Fasting and Diabetes
Fasting is an important spiritual aspect for many religions, such as Islam, Catholicism, and Buddhism, as well as for Indigenous people. The practice needs to be considered for certain health conditions. For example, let’s look at Islam. It is estimated that Muslims worldwide account for 1.5 billion people or about 24% of the world’s population. The Islamic month of Ramadan is one of the longest periods of religious fasting. During this time, Muslims abstain from eating, drinking and taking medication from before sunrise to sunset. Ramadan is a lunar-based month, and its duration varies between 29 and 30 days, which falls from May 5 to June 4 in 2019. Depending on the geographical location and season, the duration of the daily fast may range from a few to more than 20 hours. Most people consume two meals per day, one after sunset (Iftar; breaking of the fast meal) and the other before dawn (Suhur; predawn). The Koran exempts the sick from the duty of fasting, especially if fasting might lead to harmful consequences to the individual. People with diabetes fall under this category.
Insulin secretion in healthy individuals is stimulated with eating, which promotes the storage of sugars in the liver and muscle. During fasting, circulating blood sugar levels tend to fall which leads to decreased secretion of insulin. In addition, levels of glucagon (a hormone) and catecholamines (more hormones) rise, stimulating the breakdown of glycogen (sugars that are stored in the body). As fasting continues, glycogen stores become depleted and the low levels of circulating insulin allow increased fatty acid release from fat cells. The oxidation of fatty acids generates ketones which can be used as fuel by our body. In individual without diabetes this mechanism is delicately balanced to help maintain blood sugar concentrations in the physiological range. Those with diabetes, external and internal factors such as medications, poor response to low blood sugars, can impact this process.
Fasting for individuals with diabetes is an important personal decision. Most often, it is recommended to not undertake fasting based on risks of hypoglycemia, hyperglycemia, dehydration and thrombosis.
Hypoglycemia: or low blood sugar, occurs when the levels of sugar in your body drops below normal levels. Longs gaps between meals, certain diabetes medications and alcohol consumption are risk factors. Symptoms include sweating, dizziness, and irritability.
Hyperglycemia: or high blood sugar, occurs when there is too much sugar in your blood. Risk factors include an increase of food or carbohydrate intake or a reduction in medications. Symptoms include weight loss, increased thirst and frequent urination.
Dehydration: or loss of body fluid, can be caused by limited fluid intake. Symptoms of dehydration may include thirst, dry mouth, muscle cramps and heart palpitations.
Thrombosis: or clotting of the blood within a vein. Symptoms include pain, swelling and redness at the blood clot site, a heavy ache, or warm skin in the affected area.
However, for those who are insistent on fasting here are some tips to help you safely fast, using Ramadan as an example.
- Book an appointment with your health care provider. This will help you establish a diabetes management plan you can follow to control your blood sugar levels. It is important for you to understand what you need to do to prepare for the fast as well as how to control your blood sugar levels. Your health care provider will work with you to provide individualized advice to help minimize the risks associated with fasting.
- Establish a healthy diet.For example:
- At Suhur (predawn), try slow-release foods such as 100% whole wheat/grain bread, wild rice and beans.
- At Iftar (after sunset), consume fruits, followed by slow-acting carbohydrates such as brown rice, oats and vegetables.
- Avoid foods high in saturated fats, sodium and sugars.
- Increase your fluid intake during non-fasting hours and especially at Shur and Iftar.
- Breaking the fast. It is important to monitor your diabetes closely and check your blood sugar regularly. Break your fast if your blood sugar is:
- Less than 3.3 mmol/L; or
- Less than 3.9 mmol/L in the first few hours after the start of fasting; or
- Higher than 16.7 mmol/L
Following Ramadan or your fast, it is important to continue to take your medications as prescribed and maintain a healthy balanced lifestyle. You may want to schedule an appointment with your health care provider to discuss your experience managing your diabetes during your fast and make any adjustments to your medications.
Angel Fonseca is a Registered Dietitian and Certified Diabetes Educator at NorWest Community Health Centre.
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