Adjusting Food for Exercise

An important part of managing diabetes is getting regular exercise. Exercise lowers blood sugar levels. If you take insulin or diabetes pills, your blood sugar may drop too low. Knowing how to control blood sugar levels before, during and after exercise is important. Knowing how to adjust food for exercise will help.

Snack ideas During exercise, you may need some carbohydrates (carbs). If you exercise for more than 1 hour, add a meat serving with the carb.


How do you know if you need to snack? To decide if you need a snack during exercise, consider the following:

  1. The time that your insulin or diabetes pills work the hardest. Try not to exercise when your insulin or diabetes pills are peaking or working the hardest. Ask your doctor when your insulin or pills peak.
  2. Whether or not you have just eaten a meal. Exercise 1-2 hours after eating a meal. This may keep blood sugar from dropping too low.
  3. How long and how hard you will exercise. The longer or harder the exercise, the more sugar the muscles will burn. Keep extra carbs with you to avoid low blood sugar.
  4. Your blood sugar levels. Check blood sugar prior to the exercise. If your blood sugar is less than 100 mg/dL, eat a snack. This will help keep blood sugar from dropping even lower during exercise. People with type 1 diabetes should not exercise if they show ketones in urine or blood.

Are there any special concerns? Low blood sugar may occur for up to 24 hours or even longer, after very intense exercise. To avoid low blood sugar after very hard and long exercise, be sure to adjust your food. Also, check your blood sugar at bedtime. Have a snack if your level is less than 100 mg/dL. Be alert to low blood sugar events for the next 24 - 48 hours.

Important things to remember

  • Before starting an exercise program, talk with your doctor. Avoid exercise if you have type 1 diabetes and you have ketones in your urine or blood. Talk with your diabetes educator or doctor about the right times for you to exercise.
  • Always carry fast-acting carbs to treat low blood sugar.
  • Drink water before, during and after exercise. Always stay well hydrated.
  • Check blood sugar before exercise.
  • Check your blood sugar every hour if your exercise session is longer than 60 minutes.
  • Watch for drops in blood sugar after very long and hard exercise. Eat a snack when you finish. Be sure to check your blood sugar before you go to bed.

How can your doctor help you? Talk with your doctor about safe exercise for your medical condition. Your doctor may want to adjust your diabetes medicine on days that you exercise.