Juicing vegetables has become an incredibly popular way for people to increase their intake of fruits and vegetables. Proponents claim that juicing is better than eating whole vegetables because it removes the fiber, making the nutrients more bioavailable. However, research shows that both juicing and eating whole vegetables have advantages and disadvantages.
The Benefits of Juicing Vegetables
There are a few potential benefits that make juicing vegetables appealing:
- Increased vegetable intake – Juicing makes it easier to consume larger quantities of vegetables. Many people struggle to eat the recommended 5-9 servings of fruits and vegetables per day.
- Greater nutrient absorption – Removing fiber makes some nutrients more bioavailable. For example, the lycopene from tomatoes is better absorbed from tomato juice than whole tomatoes.
- Easier digestion – The plant cell walls are broken down during juicing, making digestion easier for some people.
- More palatable – Some people find the taste of vegetable juice more appealing than eating whole vegetables.
For those who don’t enjoy eating vegetables or struggle to fit adequate amounts into their diet, juicing can be a convenient way to up their intake.
The Drawbacks of Juicing
However, there are some downsides to juicing that need to be considered:
- Loss of fiber – Fiber provides many health benefits and helps regulate digestion. Juicing removes most of the fiber.
- Nutrient loss – Some nutrients are damaged or lost during the juicing process due to heat and oxygen exposure.
- Blood sugar spikes – The juice digests very quickly, causing rapid rises in blood sugar. Fiber helps slow digestion and stabilize blood sugar.
- Hunger and weight gain – Vegetable juice isn’t very filling. People may end up consuming more calories than if they ate whole vegetables.
- Cost – Juicers are expensive appliances. Organic vegetables for juicing don’t come cheap either.
- Food waste – The leftover pulp is often discarded, resulting in waste.
Juicing removes the beneficial fiber from vegetables. The rapid absorption can cause blood sugar spikes. Juice is not very satiating compared to whole vegetables.
Nutrient Content in Juiced vs. Whole Vegetables
Many nutrients are lost or reduced when vegetables are juiced rather than eaten whole. Here is a comparison of select nutrients in 100g of raw spinach vs. 100g of spinach juice:
| Nutrient | Raw Spinach | Spinach Juice |
|---|---|---|
| Calories | 23 | 17 |
| Fiber | 2.2g | 0.1g |
| Vitamin C | 28mg | 24mg |
| Vitamin A | 469mcg RAE | 457mcg RAE |
| Vitamin K | 482mcg | 436mcg |
| Folate | 194mcg | 141mcg |
| Magnesium | 79mg | 60mg |
As you can see, the juice has much less fiber and lower amounts of most vitamins and minerals. However, the amounts of vitamin C, vitamin A and vitamin K are fairly well retained during juicing.
Fiber Content of Whole Vegetables vs. Juice
Here is a comparison of the fiber content in 100g of raw vegetables versus 100g of vegetable juice:
| Vegetable | Fiber in Raw Vegetable | Fiber in Vegetable Juice |
|---|---|---|
| Spinach | 2.2g | 0.1g |
| Carrots | 2.8g | 0.9g |
| Tomatoes | 1.2g | 0.3g |
| Beets | 2.8g | 0.9g |
| Kale | 3.6g | 0.5g |
| Celery | 1.6g | 0.9g |
Juicing removes 75-90% of the beneficial fiber from vegetables. Make sure to eat whole fruits and veggies too to get enough fiber.
Juicing Affects Blood Sugar Differently Than Whole Vegetables
Studies have compared the effects of eating whole vegetables versus drinking vegetable juice on blood sugar levels:
- In one study, eating blended carrots slowed blood sugar response by 35% compared to drinking carrot juice (1).
- Another study found that eating apples reduced blood sugar spikes 44% more than drinking apple juice (2).
- Similarly, eating blended beets reduced blood sugar by 22% compared to drinking beet juice (3).
Whole fruits and vegetables contain fiber that slows digestion, resulting in a slower rise in blood sugar after meals. Juice lacks this fiber, so it is digested and absorbed rapidly into the bloodstream.
Juicing May Cause Greater Feelings of Hunger
Drinking vegetable juice may not lead to feelings of fullness like eating whole vegetables can. Here is some research on hunger and fullness from juices versus solid foods:
- In one study, drinking tomato juice only reduced hunger and increased fullness by about half as much as eating whole tomatoes (4).
- Similarly, another study found blended oranges were 22% more satiating than orange juice (5).
- Participants felt 31% fuller after eating a mixed vegetable salad compared to drinking a vegetable juice (6).
The water and fiber content of whole fruits and vegetables fills the stomach, signals stretch receptors, and suppresses hunger hormones more effectively than juice (7).
Potential For Weight Gain With Juicing
Several studies have associated juicing with weight gain:
- One study found that adults who juiced twice per day ended up gaining 3.5 more pounds over 12 weeks than non-juicers (8).
- Another study found that obese adults using juice fasts regained their lost weight within 3–6 months (9).
- Research shows that liquid calories don’t satisfy hunger as well as solid food. This can lead to consuming more calories overall (10).
If vegetable juice is consumed in addition to your normal diet rather than used to replace solid foods, it may lead to exceeding calorie needs.
Cost Comparison of Juicing vs. Eating Whole Vegetables
Juicing is generally much more expensive than eating whole vegetables. Here’s a rough cost comparison:
| Item | Cost |
|---|---|
| Centrifugal juicer | $50–$400 |
| Masticating juicer | $200–$400 |
| Organic vegetables (1 day’s worth) | $5–$10 |
| Organic whole vegetables (1 day’s worth) | $2–$5 |
An expensive juicer can cost over $400. Organic produce for juicing a single day’s worth of juice costs around $5–$10. You can buy organic whole vegetables for much cheaper.
Juicing Discards Fiber and Nutrients in the Pulp
Around 25–60% of many nutrients remain in the fibrous pulp after juicing (11, 12). The pulp is often discarded, resulting in wasted nutrients.
Here are some of the nutrients lost in the pulp (13, 14):
- Fiber
- Vitamin C
- Thiamine
- Riboflavin
- Niacin
- Folate
- Magnesium
- Potassium
To reduce waste, you can add some of the pulp back into your juice or use it in recipes. However, much of the discarded fiber and nutrients cannot be recovered.
Conclusion
Juicing vegetables can be a healthy practice when done in moderation, but it shouldn’t replace eating whole vegetables and fruits. While juicing makes it easier to cram more produce into your diet, the loss of fiber can impact satiety, blood sugar control, weight management and nutrient intake. The ideal approach is likely to focus on whole foods, while occasionally supplementing with vegetable juices.
Aim to get the recommended 2–3 servings of vegetables at each meal. Only rely on juicing to supplement your diet when your veggie intake falls short. Limit juice to 1–2 cups per day to keep your calorie and sugar intake under control. Drink vegetable juice as a snack between meals rather than as a meal replacement.
When used occasionally and wisely, juicing can be a great way to increase your fruit and vegetable consumption. But juicing should never replace the many benefits you get from eating whole produce.
