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Intermittent fasting is an approach to eating in which you only eat during a specific time frame and abstain from eating the remainder of the time. Many people practice intermittent fasting to manage their weight, but research shows that it can also help manage blood sugar levels.
We asked our Chief Medical Officer, Sohaib Imtiaz, MD, to explain how intermittent fasting helps support blood sugar control.
*This interview has been edited and condensed for clarity.
Q: Many health-conscious people practice intermittent fasting for weight management. Does it also help stabilize your blood sugar?
Imtiaz: Yes, it does. Intermittent fasting can improve glycemic control and reduce post-meal blood glucose (sugar) spikes in people at risk of developing diabetes and those with diabetes.
People who practice intermittent fasting tend to consume fewer calories, resulting in weight loss, which is one of the primary benefits of this eating approach. Research shows that intermittent fasting can contribute to:
Reduced body weight and fat massDecreased blood glucoseIncreased insulin sensitivity
While we do see an improvement in glucose levels with intermittent fasting, it’s still important to focus on the overall quality of your diet. If you’re doing intermittent fasting but eating an unhealthy diet during your eating window, it won’t do much for your health.
If you have diabetes, it’s important to consult a healthcare provider before trying intermittent fasting. It can cause your glucose to become too low if you’re not eating for long periods, resulting in a hypoglycemic episode.
Why Should I Eat Earlier in the Day?
The key to intermittent fasting is to eat earlier in the day and fast later in the day. Eating late can disrupt your circadian rhythm, a 24-hour cycle your body follows to regulate various body processes, including:
Appetite and digestionHormone release (including insulin, the hormone that helps regulate blood sugar)Sleep patternsTemperature
Much like inconsistent sleep patterns, eating too late can disrupt your circadian rhythm, leading to metabolic imbalances and poor glucose control.
Eating’s impact on your circadian rhythm is why the timing of your meals is crucial.
What Is an Ideal Fasting Window?
A 16-hour fasting window is optimal. The longer the window, the better, because you consume fewer calories. A fasting window of less than eight hours may not have a significant impact.
Some of the most common intermittent fasting windows or “splits” include:
16:8: Fast for 16 hours, with an eating window of eight hours. For example, you may eat between 10:00 am and 6:00 pm.14:10: Fast for 14 hours, with an eating window of 10 hours. For example, you may eat between 8:00 am and 6:00 pm.5:2 split: In a seven-day week, fast for two, nonconsecutive days, and eat following your typical schedule for the remaining five days. For example, you may fast on Tuesday and Thursday, and follow your regular eating schedule for the rest of the week.
