If you decide to fast, it is important to test your blood glucose levels more often as your blood glucose levels may drop too low (known as hypoglycaemia or hypo), particularly if you are unwell and/or are treated with insulin or some diabetes medications – speak to your diabetes team about this. If you experience the symptoms of a hypo, eg feeling shaky, sweaty and disorientated, you must break the fast immediately and treat it with your usual hypo treatment, eg glucose tablets, a sugary drink or GlucoGel, followed by a snack such as a sandwich or a bowl of cereal. If you have to break your fast for any reason, continue your meals as normal for that day and if you’re able you could make up the fast at a later date or provide meals to the needy.
If you have Type 1 diabetes, there is also a danger that your blood glucose levels may run too high (known as hyperglycaemia) and result in a build up of 'ketones'. This could potentially result in a serious condition known as ketoacidosis. The symptoms of high blood glucose levels might include feeling very thirsty, passing a lot of urine and/or extreme tiredness. If your blood glucose levels stay high and you experience these symptoms, speak to your healthcare team.
Before you begin fasting, your diabetes team can also advise you on what to do with your medication and how to keep good diabetes control. For example, your diabetes team may advise you to change the time, type or dose of medication to ensure your blood glucose levels are well controlled.