Juicing is sometimes celebrated as a great way to detox your system or kick start your diet. After all, drinking nothing but nutrient dense fruits and vegetables can't be bad for you, right? Well, it turns out juicing is not exactly the same as including whole food produce into your diet. And while there are some potential benefits of juicing, it might not be the best solution for everyone.
Here's a closer look at the science behind juicing and whether or not you should try a juice diet for weight loss.
What Counts as Juicing?
Juicing is the process of removing the liquid portion from fruits and vegetables, often discarding the pulp, seeds and skin. This can be done by hand or using a machine, like a juicer. Additional herbs and seasonings can also be used, such as ginger, cilantro, parsley, cayenne, cinnamon, etc.
You can also distinguish various juices by the method used to produce them - cold pressed, hand squeezed, raw, pasteurized, and high pressure processing (HPP).
|Types of Pressed Juice|
|Pressed Juice||Most juice is pressed using a centrifugal juice extractor with a fast spinning blade and a mesh filter to remove pulp. However, the speed of the blade can generate heat.|
|Cold Pressed||Juice made from crushing and pressing in a masticating juicer. Eliminates the heat element and potentially yields more juice.|
|Hand Squeezed||Juice squeezed by hand or using a non-mechanical juicer.|
|Raw||Pressed juice that has not undergone any type of pasteurization. Typically has a short shelf life.|
|Pasteurized||The juice is heated to kill any harmful bacteria and extend its shelf life.|
|HPP||This is a type of pasteurization that uses pressure instead of heat.|
Many claim that adding heat or even pasteurization can destroy certain nutrients in the juice. However, there isn't much research to support these claims, and any differences in nutritional value are likely minor (1,2,3). In addition, raw juice has a much shorter shelf life and potential for bacteria exposure.
Juice can be included as part of a balanced diet or in some cases replace food intake altogether. When all other sources of food are eliminated and your intake relies solely on pressed juice for an extended period of time - typically a day or more, this is considered a juice fast. And it is common to see juice cleanses or detox diets sold with a series of specific juices you are supposed to drink during your fast.
Juice fasts are advertised as a way to detox, speed up weight loss, or improve health in various ways. But do these claims have any scientific backing?
Possible Health Benefits of Juicing
There is a difference between including some pressed juice as a part of your normal diet and doing a full-blown juice diet. Regardless, including any form of fruits and vegetables can offer potential health benefits. Here are some of the top reasons why you might consider adding pressed juice to your weight loss plan.
Increased Fruit and Vegetable Intake
Fruits and veggies are some of the most nutrient-dense foods you can eat. They tend to be low in calories and high in many essential vitamins and minerals. They are also associated with numerous health benefits including improved heart health and protection against certain types of cancers (3,4,5).
The juice itself won't promote weight loss, but calorie control will. Veggie juice in particular can be fairly low calorie, and if done right, a juice diet is one way to cut a significant amount of calories out of your diet.
If you are doing a juice fast, you’ll likely lose some weight in the process. But the amount of weight you can lose depends on how long you juice and how well you resume a normal calorie controlled diet once the fast ends.
It is difficult to make substantial changes in your body fat levels in just a few days or even one week, which is why many people will regain the weight as soon as they start eating again. Thus a juice diet can be a temporary weight loss solution or have the potential to kick start a weight loss diet, but the results won't last unless you learn how to cut calories altogether.
Possible Health Concerns of Juicing
The thing is it’s not one food or even one type of food that makes or breaks your health, it a combination of all the dietary choices you make over time. And while fruits and vegetables are often described as “healthy” eating or drinking only produce does not typically result in a balanced, healthy diet.
Here are some of the main reasons why juicing may not be the best solution for fat loss.
The act of juicing removes the fiber from the fruit and veggies leaving you with the liquid-rich extracts that contain mostly water soluble vitamins.
This process also condenses the volume of the produce item, increasing it's caloric density. It is a lot easier to drink four oranges in a 16-ounce cup of juice than eat four oranges in entirety. And the fiber found in whole fruits and veggies is a big part of the reason why. Meaning it may be possible to gain weight from adding too much juice to your diet.
In addition, sticking to just juice, eliminates a lot of important nutrients. While this is likely not a major concern short-term, longer juice fats and frequent might negatively impact your nutrition.
Besides avocado, fruits and veggies are not a source of fat. Fat plays a key role in hormone production, nutrient absorption, nerve function, disease prevention, and healthy skin, hair and nails (8). Not to mention some studies suggest that increasing the intake of certain essential fatty acids, supports better health, improved body composition, and mental and physical performance.
The process of removing pulp, skin and seeds from fruits and vegetables during juicing also removes all of the fiber from the plant. And a number of the positive health benefits of produce are linked to fiber content (9). In addition, fiber is associated with more weight loss in a number of studies due to its supposed satiating effects (10,11).
Fiber is also key for digestive health and you may find yourself feeling more irregular when doing a juice diet.
Essential Vitamins and Minerals
Even though juice can be full of nutrients, it can also be lacking in certain essential nutrients not typically found in fruits and vegetables, like calcium, vitamin D, iron, zinc and vitamin B12. Balanced nutrition is not only key for health, but also plays a role in supporting your weight loss efforts. Your body runs off nutrition, and when it's not getting what it needs from your diet you might find your having hard time controlling your appetite, cravings, mood and calories overall.
Loss of Lean Muscle
Fruits and veggies also lack in protein needed to maintain and repair your lean muscle and support daily bodily functions. Protein is the building block for all of your body’s cells and when you aren’t getting enough from diet, your body tears down your muscle tissue to get what it needs. Including adequate protein also means when calories are low, your body is less likely to tear down precious lean muscle for energy, and instead, uses more body fat.
Unlike vitamin and mineral deficiencies which can take more than a few days to take effect, forgoing protein for numerous days at a time can have an immediate impact on your muscles, especially if you are working out.
High protein diets are also strongly associated with more weight loss in many studies, due to better appetite control, it’s thermogenic effects on food metabolism, and it’s role in supporting muscle (12,13,14).
Increased Hunger and Fatigue
You might find that juicing leaves you feeling pretty weak and tired, not to mention hungry. That's because sticking to a juice only diet, can potentially cut a large amount of calories, but this also means you have less incoming energy to pull from. And less fuel can me no energy for workouts, decreasing your calorie output and physical performance.
In addition, super restrictive diets are associated with increased cravings and reduced willpower - both of which can make dieting that much harder (15).
Poor Blood Sugar Control
Because juice lacks fat and protein, any calories you are consuming are primarily coming from sugars or carbs. And the lack of macro balance in your diet may do a number on your blood sugar control, and may not be a safe diet for diabetics (16).
This is especially true if a majority of the juice you are consuming is made from fruit. Ingredients are listed by weight. So whatever appears first on your juice label is likely going to be the bulk of what you are getting. If increased sugar intake is a concern for you, look for more juices made with primarily vegetable ingredinets - these tend to be lowest in calories and carbs.
With little research supporting juicing for weight loss, it is a wonder why so many self-proclaimed nutrition experts still advocate for juice diets. This has also lead to a lot of misinformation around this approach for losing weight.
Here are some of the common health claims for juicing and why they aren’t backed by science.
Increased Fat Burning
There is no single food that can increase your body’s ability to use fat for energy or speed up your metabolism, including pressed juices. Your body’s metabolism is fairly complex and is difficult to change.
Weight loss ultimately comes down to calorie control and beyond that fact, juicing doesn’t offer any additional fat burning benefits that are supported by research.
If your gut health is suffering it is likely caused by poor dietary and lifestyle choices (17). Eliminating all food for juice can sometimes create an anecdotal effect, leading some to believe it is the juice itself that corrected the problem. In actually, there is no significant research suggesting that any type of juice can promote better gut health or improve digestion over a generally healthy diet.
In fact, the opposite may be true when it comes to digestion since juicing eliminates nearly all fiber from your diet.
Your body is able to remove harmful substances and detox itself on it's own. Juicing has not been shown to support or help speed up this process in any way. In fact, some detox diets can be outright dangerous for your health.
Should You do A Juice Cleanse for Weight Loss?
Currently there is no research showing that juice cleanses are beneficial to weight loss or that they should be recommended at all. Even though it is possible to cut a significant amount of calories by only drinking juice, you could also be missing out on some essential nutrition - like protein, fiber and healthy fats. Not to mention, this type of diet is not sustainable and you might end up gaining all the weight back as soon as you start eating again.
That being said, some juice can be a source of great nutrition and could be an excellent addition to your diet if you are having a hard time getting enough fruits or veggies into your day. Just look for options with more veggies and less calories and sugar overall.
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