Gastroenteritis causes diarrhea and vomiting, which can lead to dehydration and the loss of sodium and potassium (electrolytes).

The disease puts a stress on your body and often causes an increase in blood glucose (sugar) levels. The two main culprits are stress hormones (cortisol, adrenaline) and lack of physical activity when you are ill. In rare cases, blood glucose (sugar) levels will fall.

What to do if you get gastroenteritis:

  • Measure your blood glucose (sugar) frequently;
  • Continue to take your medication or insulin as usual (or as adjusted by your doctor while you are sick), even if your food intake is reduced because you’ve lost your appetite or are vomiting;
  • Modify your diet: if you find it difficult to eat solid foods, try to eat the usual amount of carbohydrates in liquid form or, at the very least, satisfy your body’s minimum carbohydrate requirements of 150 g per day while you are ill.

What are the signs of dehydration?

Mild to Moderate Dehydration Severe Dehydration       
Dry, sticky mouth Extreme thirst
Unusual sleepiness or tiredness Irritability and confusion
Dry and cool skin Sunken eyes
Headache Dry skin that doesn’t bounce back when you pinch it
Dizziness and lightheadedness Low blood pressure
Rapid heartbeat and breathing
Dark urine in smaller quantity

Call a doctor or go to Emergency if:

  • Signs of severe dehydration;
  • Your blood glucose (sugar) levels are higher than 25 mmol / L accompanied by excessive drowsiness (type 2 diabetes), or 20 mmol / L with a moderate to high ketone level in your urine or blood (type 1 diabetes);
  • You are vomiting continuously and unable to keep liquids down;
  • Your fever stays above 38.5 ºC (101.3 ºF) for more than 48 hours;
  • Diarrhea lasts more than 24 hours or occurs more than 5 times per day.

How to avoid becoming dehydrated

Here are some ways to avoid dehydration and to give your intestines a rest to reduce the diarrhea and vomiting.

Phase 1 Phase 2 Phase 3
Liquid foods

(first 24 hours)

  • Unlimited amounts of water or bouillon, or another non-carbohydrate drink.
  • Drink a rehydrating beverage that provides 10 to 15 g of carbohydrates, every hour.
  • If you have trouble tolerating liquids, drink small amounts every 15 minutes to total at least 15 g of carbohydrates at the end of each hour.
  • Gradually replace the rehydration solution with juice, soft drinks, gelatin, or nutritional supplements (Glucerna®, Boost® Diabetic, etc.).
Solid but easily digested foods

Gradually add solid foods containing carbohydrates, in order to reach the amount of carbohydrates in your daily meal plan.

Back to normal eating

  • Beware of foods that can give you gas: corn, beans and other legumes, cabbage, onions, garlic, raw vegetables.
  • Beware of foods that can irritate your gut: fried foods, spices, chocolate, coffee, colas.

Adapted from: CHUM-Hotel-Dieu Metabolic Medicine Day-care Centre (2013), Understand Your Diabetes and Live a Healty Life, pp.100-102.

Rehydrating drinks

To rehydrate and restore lost electrolytes, especially if you have diarrhea, drink:

  • 1st choice (because of the correct proportions of electrolytes): a commercial rehydrating solution (Gastrolyte® or Pedialyte®)
  • 2nd choice: a homemade rehydrating solution (250 ml (1 cup) of a mixture containing 10 g of carbohydrates):
    • 360 ml (12 oz) of orange juice +
    • 600 ml (20 oz) of water boiled for 1 minute +
    • 2,5 ml (1/2 tsp) of salt