Intermittent fasting is an eating plan that switches between fasting and eating on a regular schedule. Research shows that intermittent fasting is a way to manage your weight and prevent — or even reverse — some forms of disease. But how do you do it? And is it safe?
Many diets focus on what to eat, but intermittent fasting is all about when you eat. The plan specifies you only eat during a specific time. Fasting for a certain number of hours each day or eating just one meal a couple days a week, can help your body burn fat. And scientific evidence points to some health benefits, as well.
This diet plan makes intuitive sense. The food we eat is broken down by enzymes in our gut and eventually ends up as molecules in our bloodstream. Carbohydrates, particularly sugars and refined grains (think white flours and rice), are quickly broken down into sugar, which our cells use for energy. If our cells don’t use it all, we store it in our fat cells as, well, fat. But sugar can only enter our cells with insulin, a hormone made in the pancreas. Insulin brings sugar into the fat cells and keeps it there.
Between meals, as long as we don’t snack, our insulin levels will go down and our fat cells can then release their stored sugar, to be used as energy. We lose weight if we let our insulin levels go down. The entire idea of IF is to allow the insulin levels to go down far enough and for long enough that we burn off our fat.
New research is suggesting that not all fasting diets are the same, and some are actually very reasonable, effective, and sustainable. A recent study compared a form of intermittent fasting called “early time-restricted feeding,” where all meals were fit into an early eight-hour period of the day (7 am to 3 pm), or spread out over 12 hours (between 7 am and 7 pm). Both groups maintained their weight (did not gain or lose) but after five weeks, the eight-hours group had dramatically lower insulin levels and significantly improved insulin sensitivity, as well as significantly lower blood pressure. The best part? The eight-hours group also had significantly decreased appetite. They weren’t starving.
Is intermittent fasting safe?
Some people try intermitting fasting for weight management, and others use the method to address chronic conditions such as irritable bowel syndrome, high cholesterol or arthritis. But intermittent fasting isn’t for everyone. Before you try intermittent fasting (or any diet), you should check in with your healthcare practitioner first. Some people should steer clear of trying intermittent fasting:
- Children and teens under age 18.
- Women who are pregnant or breastfeeding.
- People with diabetes or blood sugar problems.
- Those with a history of eating disorders.
People not in these categories who can do intermittent fasting safely can continue the regimen indefinitely. It can be a lifestyle change, one with benefits. Keep in mind that intermittent fasting may have different effects on different people. Talk to your doctor if you start experiencing unusual anxiety, headaches, nausea or other symptoms after you start intermittent fasting.