“Should I eat before or after my workout to keep blood sugar low?”
I am not a doctor and can not compare my knowledge of blood sugar to that of a doctor. As a student of exercise science I certainly learned the close relationship between blood sugar, diet, and exercise.
If blood sugar is a problem you have already made an important step in to controlling a growing health issue in America.
The body prefers to use blood sugar as energy over any other form but when we are inactive and have too much sugar and simple carbohydrates in our diet we can become diabetic.
Since blood sugar is the primary source of fuel for the body a great way to use it is through exercise and physical activity. If our blood is rich with glucose (sugar) it will require insulin to store it or it can be used by the body through movement.
So to answer your question it is better to eat before a workout to keep blood sugar low. Exercising after a sugary meal will at least give the body a chance to use the sugar as energy.
We should never depend on exercise to lower our blood sugar but it is a great way to keep it in check. Consider going for a walk after a heavy meal or avoid sugar later in the day as you become less active.