One of the top goals that people have when embarking on a juice fast is to lose weight. Juicing is the only natural food way to get more nutrition with fewer calories. By consuming a fresh vegetable and fruit juice in place of meals you can cut your caloric intake and encourage weight loss while providing your body with nutrition and energy.

But juicing can help you lose weight in another way – by changing your microbiome for the better.

According to research, fresh juices can alter your intestinal microbiota – increasing the good bacteria associated low body weight, and decreasing the bacteria associated with obesity.

Health Benefit of Vegetable/Fruit Juice-Based Diet: Role of Microbiome Study

In this study, conducted by the Center for Human Nutrition at University of California, researchers acknowledged the importance of gut microbiota to human health. They knew that vegetable and fruit juices provide polyphenols, oligosaccharides, soluble fiber and nitrate which can have a prebiotic effect.

But there hadn’t been much research on the health benefits of fresh juice, so they put a 3-day juice based diet (juice fast, juice cleanse) to the test.

They enrolled twenty healthy adults into the study. These were people that were used to eating at least 3 servings of fruits and vegetables a day, and had not been on antibiotics or laxatives in the previous 2 months.

Participants consumed six 16-ounce juice blends (they included a nut milk) a day for 3 days. Total caloric intake was 1310 kcal per day. The beverages provided 28 grams of fat, (which was 20% of calories from fat, largely due to the nut milk,) and 28 grams of fiber.

Here is exactly what they drank:

  • Green 1: apple, cucumber, celery, romaine, lemon, spinach, kale and parsley
  • Green 2: (same ingredients as above, with the addition of ginger)
  • Root: beet, apple, lemon, ginger
  • Citrus: apple, pineapple, lemon and mint
  • Lemon Cayenne Water
  • Vanilla Almond Milk: Almond milk with dates, sea salt and vanilla bean

After the juice fast, participants returned to their usual diet with the same number of fruit and vegetable servings as before the fast.

Blood, urine and stool samples were collected at baseline, and on day 4 and day 17.

Here’s how the study turned out.

Body Weight and Composition

The 3-day juice fast resulted in a significant decrease in body weight, 3.75 ± 2.65 lbs. (1.7 ± 1.2 kg.) This may not seem like much, but the juice fast was only 3 days, and this is generally what I see with my clients – weight loss of about a pound a day when juicing only or juicing and eating 1 cleanse-style meal a day.

After 2 weeks, body weight remained decreased by about 2 pounds, (0.91 ± 0.9 kg.) And I would estimate that about a pound of their regained weight was colon weight, not fat.

Something more was going on than just calorie-deficit induced weight loss. They were consuming about 1300 calories a day. This is a 500-calorie deficit for someone consuming about 1800 calories a day to maintain their body weight. Normally a person would have to maintain a 500-calorie deficit for an entire week to lose just 1 pound. Yet they lost a pound a day and maintained most of that weight loss two weeks later.

The “something more” was significant changes in their gut bacteria.

Juicing and Your Gut Microbiome

According the researchers, the two most abundant bacteria in the human gut are Firmicutes (40-60%) and Bacteroidetes (20-40%.)

  • Firmicutes are associated with increased body weight.
  • Bacteroidetes are associated with lean bodies.

In just 3 days, “Firmicutes was significantly decreased, while Bacteroidetes was significantly increased when comparing end of juice based diet (day 4) to baseline.”

Microbiome Changes with Juicing

The soluble fiber, including pectin and xylans from fruit and vegetables, feed human Bacteroides species bacteria, resulting in a significant increase in these species.

Other Juice Benefits

In other studies, Bacteroides was associated with a decrease in cholesterol, blood pressure and other markers of metabolic syndrome.

In this study, researchers also noted a significant increase in plasma and urine nitric oxide (NO.) Nitric oxide is important for healthy arteries and a healthy heart. Lack of NO promotes stiffening and hardening of the arteries, and increased blood pressure. The dark leafy greens and beetroot in the juices are sources of NO.

Nitric Oxide Boosted by Juicing

The high polyphenol content of the juices provided antioxidant protection for lipids. When LDL is oxidized it can produce inflammation that leads to disease and organ damage. Oxidized LDL is bad for heart health. The polyphenols in fruits, vegetables (and their juices) greatly reduce oxidation, improving cardiovascular health.

Lipid peroxidation was determined by the analysis of urine malondialdehyde (MDA). Urine MDA was significantly decreased by 40% in 6-hour urine collected at day 4 compared to baseline urine (p = 0.01) and returned to baseline levels at day 17

Effect of juice based diet on urinary malondialdehyde concentration. Data are mean ± SEM. One way repeat measures ANOVA was performed. The difference to baseline is indicated **p < 0.001.

The Takeaway

This study clearly showed that juicing induces significant changes in the intestinal microbiota associated with weight loss. Juices also significantly increased serum and urine NO and decreased LDL oxidation.

I often hear juicing naysayers claim that you have to eat the whole fruit or vegetable to get the benefits. That discarding the insoluble fiber is tantamount to a crime. While I definitely encourage the consumption of whole fruits and vegetables, fresh juice has many proven health benefits.

Juicing – even if you only drink them in place of one or two meals a day, or as a supplement – can help you lose weight and maintain that weight loss. It can also improve your heart health, lowering cholesterol and blood pressure.

What’s Next?

As part of my 6-week Juicy Plant-Based KickStart coaching program, I use my juice therapy education and experience to help clients establish a daily juice practice that works for them. I also guide them through a customized and doable juice fast or modified juice cleanse with meals. It is usually 5 days, but we can do shorter or longer based on the client’s goals. Clients lose about 1 pound a day during this period. More importantly, they learn how to make and enjoy delicious whole food plant-based meals so that they can continue to lose weight and improve their heart health without calorie counting, crazy workouts or going hungry. It’s about setting the foundation for the last diet you will ever need – a way of eating – a lifestyle – that is delicious, nutritious, and sustainable.  

So, if you are interested in getting my support, click here to book a time on my calendar. I can’t wait to speak with you and learn about your health goals and help you get started!

Source: Henning, S.M., Yang, J., Shao, P. et al. Health benefit of vegetable/fruit juice-based diet: Role of microbiome. Sci Rep 7, 2167 (2017).