Timing of exercise and meals
June 22, 2013
 by Gabe Mirkin, MD

In North America, more than 35 percent of the population
becomes diabetic, and most cases of diabetes could be
prevented with exercise. A high rise in blood sugar
levels causes sugar to stick on the surface of cells.
Once there, the sugar can never get off and is eventually
converted to sorbitol which destroys the cell to causes
all the side effects of diabetes such as heart attacks,
strokes, arteriosclerosis, nerve damage and so forth
(even in people who have not been diagnosed as diabetic).
So anything that prevents frequent high rises in blood
sugar helps to prevent cell damage.

This month, a study showed that exercise lowered high
blood sugar levels in diabetics far more when done after
eating dinner than before eating (Journal of the American
Medical Directors Association, July 2009). Muscle
contractions drive sugar into cells with little or no
insulin. These people were out-of-shape diabetics who
walked slowly and for only 20 minutes. Longer and more
intense exercise lowers insulin and sugar levels even
more and would be even more beneficial.

Another new study shows that you should exercise before
you eat because it lowers blood sugar levels the next
morning (Medicine and Science in Sports and Exercise,
August 2009). Nine healthy postmenopausal women exercised
two hours on a treadmill twice a day. Those who exercised
an hour before meals had a much lower rise in blood sugar
at 16 hours after eating, compared to those who exercised
an hour after their meals. Humans must use their muscles
to stay healthy.

Contracting muscles after eating helps to prevent the
rise in blood sugar that follows meals, and exercising
before eating helps to keep blood sugar levels low the
next morning. Of course many people do not have the time
to exercise both before and after meals, but you will
benefit from exercising whenever you can because lowering
blood sugar and blood fats helps to prolong life and
prevent diseases such as diabetes.