We would laugh at the latest dieting craze – but perhaps it’s more appropriate to howl.

Meet the Werewolf Diet, reportedly popular among stars such as Demi Moore and Madonna. Also known as the Lunar Diet, it’s true to what its names suggest, and revolves around the cycles of the moon. The plan aims to cleanse your body of toxins and promises you’ll lose up to 6 pounds of water weight a day.

We won’t keep you in suspense: “The only thing that makes sense about this diet is that if you have a very full moon, you may need to trim down,” says registered dietitian Bonnie Taub-Dix, who’s also an Eat+Run blogger. “Any diet that promotes fasting, cleanses or deprivation to this extent is not going to last."

Yet advocates insist that the moon influences the water in our bodies, the same as it does the tides of the ocean. Humans are made up of about 60 percent water, and the thinking goes that when the moon is full or in a new phase, there’s a gravitational pull that affects how much water weight you gain or lose. As the website Moon Connection explains: “By fasting according to the phases of the moon, your body may respond even more powerfully by flushing excess water and toxins from your body.”

In non-werewolf speak, that translates to choosing one of two plans – the basic moon plan or extended version. The basic iteration calls for 24 hours of fasting during the full moon or new moon, when you’re permitted only water and freshly squeezed fruit and vegetable juice.

If you choose to follow the extended version, you’ll need to begin fasting during the full moon and then follow specific eating plans for each of the moon’s phases, which include full moon, waning moon, new moon and waxing moon. During the waxing moon, for example – when you see a slim crescent in the sky – you must eat less than usual and avoid thickeners, such as sweets and fats. You’re also not permitted to eat after 6 p.m., when moonlight becomes more visible. Eating can recommence the next morning.

“It’s a very clever name, and definitely something that’s going to make people sit up and say, ‘What the heck is that?’ Even though it sounds kind of spooky,” says registered dietitian Andrea Giancoli, who’s based in Los Angeles and is a spokeswoman for the Academy of Nutrition and Dietetics. “With that said, it looks like the same old fad diet where you fast and eat certain foods at certain times. It’s just giving it a different spin by basing it on the moon cycles.”

Deciding not to eat after a certain hour, for example, is a popular strategy to control calories – albeit, not typically based on a time as whimsical as lunar events. And Giancoli says we should indeed try to eat our largest meals in the morning, since our appetite tends to increase throughout the day. We're less likely to overeat then, when we're less hungry, than we are in the evening when our appetites are rearing. “People always say they don’t feel like eating breakfast, but that’s the best time to eat because you don’t have a voracious appetite,” she says.

But Giancoli warns that Werewolf dieters shouldn’t bank on dropping 6 pounds in 24 hours. No research supports that claim, and if you do lose weight, it’ll likely be temporary. “You might lose a lot of water weight quickly by not eating, so you’ll see the scale go down in pounds,” she says. “But those pounds aren’t sustainable. If you’re looking for sustainable weight loss, this isn’t the way to do it.”

And as for the best way to lose weight? Forget the werewolves and practice common sense, Giancoli says. The old-fashioned way will do the trick. Opt for balanced meals that emphasize lean protein, whole grains, low-fat dairy and lots of fruits and veggies. Watch your portion sizes. And couple your healthy meals with exercise – ideally, two and a half hours of moderate-intensity activity each week, along with a couple days of muscle-strengthening activities.

But that exercise need not include acting like a werewolf.