The holidays are over, and its time to get back on track after weeks of so-called cheat days. Many people will jump on the detox bandwagon, drinking green juice for days on end, but dietary experts say these popular cleanses are not the solution to kick-start your 2015 weight loss goals. Below are four reasons why you should not do a juice cleanse in the new year.

1. Theyre Dangerous

Beyonc Knowles shed 20 pounds in two weeks on the Master Cleanse diet for her role in the movie Dreamgirls. We all want to look like Queen Bey, but sticking to a liquid diet of water, lemon juice, maple syrup and cayenne pepper is actually unsafe.

Most juice cleanses have a calorie intake of less than 1,000 calories per day, which puts the body in starvation mode in order to preserve energy, according to experts. Depriving your body of essential nutrients can also cause dizziness, nausea, constipation, fatigue and irritability.

Cutting out complete food groups in the long term may have adverse effects on an individuals health, Claire Williamson, a nutrition scientist at the British Nutrition Foundation, told BBC News. A healthy calorie intake varies from person to person, but the American College of Sports Medicine recommends women eat at least 1,200 calories per day and men eat at least 1,800.

2. They Dont Work

Celebs such as Gwyneth Paltrow and Nicole Richie have praised the benefits of juice cleanses, including weight loss. But restricting calories and cutting out entire food groups can actually do the complete opposite, according to experts.

Although juice contains beneficial antioxidants, its also packed with sugar and lacks the fiber and protein in whole produce that fills you up, Jaclyn London, a senior dietician at Mount Sinai Hospital in New York City, told Womens Health. You might lose a few pounds from just drinking juice all day, but experts say youll gain it right back once you stop.

Theres nothing wrong with going on a juice fast for a few days, Dr. James Dillard, assistant clinical professor at Columbia University, told WebMD. But its not a great way to lose weight, because youll gain it all back.

Heavily restricting your calorie and nutrient intake slows the bodys metabolism. So, not only will you gain back the weight you lost and then some but itll be even harder to lose it again. In the long run, thatll sabotage your weight-control efforts, Katherine Zeratsky, a registered dietitian at Mayo Clinic, told MyHealthNewsDaily.

Read more:

New Year, New You: Are Juice Cleanses, Detox Diets Healthy?