Don’t say the word diet around Serena Williams.

“Whenever I’m on a diet, I gain weight,” the 43-year-old tennis professional says over the phone from Florida. “I don’t even use the word diet.” Though “the ‘D’ word is a bad word around” her, that doesn’t mean she’s not thinking about her health. It’s quite the opposite, especially since she’s become a mom to Olympia, 7, and Adira, 1.

“Now that I kind of stopped playing tennis, I’ve become so obsessed with being healthy and eating healthy and living healthy, and I have a farm,” she says. Part of that journey has included working with Lingo, a continuous glucose monitor (CGM) from Abbott that tracks blood sugar levels. The gist: Everyone’s bodies responds to certain foods differently, and some research indicates that perhaps even non-diabetics could benefit from watching their blood sugar. The amount of glucose in your body at any given time could swing your mood from one extreme to the other.

More and more people are talking about CGMs for non-diabetics. But not everyone in the health field is so bullish on the prospects of CGMs for everyone, and they question whether the trend is worth the hassle.

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What are CGMs?

CGMs are little sensors placed under the skin of your arm that will send data to your smartphone and offer insights on your blood sugar levels; you wear them for about one to two weeks at a time. It’s a tool diabetics may use, and they can even connect to insulin pumps. They can range in price, and some cost thousands of dollars out of pocket per year; Certain insurers may cover continuous glucose monitoring.

Williams and husband Alexis Ohanian gained valuable insights when eating certain sweets like gelato and pancakes. “I saw that maybe my levels don’t spike as high, and maybe that’s not normal, but maybe that’s my normal,” she says. “But a lot of the stuff, like the gelato, it didn’t necessarily spike my glucose a lot, but I did see pancakes and syrup that did.”

Dr. Robert Shmerling, senior faculty editor of Harvard Health Publishing at Harvard Medical School, previously told USA TODAY he thinks continuous glucose monitoring is marketing getting ahead of the science. If you aren’t diabetic, for example, he says the research doesn’t support CGMs as effective. People who use CGMs – like Williams – may still find them valuable.

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‘We’re all thinking about longevity’

Williams recognizes people take all sorts of paths to better their health. This one just works for her: “Everyone’s talking about, glucose levels, whether they’re doing, the GLPs or whatever. I just thought this was such an interesting way to follow it in in a different way for me. And whatever everyone does is good for them.”

As someone with young kids, she hopes to be vibrant and active with them. “We’re all thinking about longevity and everything that we can have at our fingertips, but longevity is something that we have to work at,” she says. “And so for me, I’m in that journey in my life where I want to work at that, and I want to create the best scenario I can for that.”