Sipping a green juice makes us feel like we’re doing something really good for our bodies. And when that juice is all – or at least mostly – vegetables, it does have a multitude of health benefits.

Juicing extracts the liquid from vegetables and fruits, leaving behind the fibrous pulp. It takes as much as four to five pounds of vegetables to yield about 16 ounces of juice that is highly concentrated, packing in the nutrients of much more produce than most of us could eat – or want to eat – in one sitting.

Drinking juiced vegetables allows us to incorporate produce that we normally might not like. Beets and kale, for example, tend to be less intense when combined with the flavors of cucumber, lemon and ginger. And vegetables can be easier to digest when they’re juiced versus raw, since our systems don’t have to work as hard to break down the fiber.

The Science of Juicing

Juiced vegetables like beets, spinach and kale can help to improve blood pressure and cholesterol. These benefits are due in part to the antioxidant content of the juices, as well as their anti-inflammatory effects, inhibition of platelet aggregation (reduces incidence of blood clots) and reduction of homocysteine levels, a risk factor for heart disease.

Drinking vegetable juice regularly can positively influence our gut bacteria thanks to the polyphenols in juice, along with oligosaccharides and other prebiotic fibers. These prebiotic fibers are not digested; instead, they pass through our gastrointestinal system intact, supporting the growth of healthy bacteria in our colon. These changes in our microbiome play a vital role in whole-body health.  

Researchers have also tracked general well-being with study participants perceiving their well-being as improved after several weeks of juicing. And anecdotally, people report enhanced energy, focus and mental clarity as a byproduct of regular juicing.

The caveat is that vegetables must be the primary ingredient in order to reap these benefits. Seems obvious, but it’s often not the case.

Many juice blends have names that imply spinach, kale, beets or a host of other ‘superfood’ ingredients but are made with more fruit juice than anything else. They can pack more than 50 grams of sugar into a 16-ounce serving, without offering much in the way of actual vegetables.

It’s easy to know exactly what we’re getting if we’re juicing the vegetables ourselves. But this requires a hefty dose of discipline. We must first stock up on pounds of (preferably organic) produce, spend the time to juice it daily, and then there’s the cleanup time. Not surprisingly, many people opt for ready-made juices, even if it means paying a premium.

Which brings us to the topic of juice bars. Menus can be particularly challenging to navigate, in part because it all seems like it’s good for us.

What’s inside that juice?

Here are seven steps for ordering at your local juice bar, including nutritional landmines to avoid and simple strategies to ensure you’re sipping smart.

Ask how the juice was made. The most common type of juicer is a centrifugal countertop style of machine that has a mesh chamber with sharp teeth that shreds the produce into pulp, explains Julie Nieto Canseco, registered dietitian and Vice President of Operations for Main Squeeze Juice Co., a juice franchise with a dozen locations throughout Louisiana and Texas. 

“These machines spin at a very high speed to separate the juice and the pulp. The downside is that this process creates a significant amount of heat, which destroys heat-sensitive nutrients and enzymes. The juice also oxygenates quickly and ideally should be consumed within 30 minutes for maximum nutrient retention.

Cold press juicers have a two-part process that first shreds the whole produce into a pulp then presses the pulp to extract as much liquid and nutrients as possible, said Canseco. “This method doesn’t introduce heat, which results in a higher nutrient and enzyme profile and also a longer shelf life of up to seven days.”  

Go beyond green.  The colors of vegetables represent the nutrients inside.  Beets and carrots are rich in nutrients like anthocyanins and betalain that you won’t find in leafy greens. If you typically opt for a juice made with greens like spinach, kale and cucumber, try adding purple, red or orange-hued vegetables to boost nutritional density.

Spice it up. In addition to the edible rainbow of colors, add herbs and spices when possible. Ginger and turmeric have a natural anti-inflammatory effect, and herbs like cilantro and basil are rich in polyphenols, antioxidants that protect against cancer, heart disease and diabetes.

Go organic. With juicing, everything is concentrated.  This includes the good stuff like vitamins, minerals, and antioxidants, but it can also mean concentrated amounts of unwanted pesticides and fertilizers. For this reason, organic produce is best, but even if it’s organic, it’s essential to wash it thoroughly. 

Added Sugar. Even the most natural, organic juice bars offer blends that are brimming with sugar. Added sugars may show up on menus as ingredients like honey, turbinado, agave, raw coconut sugar or organic date sugar, with many shops serving up blends with two tablespoons (or more) of these sugars, translating to about 30 grams of added sugar per serving.

Health organizations worldwide recommend limiting our intake of added sugar. The American Heart Association recommends no more than 25 grams per day for women and 38 grams for men. Similarly, the World Health Organization says that no more than 10 percent of calories – and ideally less than 5 percent – should come from added sugar. For a 2,000-calorie diet, 5 percent is roughly 25 grams of added sugar.

The solution: Customize your blend. Request it to be made without added sugars. If you’re not sure, ask. And many juice bars offer plant-based zero-calorie sweeteners like stevia as an alternative to sugary sweeteners.

Dial back the fruit.  We’re not saying that fruit is bad. Far from it. And many of us don’t get nearly enough of it. But the reality is that fruit in the form of juice can pack in more sugary calories than most people need.

Look for juice blends that ideally are made of 100 percent vegetables, or at the very least, 75 percent vegetables. And fruits like lemons or limes are best since they add only a minimal amount of sugar.

Canseco points out that many people are accustomed to juices that are primarily fruit-based, like apple or orange juice. “The popularity of vegetable-fruit blends is on the rise, however, and for good reason. People can now sip a juice blend that that tastes and looks like fruit punch but in reality is a blend of apple, carrot, beet, lemon, and ginger.” And don’t be discouraged if you venture into a juice bar and discover that you only like the lemonade or fruit juices, said Canseco. “This may be an individual’s baseline juice ‘palette,’ but over time we can retrain our taste buds and grow to appreciate juices with more prominent vegetable flavors.”

Timing matters. Maximize your body’s absorption of nutrients by drinking vegetable juice on an empty or semi-empty stomach. I like to drink mine in the afternoon, bridging the energy gap between lunch and dinner.

Keep in mind that freshly-made juices aren’t pasteurized, so they should be consumed within 72 hours after juicing, though immediately after juicing is best to minimize loss of nutrients. For practicality and functionality, juices can be frozen. Just be sure to leave a bit of room at the top of the bottle or jar to allow for expansion when it freezes.

The bottom line: Juicing doesn’t automatically mean “nutritious.” Ask questions about ingredients, and take a look at the nutrition facts if available online or in-store. Don’t be afraid to mix and match to make the vegetable juice blend your own. If you’re going to spend the time, energy and money to incorporate juicing on a regular basis, make sure you’re reaping as much benefit as possible.


  • Molly Kimball, RD, CSSD

    Registered Dietitian + Nutrition Journalist

    Thrive Global

    I’m Molly Kimball, registered dietitian and nutrition journalist with a passion for making it easy for people to live their healthiest, strongest lives possible.  In New Orleans, where the party never stops, that goal can be daunting… but I love every bit of the challenge!    As a Lifestyle Dietitian and a Board Certified Specialist in Sports Dietetics by the Academy of Nutrition and Dietetics, I have managed the nutrition program at Ochsner Fitness Center in New Orleans for more than 20 years, working with thousands of clients ranging from people like you and me, to professional athletes. I’ve learned what drives us, what motivates us, what works and what doesn’t, and what derails even our best intentions. Having the ability to dial into these behaviors and challenges fuels my work in our community and serves as the inspiration for all that I do.  As a writer, I cover all things related to nutrition and wellness, including the new Eat Fit Cookbook, a collection of chef-inspired recipes for the home. I also have been the nutrition expert for New Orleans’ ABC affiliate WGNO since 2009, with weekly TV segments on WGNO’s Good Morning New Orleans, Get Fueled with MollyAnd now you can catch me on my own podcast, FUELED wellness + nutrition with Molly Kimball