Pregnancy health

No, you shouldn’t try intermittent fasting while pregnant. Here’s why.

Intermittent fasting, a popular weight-loss method, isn’t appropriate when you’re pregnant. Here’s why.

No, you shouldn’t try intermittent fasting while pregnant. Here’s why.

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In terms of weight loss solutions, it’s simple enough: intermittent fasting (IF) is restricting eating to certain hours of the day (for example, between 10 a.m. and 6 p.m.) and then abstaining from food for an even longer specified amount of time. There are a few ways to do intermittent fasting, the most popular being the 16:8 method, whereby you fast for 16 hours and restrict eating to eight daytime hours. Intermittent fasting has been proven to help people lose weight and may (if the diet is done healthfully) help reduce your risk of Type 2 diabetes and heart disease.

The theory is this: if you restrict eating for long enough, your insulin levels go down and your body will burn fat. Plus, it’s mostly foolproof as a diet method, since you’re keeping an eye on the clock rather than counting calories or calculating carbs and fat. And it seems to work: According to a 2018 study in Nutrition and Healthy Aging, intermittent fasting using the 16:8 method can help people lose up to three percent of their weight in 12 weeks. That said, the people who see the best results from intermittent fasting are also eating a healthy diet, low in sugar and refined carbohydrates, during non-fasting periods.

Intermittent fasting while pregnant

You may have already been intermittent fasting, and since gotten pregnant. Or perhaps you are wondering if it’s a healthy way to eat during pregnancy. But experts say pregnancy isn’t the time for a restrictive diet like IF. “Pregnancy is about nourishment and fueling your body and baby continuously throughout the day,” says Rachel Schwartzman, a naturopathic doctor, who does believe there are some benefits of intermittent fasting outside of pregnancy, such as jump-starting metabolism and improving energy levels. Batya Grundland, family physician at Family Way Obstetrical Group at Women’s College Hospital in Toronto, agrees. “We don’t have evidence or guidelines to support fasting and its safety during pregnancy,” she says. “The goal during pregnancy should be healthy nutrition and lifestyle, not weight loss.”

And while you don’t necessarily need to eat for two, you should increase your calorie intake by a modest amount––aim for an extra 200 to 300 calories per day––and expect to gain 25 to 35 pounds if you have a BMI of 18 to 25. Women with a BMI between 30 to 40 should gain 11 to 20 pounds, and those with a BMI greater than 40 should gain 8 to 10 pounds. “Women should be looking for ways to optimize a healthy lifestyle, including reducing intake of simple sugars and increasing physical activity, but not dieting,” says Grundland.

Also, women who experience common symptoms of nausea, fatigue and low energy throughout pregnancy will want to eat at regular intervals throughout the day, usually every three hours, to stabilize their blood sugar, says Schwartzman.

If you’ve struggled with your body image and are concerned about weight gain during pregnancy, mention this to your health-care practitioner who can provide reassurance and support.

Intermittent fasting while breastfeeding

If you’re breastfeeding, you’ll want to consume even more than when you were pregnant, up to 500 extra calories. Plus, you’re HUNGRY. “One of the risk factors for breastfeeding difficulties and low milk supply is when you don’t eat or drink enough,” says Grundland. Growing and then taking care of a new human is hard work. It’s just not the time to be restrictive about eating.


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