By Brianna Elliott

Juicing is an easy way to consume lots of nutrients without having to eat whole fruits and vegetables. Many people claim it's a helpful weight loss tool.

The juicing diet trend has increased in popularity over the years, but its effectiveness is controversial.

Juicing is an easy way to consume lots of nutrients without having to eat whole fruits and vegetables. iStock

This article will explore whether juicing can really help you lose weight.

What Is Juicing?

Juicing is the process of extracting the liquid from fruits and vegetables, while removing the solids. This can be done by hand or with a motor-driven juicer.

The juice from fruits and vegetables doesn't contain any skin, seeds or pulp. It does contain some nutrients and antioxidants, but without the beneficial fiber of whole fruits and vegetables.

Some people use juicing as a so-called "detox" method. However, there are no scientific studies showing that replacing solid food with juice will detoxify the body.

Your body is able to get rid of toxins on its own through the liver and kidneys, so using juice as a detox treatment is completely unnecessary.

People also use juices as nutrition supplements and to lose weight. Neither of these uses is supported by research, but many people claim they work.

In general, juice recipes contain fruit and vegetables. Many also contain spices such as turmeric and ginger.

Bottom Line: Juicing involves extracting the liquid from fruits and vegetables. People drink this juice to "detox" their bodies, add nutrients to their diets and lose weight.

Juice Diets

There are several types of juice diets available. The most common type is a juice fast, in which people replace their meals with juiced fruits and vegetables.

The point is to lose weight by abstaining from solid food, while still ingesting a significant amount of nutrients from the juice.

Generally, the diets are very low in calories.

Some people do juice fasts for just a few days, while others go on them for weeks at a time.

Unfortunately, the effectiveness of juice diets is not well studied, but many people claim they produce quick weight loss.

Bottom Line: The most common juice diet is a juice fast, in which people consume juice instead of solid foods in an effort to lose weight.

Juicing May Significantly Reduce Calorie Intake

To lose weight, you must maintain a calorie deficit, which means you consume fewer calories than you burn (1, 2, 3).

Most juice diets lack solid food and consist of about 600–1,000 calories per day. This results in a large calorie deficit for many people, so juice diets do often lead to weight loss, at least in the short-term.

The fewer calories you consume on a juice diet, the more rapidly you'll lose weight.

However, once your calorie intake goes back to normal after the juice diet, you'll likely regain some of the weight, if not all.

Bottom Line: Juice diets tend to be low in calories and the resulting calorie deficit may lead to rapid weight loss.

Juicing Diets and Fullness

Since juice-only diets lack solid foods, you might find yourself feeling hungrier than usual when following this type of regimen.

The reason for this is because liquid meals are less filling than solid foods, especially when they are high in carbs. This effect has been confirmed by several studies (4, 5).

In one study, 20 normal-weight adults and 20 overweight adults were each given 300 calories worth of apple, apple sauce or apple juice with a meal or as a snack (6).

Those who drank the apple juice were less full than those who ate the solid foods. They also ended up hungry again earlier than the others.

Solid foods are more filling because they contain fiber and protein, which are both important nutrients that have appetite-reducing properties.

Fiber has the ability to reduce appetite because it may slow down the emptying of the stomach and increase digestion time (7, 8).

Meanwhile, protein changes hormones that signal fullness, which are essential for appetite regulation (9).

Individuals who consume adequate amounts of fiber and protein tend to eat less and weigh less than those who don't (10, 11, 12, 13).

The juicing process eliminates fiber from fruits and vegetables. These sources are also naturally low in protein. Therefore, juice diets may not fill you up and, for that reason, they can be difficult to sustain.

Bottom Line: Juice diets may be unsatisfying because they lack solid foods, fiber and protein, which are important for inducing feelings of fullness.

Juicing Affects Metabolism

The severe calorie deficit that many juice diets cause can have a destructive effect on your metabolism.

These diets are characterized by rapid weight loss and limited protein intake, which may lead to reduced muscle mass (14).

Muscles are metabolically active, so individuals with a lower muscle mass have a lower resting energy expenditure. This means they burn fewer calories at rest than those with more muscle (15, 16, 17).

Additionally, your body senses starvation when you dramatically reduce your calorie intake, so your body acts to preserve calories by burning fewer of them.

Controlled studies have confirmed this effect in individuals who follow calorie-restricted diets (18, 19, 20).

In one study, overweight and obese women underwent a calorie restriction treatment for three months. They experienced a significant reduction in resting energy expenditure over that period (20).

The same effect occurred in another study where participants consumed either 1,114 or 1,462 calories per day.

Participants who underwent the lower-calorie treatment experienced significant decreases in resting energy expenditure after only four days (19).

In fact, the group that severely restricted their calorie intake experienced a 13 percent drop in resting energy expenditure. That's double the drop observed in the group that only moderately restricted their calorie intake (19).

It is clear that calorie restriction can reduce metabolism after just a few days.

While a calorie deficit is necessary for weight loss, it appears that low-calorie diets, including juice fasts, may be counterproductive due to their negative effects on metabolism.

Bottom Line: Juice diets may negatively impact your metabolism, especially when they are very low in calories and you follow them for a long time.

Juicing Can Be Harmful to Your Health

Juicing is generally safe if you do it for only a few days at a time. However, juice fasts do carry some risks when they are prolonged.

Inadequate Fiber

Whole fruits and vegetables are excellent sources of fiber, but that fiber is removed in the juicing process.

Fiber is an essential part of a healthy diet. Eating enough of it is important for optimal digestion because it keeps the beneficial bacteria in your gut healthy and may reduce constipation for some people (21).

Additionally, it may lower your risk of heart disease, diabetes and obesity (21).

By juicing, you significantly reduce your fiber intake, which may result in health consequences.

Nutrient Deficiencies

There are a few reasons why doing juice fasts for long periods of time may lead to nutrient deficiencies.

Since these diets lack animal products, they are low in a few essential nutrients, such as calcium, vitamin D, iron, vitamin B12 and zinc.

All of these nutrients have important functions in the body. Inadequate consumption may lead to conditions including osteoporosis and anemia.

Juice fasts are also low in omega-3 fatty acids, which are healthy fats that fight inflammation and contribute to brain and heart health (22, 23).

Not only are these diets low in specific nutrients, but they may actually interfere with the absorption of the nutrients.

One reason for this is that juice diets tend to be low in fat, which is required for the absorption of the fat-soluble vitamins A, D, E and K (24, 25, 26, 27).

Additionally, some raw vegetables often used in juicing contain an antinutrient called oxalate, which can bind to minerals in the body and prevent them from being absorbed (28).

Oxalate-rich vegetables that are commonly used in juicing include spinach, beet greens, kale, beets, Swiss chard and turnip greens.

Increased Risk of Infection

Due to the minimal protein and inadequate amounts of some important nutrients in a juice diet, following one for a long time can impact the immune system and increase the risk of infection (29, 30).

Studies show that even a mild depletion of immune-enhancing nutrients, such as iron and zinc, may impair immune system health (31).

When your immune system is compromised, you may catch illnesses such as colds and the flu more easily. It may also take longer for your body to heal wounds (32).

Fatigue and Weakness

Fatigue and weakness are common side effects of following a juice fast.

These symptoms are likely to occur because of the low number of calories these diets contain. If you're depriving your body of calories, you're essentially depriving it of energy, which can lead to these undesirable effects.

Reduced Lean Muscle Mass

The minimal amount of protein in most juice fasts may lead to a reduction in lean muscle mass, which can have a negative impact on health.

As your lean muscle mass decreases, your metabolism decreases as well, meaning you will burn fewer calories and may have a more difficult time maintaining weight loss (15, 16, 17).

Bottom Line: Juicing is generally safe, but following a juice-only diet for a long time may have a negative effect on your health and well-being.

Does Juicing Help You Lose Weight?

There is not any formal research to support that juicing helps with weight loss.

Based on anecdotal evidence, it is clear that juice diets may lead to rapid weight loss in the short term, especially when the diet is very low in calories.

However, you could experience some negative health consequences of such severe calorie restriction, especially if you follow the diet for more than a few days at a time.

Additionally, it is difficult to sustain such restrictive diets. Most people do not stick with very-low-calorie diets for long and end up gaining back the weight they lost.

Juicing may be an easy way to lose weight quickly, but it appears that its potential health consequences may outweigh its benefits.

You are better off following a more sustainable diet that includes whole foods and enough calories to keep your body functioning properly.

Reposted with permission from our media associate Authority Nutrition.