Kate Cornell was diagnosed with type 2 diabetes in June of 2005. Since then, she has controlled diabetes through dietary changes, exercise, and, more recently, metformin. She shares her experiences and lessons learned here and on her blog, kates-sweet-success.blogspot.com, which was named as one of the top diabetes blogs for 2015 by Healthline.com.

All people with type 2 diabetes deal with insulin resistance (and some people with type 1 as well). Two ways to improve your insulin action—how well your body uses insulin—are lowering the intake of carbohydrates and adding exercise.

Recent studies discussed in an article on ​DLife.com, made an attempt to figure out which option works best. Is reduced carb intake more effective in lowering blood glucose than added exercise, or is it the other way around?

When we eat carbohydrates, the body will use those carbs for energy immediately, store them for later use as glycogen in our muscles and liver, or, if there is no more storage capacity, they are stored as fat anywhere on the body. People who eat a higher level of carbohydrates more than likely already have full reserves of glycogen and therefore the carbs they eat are stored as fat. This excess fat can increase insulin resistance.

Studies were done that either limited the amount of carbs the participants ate with no added exercise or had them exercise and lower their carb intake. In this case, the added exercise did not improve glucose control more than carb reduction alone (although those who exercised were more fit). In other words, reducing carbs alone made it easier to control blood glucose.

Another study looked at the glycemic index (GI) of the foods eaten. Participants ate the same amount of carbs, but one group ate those on the lower GI side and the others ate higher GI foods. All of them exercised moderately for 60 minutes per day. In this study, the types of carbs didn’t matter and it seemed that the added exercise made the difference in glucose control.

So, is lowering your carb intake better for glucose control, or does added exercise do the trick all by itself?

These studies concluded that lowering your carb intake, regardless of the glycemic index of the carbs, had a greater effect on controlling blood glucose. Exercise has a short-term effect on blood glucose (about 72 hours), so you would need to make added exercise a daily routine in order to see the benefits to your blood glucose.

Carb reduction trumps added exercise for reduction in blood glucose, but both are needed to maintain optimum health.

To learn more on this topic:
Insulin Overdose
Know Your Insulin Options
All You Need to Know about Insulin