Topic Overview

How does alcohol affect diabetes?

When you have diabetes, you need to be careful with alcohol. If you take insulin or pills for diabetes, drinking alcohol may cause low blood sugar.

Too much alcohol can also affect your ability to know when your blood sugar is low and to treat it. Drinking alcohol can make you feel light-headed at first and drowsy as you drink more, both of which may be similar to the symptoms of low blood sugar. Some people confuse low blood sugar with drunkenness, so be sure to wear a medical alert tag and tell people you have diabetes.

Drinking alcohol over a long period of time can cause damage to your liver, called cirrhosis. If this happens, your body may lose its natural response to protect itself from low blood sugar.

If you are controlling your diabetes and don't have other health problems, it may be okay to have a drink once in a while. Learning how alcohol affects your body can help you make the right choices.

How much alcohol can you drink safely?

Work with your doctor or other diabetes expert to find what is best for you. Make sure you know whether it is safe to drink if you are taking insulin or pills.

If you do drink:

  • Check for low blood sugar before you drink. Alcohol can cause low blood sugar for up to 24 hours after drinking, so keep checking your blood sugar. Eating can help, but in some people eating will cause high blood sugar. If you have had trouble keeping your blood sugar in a target range, don't drink.
  • If you take insulin, drinking too much can cause severely low blood sugar. This requires emergency treatment.
  • If you take insulin or sulfonylureas, watch out for low blood sugar that can happen up to 24 hours after drinking alcohol.footnote 2
  • If you have type 1 diabetes, watch out for morning hypoglycemia if you drink 2 or 3 hours after your last evening's meal.footnote 2
  • If you're a man, have no more than 3 standard drinks a day on most days and no more than 15 drinks a week. If you're a woman, have no more than 2 standard drinks a day on most days and no more than 10 drinks a week. A standard drink is:footnote 1
    • One drink is 341 mL (12 fl oz) of beer, 142 mL (5 fl oz) of wine, or 43 mL (1.5 fl oz) liquor.
  • Choose alcoholic drinks wisely. With hard alcohol, use sugar-free mixers, such as water, diet tonic, or club soda. Pick drinks that have less alcohol, including light beer or dry wine. Or add club soda to wine to dilute it. Also remember that most alcoholic drinks have a lot of calories.
  • Check your blood sugar before you go to bed. Have a snack before bed so your blood sugar does not drop while you sleep.

Also remember:

  • Don't drink after exercise. The exercise itself lowers blood sugar.
  • Never drink on an empty stomach. If you do drink alcohol, drink it only with a meal or snack. Having as little as 2 drinks on an empty stomach could lead to low blood sugar.
  • Don't drink at all if:
    • You have problems recognizing the signs of low blood sugar until they become severe.
    • You have nerve damage. Drinking can make it worse and increase the pain, numbness, and other symptoms.



  1. Butt P, et al. (2010). Alcohol and Health in Canada: A Summary of Evidence and Guidelines for Low-Risk Drinking. To be published in Fall 2011.
  2. Canadian Diabetes Association (2009). Alcohol and diabetes: Is alcohol a choice for me? Available online:

Other Works Consulted

  • Canadian Diabetes Association Clinical Practice Guidelines Expert Committee (2013). Canadian Diabetes Association 2013 clinical practice guidelines for the prevention and management of diabetes in Canada. Canadian Journal of Diabetes, 37(Suppl 1). Also available online:


ByHealthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Donald Sproule, MDCM, CCFP - Family Medicine
Specialist Medical Reviewer Rhonda O'Brien, MS, RD, CDE - Certified Diabetes Educator

Current as ofMay 22, 2015