The Food Experiment: Fasting and Measuring Ketones

The main goal of intermittent fasting is to switch your body over from primarily burning glucose to primarily burning fat as the primary energy source. This metabolic switch triggers many of the benefits of intermittent fasting related to insulin resistance. The switch typically occurs after about 12 hours of fasting and the switch remains on as long as you don't have any carbohydrates to switch it back off again.

To ensure that you have made the metabolic switch to fat burning, we find it useful to have our patients measure ketones in their urine. This can be done by picking up a urine dip stick at the pharmacy (they are sold over the counter) and dipping it in your urine. If the urine shows more than trace to 1+ ketones, then you have made the switch to fat burning.