The winter running season is in full swing now but unfortunately for some people this brings with it a lot of unwanted gut problems. Gastro-intestinal symptoms, such as the loss of appetite, heart burn, nausea, vomiting, abdominal cramps and diarrhea are common and effect up to 50% of runners. These symptoms are more likely to occur during sessions which are higher intensity. Most of them can be improved by manipulating your food& fluid intake prior to and during your runs.

Fat & protein

Foods high in fat and protein take longer to get digested than carbohydrate and are more likely to cause heart burn during exercise and should be avoided during the last three hours prior to exercise.

Too much insoluble fibre

There are two main types of fibre – soluble and insoluble.

Insoluble fibre includes things like bran, whole-grains, and wheat. Most fruits and vegetables also contain insoluble fibre. Insoluble fibres draw water into the intestine, increasing the total volume of the intestinal contents and loosening your bowel motions.

Soluble fibre includes things like oats, legumes, barley, citrus fruits and carrots. As these fibres travel through the gut they are mostly metabolized so only a small amount of the ingested fibre is excreted. So opt for porridge instead of Weet-bix before your next long run or race and your stomach will probably feel a lot better.

Not enough water

Gels are often not taken with enough water or washed down with sports drink, both leading to a solution that is too concentrated. This draws water into the intestine increasing the likelihood of dehydration and gastro-intestinal symptoms such as stomach cramps and diarrhea.

Dehydration will also slow the rate at which your stomach empties during and immediately after exercise. Many people find it difficult to drink while running, which isn’t a problem if your run is short. However, if your session is long and you are taking on carbohydrate as well during this time, aim to keep your fluids up as this may help you avoid any nasty gastro-intestinal discomfort.

Everyone faces their own nutritional challenges during training and the same strategies don’t always work for everyone but it is important that you get the basics right first and if problems continue, getting advice from a doctor or sports dietitian is always a good idea.