and error might be needed to determine the best course of actions. This also goes for intra-run nutrition and hydration.
The Key Takeaways :
- Eat what works for you
- Improve your nutrition outside of running times
- Hydration is very important