How much of the spike in blood glucose caused by ingesting sugar is offset by physical activity? I tried to find out by eating a 200 gram bar of milk chocolate (relatively sweet) and then going out and doing what I would call moderate intensity cycling (I don’t have a cycling computer so I don’t have the data on distance covered or average speed).

This is the same chocolate bar I had eaten in a previous test, which had resulted in a peak blood glucose reading of 10.3 mmol/L  (or 185 mg/dL). That test involved fairly minimal physical activity. This time it peaked at 6.3 mmol/L (or 113 mg/dL), a pretty large difference.  Total time spent cycling was 3 hours. Here’s a table of the data.

After 3.5 hours blood glucose was back to where it had started. Here’s a graph showing the gradual rise and fall.

It’s actually a pretty dramatic difference, 6.3 versus 10.3. Physical activity levels really do affect the rate at which our bodies metabolize what we eat. In this case a large dose of sweet chocolate elicits a blood glucose response that would otherwise be associated with a foodstuff containing little sugar or starch.