But if those plans include the Isagenix diet , experts say you may want to reconsider.

What is the Isagenix diet?

In a nutshell, the Isagenix diet incorporates aspects of fasting and meal-replacement plans. Followers are asked to mostly eschew real and whole foods in favor of packaged shakes, bars, supplements, and other Isagenix-branded products.

There are several different Isagenix systems to pick from, depending on whether your goal is to improve your energy and performance or start your weight loss journey. (The Isagenix site is careful to frame all its products as weight management aids-as opposed to weight-loss products.) The companys basic pitch is that by ditching most real foods in favor of Isagenixs assorted shakes and shots, youll lose unhealthy weight, feel more energetic, and detoxify your body.

You accomplish this by combining shake days and cleanse days, says Mike Roussell, PhD, a nutrition scientist and co-founder of Neutein , a company that makes brain health supplements. On shake days, youd replace breakfast and lunch with Isagenix shakes, Isagenix snacks, and a variety of supplements, he explains. Then youd prepare your own dinner featuring lean proteins, fruits and vegetables, and a very small amount of fat from healthy oils.

On cleanse days, youd swig several shots of an antioxidant-rich Isagenix concoction, chew some Isagenix tablets, and eat little to no food, he says.

Whats the problem with all this? Aside from the usual fatigue, nausea, and potential constipation seen with most calorie-restricted, shake-based dietary approaches, the biggest risk is loss of lean body mass, Roussell says. He explains that the Isagenix diets protein intakes are likely insufficient to support muscle growth and maintenance.

Furthermore, there is no scientific data to suggest that consuming concentrated antioxidants improves the detoxification capacity of your body, he says. Thus the supplementation protocol likely has no impact on weight loss or your bodys detoxification pathways.

In fact, overdoing it on antioxidants could be harmful. Back in the 1990s, some promising research linking the antioxidant beta-carotene to lower rates of lung cancer led to a large-scale study in which smokers at risk for lung cancer took large quantities of beta-carotene supplements. The result? Lung cancer rates skyrocketed -prompting the researchers to cut the study short. Turns out, antioxidants can in some cases turn into pro-oxidants if the body has too much of them. And this can fire up some of the bodys cancer pathways.

Its exactly this kind of finding that has led most nutrition experts to push people away from ingredient-overloaded shakes and supplements and toward whole-food diets. Also, the various Isagenix plans all feature or promote low-fat eating, which many experts now say is unhelpful for sustained energy and weight loss.

The highly restrictive nature of some of the Isagenix weight-management plans could also be problematic, says Jeanne Tiberio, MS, a registered dietician and wellness coach with Varsity Tutors .

Tiberio says she has concerns that the diet could trigger refeeding syndrome, which is a cluster of symptoms caused by metabolic disturbances and malnutrition. She mentions abnormal heart rhythm, confusion, and convulsions as possible side-effects.

On the bright side, she says the meal replacement shakes are a perfectly fine way to get your nutrient needs met while on the go, and could result in weight loss if you simply replace a single meal with one of the shakes." But, she adds, the contents of the Isagenix shakes are similar to Boost and other liquid meal replacement shakes on the market. The big difference: the Isagenix shakes are a lot pricier. Depending on where you buy Isagenix products, a 30-day supply can cost upwards of $400.

There is no reason to buy into the hype, Roussell says of the Isagenix diet. Using meal replacement shakes to cut calories to elicit weight loss is a strategy that has been employed for decades. Furthermore, the Isagenix plan calls for near round-the-clock eating-a grazing style that research says can stoke your appetite and so may promote weight gain.

Take a step back and squint, and the Isagenix diet looks like a mashup of outdated eating fads and failed nutrition science.

If your current diet is a mixture of fast food and energy drinks, then pretty much any switch-including to an Isagenix plan-could do you some good. But youd be much better off now and in the long run adopting a healthy whole-foods based diet.

So save yourself money and disappointment, and pass on the Isagenix diet. Something like the Mediterranean diet is the way to go.