The holidays are over, and it’s 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. They’re Dangerous

Beyoncé 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 individual’s 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 Don’t 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, it’s 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 Women’s Health. You might lose a few pounds from just drinking juice all day, but experts say you’ll gain it right back once you stop.

“There’s nothing wrong with going on a juice fast for a few days,” Dr. James Dillard, assistant clinical professor at Columbia University, told WebMD. “But it’s not a great way to lose weight, because you’ll gain it all back.”

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

3. They Aren’t Necessary

People have been detoxing for centuries. “There’s a straight line from detox diets to classical religious fasting,” Harvey Cox, a professor of divinity at Harvard University, told Newsweek.

Fasting and cleanses were historically associated to spiritual enlightenment and atonement, rather than ridding the body of excess pounds and toxins. That’s because the body is designed to detox itself, according to experts.

“The body has its own amazing detoxification systems: the liver and the kidneys,” Ranit Mishori, a faculty member at the Georgetown University School of Medicine, told NPR. “Unless there’s a blockage in one of these organs that do it day and night, there’s absolutely no need to help the body get rid of toxins.” Instead, choose a balanced diet of whole foods, including lean protein, fiber and complex carbohydrates; drink plenty of water; and stay active.

4. They’re Expensive

Detox and juice cleanse programs are not cheap. Top brands such as BluePrint and Juice Press cost at least $60 to $65 per day. Instead of spending hundreds of dollars on a questionable diet fad, go back to basics. Put that money toward a new gym membership plus organic produce and protein from your local grocery store:

  • Leeks contain prebiotics and nutrients that support the body’s “healthy detox.”
  • Sweet potatoes are loaded with fiber and beta carotene, which is a detox-supporting antioxidant.
  • Strawberries are low in calories, high in fiber and naturally sweet, according to physician nutrition specialist Melina Jampolis in Shape.
  • Almonds have the perfect mix of protein and fiber to curb cravings.
  • Cruciferous vegetables such as kale, broccoli, spinach, Brussels sprouts play a role in the body’s detoxification through improving liver, gall bladder and kidney functions. Registered dietician Keri Gans, recommends filling half your dinner plate with these super greens every night, according to Shape.