• Megyn Kelly is an NBC host and a former Fox News anchor.
• In her 2016 autobiography, “Settle for More,” Kelly says she doesn’t exercise and focuses instead on maintaining a high-fibre diet.
• Specifically, she adheres to the “F-factor diet,” designed by dietitian Tanya Zuckerbrot.
• There’s science behind the F-factor diet, but it’s not a great idea to cut out exercise completely.

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Like so many of us, Megyn Kelly doesn’t have time to go the gym.

In a small section of her 2016 autobiography, “Settle for More,” Kelly describes how she stays svelte and healthy – and a workout routine isn’t part of her strategy.

Kelly is the host of “Megyn Kelly Today” on NBC, and is a former star anchor on Fox News. In “Settle for More,” she writes, “After I had my children, something had to give, and I gave up on exercise.”

Now, Kelly says, she follows the F-factor diet, from the 2006 book by dietitian Tanya Zuckerbrot. “I started after the birth of my first child, Yates. It took off the baby weight right away,” Kelly writes.

In Zuckerbrot’s book, “The F-Factor Diet: Discover the Secret to Permanent Weight Loss,” she makes the case for a high-fibre diet. She highlights two key benefits of the diet. One, fibre makes you feel full, so you end up eating less. Two, you’re more inclined to stick with the regimen because you’re adding, not eliminating, foods from your diet.

Zuckerbrot explains that all your meals should include high-fibre carbohydrates and lean protein. By the time you complete all three phases of the F-factor diet (each one lasts about two weeks), you should be eating a total of nine servings of high-fibre carbohydrates daily.

There’s compelling research behind the F-factor diet. Zuckerbrot cites one 2009 study, published in the journal Nutritional Review, that found high-fibre, low-fat diets may be more effective for weight loss than low-fat diets alone.

Another study, published 2015 in the journal Annals of Internal Medicine, found that participants who increased their fibre intake to 30 grams or more per day lost as much weight as participants who followed a stricter set of dietary guidelines.

But the role of exercise in weight loss is complicated. One study, published 2012 in the journal PLoS One, suggests that people burn roughly the same amount of energy no matter how physically active they are. In other words, it matters more what you’re putting into your body.

Another, small study, published 2017 in the Journal of Endocrinology, found that increasing the intensity and duration of your workout can help decrease hunger – at least in young men.

All that said, exercise is still an important part of a healthy lifestyle. And Zuckerbrot hardly advises readers to ditch their workouts.

She writes: “Combining the F-factor diet with exercise is the most powerful formula for losing body fat. … Dieting, or reducing your caloric intake, will result in dropping pounds, but keeping the weight off long term is almost impossible.”

Even if, like Kelly, you feel you’re too time-crunched to work out on a regular basis, it’s worth trying to squeeze it in when you can. That’s true whether your goal is weight loss, or simply being your healthiest self.

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