Vanessa Hudgens is on the latest cover of Women’s Health, and she revealed to the magazine that she started intermittent fasting a few weeks before her photo shoot.
Intermittent fasting is an overarching term for diets that cycle between periods of fasting and non-fasting over a set period, and Hudgens says she decided to try it after noticing how vibrant a friend was on intermittent fasting. “He is literally pulling a Benjamin Button,” she told the magazine. “Homeboy is aging backward!”
Hudgens says she isn’t doing intermittent fasting to try to lose weight. Instead, she wants to feel healthier. Intermittent fasting isn’t a new concept (other celebrities, like Jenna Jameson and Kourtney Kardashian, also swear by it), but a lot of people still don’t know about it.
Part of the reason seems the be the wide range of eating regimens that qualify as intermittent fasting. Some involve simply not eating after a certain point in the evening and waiting to eat again until a set point in the morning, while others require skipping a meal or whole day of food entirely.
“The idea of intermittent fasting has been around for a long time but more recently has become mainstream,” women’s health expert Jennifer Wider, MD, tells Yahoo Lifestyle. “Intermittent fasting has been shown to increase the body’s sensitivity to insulin (the hormone that regulates blood sugar levels), and a decreased sensitivity to insulin has been linked to obesity, diabetes and heart failure.”
In general, intermittent fasting is “safe-ish,” Gina Keatley, a CDN practicing in New York City, tells Yahoo Lifestyle, noting that most researchers haven’t studied this beyond a month because they’re not sure intermittent fasting is safe or sustainable beyond that. “Most human research on this is centered around relatively healthy volunteers,” she says. “If you’ve got something along the lines of metabolic disease or have disordered eating habits already, then this diet could lead to more problems than solutions.”
The safety of intermittent fasting also depends on factors like “how narrow that window of time is, how many days per week it is, whether there is a caloric restriction also in place on some or all of the days you’re fasting, and whether you have any underlying medical issues or are on a medication that might be contradicted for intermittent fasting,” New York City-based Jessica Cording, RD, tells Yahoo Lifestyle.
In general, experts say intermittent fasting is probably OK for healthy people to try. “A healthy person who wants to explore the potential benefits and finds structure helpful without leading to overly restrictive thought patterns may be a good candidate for intermittent fasting,” Cording says. “But it’s important to be honest with yourself about whether there are any reasons it could be unsafe mentally or physically to attempt this eating pattern.”
Overall, Keatley doesn’t recommend trying this. “The hunger associated with the fasting days does not go away over time, and the long-term impact is unknown,” she says. “Moreover, people experience hyperphagia on this diet, which means you may eat more on your ‘off’ days than normal and not see the results you desire.” Not only that, she says, “it’s really not sustainable long-term [and] there are similar results over longer periods of time with diets that do not make you suffer as much.”
Cording agrees. “I tend to discourage against plans that advise having several days where someone drastically limits their caloric intake,” she says.
If you still want to try intermittent fasting, Cording suggests “starting with a less restrictive approach such as the 16/8 plan where you have an eight-hour fasting period and can drink non-caloric beverages before breakfast and after your last meal.” That “may be a good way to try it out without diving in too deep over your head,” she says.
But Wider stresses that there’s really a lot we don’t know about intermittent fasting right now. “More research is necessary to see if this is viable for long-term benefits,” she says. “The data just isn’t there.”
Read more from Yahoo Lifestyle: