Kale has become an increasingly popular vegetable in recent years, hailed for its exceptional nutritional value. Some claim that drinking kale juice or smoothies can help with weight loss. But is there any truth to this? Let’s take a closer look at the facts around kale and weight loss.
What is kale?
Kale is a leafy green vegetable that belongs to the brassica family, which also includes cabbage, collards, and broccoli. Its leaves can range in color from dark green to purple. There are several varieties of kale, including curly kale, dinosaur kale, and red Russian kale.
Kale is loaded with nutrients like vitamin K, vitamin A, vitamin C, calcium, potassium, copper, and manganese. It also contains antioxidants like quercetin and kaempferol which have anti-inflammatory effects in the body. Due to its stellar nutritional profile, kale has been associated with many health benefits.
Can drinking kale juice help you lose weight?
Some people claim that drinking kale juice can boost weight loss in several ways:
- Kale is very low in calories yet high in nutrients. Drinking kale juice may help reduce overall calorie intake.
- Kale juice is high in fiber which can promote feelings of fullness and suppress appetite.
- The nutrients in kale, like antioxidants, may boost metabolism and fat burning.
- Kale juice can increase vegetable consumption which is linked to lower body weight.
However, there is limited scientific evidence to support these speculations. No studies have looked specifically at kale juice and weight loss.
Potential benefits of kale for weight loss
Some research suggests kale and other leafy greens may support weight loss in the following ways:
High fiber content
One cup of raw kale contains 2.6 grams of fiber. Fiber moves slowly through the gastrointestinal tract undigested, promoting satiety and curbing overeating. Studies show that increasing dietary fiber can lead to decreased calorie intake and weight loss over time.
Low energy density
Foods with low energy density provide fewer calories per gram. Kale scores a 1.3 on the energy density scale, compared to 4.2 for chocolate. Eating more low energy dense foods allows you to consume a satisfying portion while controlling calories. Studies consistently show that consuming a diet with low energy density supports weight loss.
High water content
Kale consists of about 90% water, making it a very hydrating and low calorie food. Eating foods with high water content has been associated with lower calorie intake and reduced body weight.
Nutrient profile
The vitamins, minerals and antioxidants in kale may also play a role in weight regulation. For example, vitamin C deficiency has been linked to increased body fat and weight gain. Meanwhile, antioxidants like alpha-lipoic acid have been shown to reduce weight gain in animal studies.
Potential downsides of kale for weight loss
While kale does have many nutritional attributes linked to leanness, there could be some potential downsides to consider:
Calorie content
At 36 calories per cup, kale is low in calories. However, juicing removes the fiber and condenses multiple cups worth of kale into a single serving. This increases the calorie density and reduces feelings of fullness compared to whole kale.
High oxalate content
Kale contains oxalic acid, an anti-nutrient that can bind to minerals like calcium, magnesium, and iron in the digestive tract and prevent absorption. People prone to kidney stones may want to limit high-oxalate foods like kale.
Thyroid effects
Kale contains goitrogens, compounds that may impact thyroid function by interfering with iodine uptake. Those with thyroid issues may be sensitive to large amounts of raw kale. Cooking kale appears to reduce goitrogen content.
Nutrient losses from juicing
Juicing kale strips away the fiber and concentrates the sugar and calories. Up to 60% of vitamin C may be lost through juicing as well. Juicing also removes the mass that makes kale so satiating. Overall, juicing likely reduces the potential weight loss benefits of kale.
High portions may be needed
Due to its low calorie density, large portions of kale would be needed to replace higher calorie foods. Eating cups of raw kale is not very realistic or sustainable for most people. Supplementing with small amounts of kale juice is more attainable.
Does science support drinking kale juice for weight loss?
Currently, no direct scientific studies have looked specifically at kale juice and weight loss results. However, some preliminary research provides insights.
In one small study, 20 women drank 12 ounces of low-calorie vegetable juice made primarily from kale, celery, cucumber, and herbs daily for 12 weeks. They lost an average of 3.5 lbs (1.6 kg) compared to the control group and experienced reductions in body fat percentage as well.
A similar study in overweight men and women found that drinking 16 ounces of low-calorie vegetable juice while following a low-calorie diet led to significantly more weight loss over a 12-week period compared to a control group.
In another study, adding kale juice to meals was shown to increase feelings of fullness and decrease hunger more than meals without juice. Though limited, this preliminary research suggests kale juice could potentially have modest benefits for weight management.
However, directly blending kale leaves into smoothies or juices may be preferable to juicing which removes valuable fiber. One study found that weight loss was similar in groups consuming blended fruit and vegetable smoothies versus juice alone. Smoothies retained the fiber, making them more filling.
Potential weight loss results from drinking kale juice
Based on the current evidence, these are some general estimates of the potential weight loss effects of kale juice:
- Drinking 12-16 ounces (1-2 cups) of low-calorie kale juice per day could lead to around 2-4 lbs of weight loss over a 12-week period.
- Drinking kale juice before meals may result in 50-100 fewer calories consumed vs. no pre-meal juice.
- Replacing higher calorie beverages like juice or soda with kale juice containing 25-40 calories per cup could potentially lead to 5-10 pound weight loss over several months.
However, these are just estimates. The actual effects would depend on the individual’s overall diet and lifestyle habits. Kale juice on its own is unlikely to produce dramatic weight loss.
Table summarizing potential kale juice benefits for weight loss:
| Potential Benefit | Impact |
|---|---|
| Low calorie | Reduce overall calorie intake |
| High fiber | Increase satiety |
| High nutrients | Boost metabolism |
| Low energy density | Reduce calorie intake |
| High water content | Decrease calorie consumption |
Tips for losing weight with kale juice
Here are some tips for maximizing weight loss when drinking kale juice:
Consume kale juice 30 minutes before meals
Drinking low-calorie kale juice before eating has been shown to reduce calorie intake at meals.
Blend instead of juice
Blending keeps the fiber from kale intact which lowers the calorie concentration and provides bulk that is satisfying.
Pair with protein and healthy fat
Add nut butter, chia seeds, or protein powder to your kale smoothie to increase satiety even further.
Limit to 1 cup daily
Around 1 cup of kale juice should provide benefits without excess oxalate, calories or goitrogens.
Consume raw
To retain the most nutrients, drink your kale juice right after making it.
Combine with regular diet and exercise
For best results, kale juice should be combined with a healthy diet and active lifestyle.
Other healthy ingredients to add to kale juice
Here are some nutritious additions to consider adding to your kale juice:
Fruits
Apples, berries, pineapple, grapefruit, lemon
Vegetables
Cucumber, celery, spinach, parsley, carrot
Healthy fats
Avocado, chia seeds, flaxseeds, walnuts, almond butter
Herbs and spices
Ginger, cinnamon, turmeric, black pepper, cayenne pepper
Protein
Hemp seeds, pea protein powder, collagen peptides
Playing around with different ingredient combinations can lead to new flavors to enjoy.
Are there downsides to drinking kale juice?
While kale juice may offer some benefits, there are some potential downsides to consider:
- Nutrient loss from juicing – Fiber, vitamin C and antioxidants are reduced
- Oxalate content – Large amounts may be an issue for those prone to kidney stones
- Goitrogens – Could impact thyroid function if consumed excessively
- Gas and bloating – Raw kale can cause GI upset in some people
- Bitter taste – Kale has a strong, bitter flavor that some find unpalatable
To minimize these, blend instead of juice, limit to 1 cup per day, cook kale before juicing, and blend with sweeter ingredients like fruit. Those with thyroid issues or on medications should consult a doctor before adding large amounts of kale.
The bottom line
Incorporating a small amount of kale juice as part of a healthy diet and lifestyle may offer some benefits related to weight regulation. However, kale juice alone is unlikely to lead to dramatic weight loss. Other factors like overall calorie intake, food choices, and physical activity play a much larger role for weight control.
There is still limited evidence on kale juice specifically. While the micronutrients and compounds in kale have properties that may support leanness, juicing removes the fiber which reduces satiety. Blending whole kale leaves into smoothies is likely a better option than juicing.
As with any supplement, it’s a good idea to talk to your doctor before adding kale juice, especially if you have kidney issues or a thyroid disorder.
While kale juice may offer some perks, it should not be viewed as a magic bullet for weight loss. But as part of a balanced, healthy diet focused on whole foods, it could be a beneficial addition for some people looking to shed pounds.
