Alcohol can have a dual affect on blood glucose levels for someone with diabetes.
If the drink contains carbohydrate, such as beer and other mixed drinks, the blood glucose levels may rise slightly. However, the overall affect of the alcohol is to lower the blood glucose. So if someone is planning on having one to two drinks it is wise to have them with a meal. When alcohol is consumed in the evening, the bedtime snack becomes extra important to avoid a low blood sugar during the evening or the next morning. When the liver is processing the alcohol, it has a difficult time releasing new glucose and so the chance of delayed hypoglycemia, or a low blood sugar after alcohol intake, is increased.