There are many dietary strategies people adopt for losing weight and improving overall health, including juice fasting and ketosis diets. However, these two don't really go together. To get into ketosis, you need to keep your carb intake very low, but most juices are high in carbs. You do have a few low-carb juice cleanse options, though, if you decide to give juice fasting a try.
Setting the Stage for Ketosis
Ketosis is a natural metabolic state that occurs when the body doesn't have glucose from carbs to use as energy. In the absence of glucose, the body begins to break down fats, releasing substances called ketones that can be used as an alternate source of energy. The key to getting into and staying in ketosis is keeping your carb intake very low.
There are a few ways people achieve ketosis. Fasting is one way. Whether giving up food altogether or doing intermittent fasting, the body will go into ketosis when its store of glucose is used up. These methods can get you into ketosis for a short period of time, but once you eat enough carbs, you'll no longer be in ketosis.
The ketogenic diet is another method. On a keto diet, you decrease your carbs as low as 20 grams per day and increase your fat intake significantly. You don't need fat to get into ketosis, but certain fats, such as caprylic acid, can expedite the process, according to a research review published in PeerJ in March 2018.
The addition of fat on a keto diet also has effects on the sustainability and longevity of the diet. Because fats are satiating, they can help you feel fuller while restricting carbs and calories. In order to lose weight, keeping your calorie intake below your calorie expenditure is key.
Juicing on the Keto Diet
Juicing can help you reduce your calorie intake for fat loss, but it is about as sustainable as a water fast. Although some people juice fast for 30 days, it's really not recommended. You won't get the calories, carbs (notably, fiber), protein and other nutrients you need for good health. In many cases, this can stall weight loss — not only because it can slow your metabolism, but also because you are unlikely to have the energy you need to be active, which is another key part of the weight loss equation.
As for keeping your carb intake low enough to get into ketosis while on a low-carb juice fast — it's possible but challenging. Many juices contain fruits and are too high in carbs to promote ketosis. For example, a recipe of apple, spinach, kale, collard and lemon juice may have as much as 25 grams of carbs per serving.
That's more than the total daily carb limit for keto diets such as Atkins 20. If you were to drink only one juice beverage a day, you could potentially achieve ketosis. But how long would you be able to sustain that and remain in ketosis?
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Low-Carb Juice Fast
Many fresh vegetables can be eaten whole — either raw or cooked — on a ketosis diet without exceeding your daily carb limit. But you have to use a lot more raw fruits and vegetables than you would be able to eat in a sitting to make one glass of juice. Therefore, you get a concentrated amount of carbs in an 8-ounce glass.
For that reason, juicing fruits is out of the question. But even juicing vegetables alone can put you over your carb allowance. For example, a recipe containing celery, parsley, mint, cucumbers and lemons provides about 26 grams of carbohydrates (20 grams net carbs) per serving. Unless you plan to drink only one juice beverage a day, you will exceed the recommended carb intake for ketosis.
That said, there are options — if you can stomach them. Celery only has 3 grams of carbs per cup, and half of that is fiber, according to the USDA. You lose most of the fiber in juicing, so you'd be left with a very low-carb drink. Theoretically, you could juice about 13 cups of raw celery per day and stay right around 20 grams of carbs.
Should You Juice?
There's nothing wrong with juice fasting for a few days. Remember that you'll only stay in ketosis if you choose very low-carb vegetables and don't go overboard on your daily servings. But what will you achieve?
You may drop a few pounds, but a lot of this will be water weight, according to the Mayo Clinic. You'll likely see the number on the scale drop, but it won't be from fat loss. If you're juicing as a way to detoxify your body, don't expect much in the way of results. According to the National Institutes of Health, there's no convincing evidence that juice cleanses actually detoxify your body or improve your health in any way.
If you do a low-carb juice fast longer term, you may see some fat loss, not only because you may be in ketosis, but also simply because your diet will be so low in calories. Thirteen cups of chopped celery have only 184 calories.
But you're going to be damaging your health in other ways, and you're likely not going to feel very well. Celery is a good source of vitamins C and K, folate, potassium and antioxidants, but it's lacking in many other nutrients. Over time, you're likely to suffer deficiencies in a host of nutrients you need for good health.
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Get Your Veggies in Ketosis
If your main goal is to get into keto — and stay healthy in the meantime — a properly designed ketogenic diet is a better bet than juicing. Although maintaining a keto diet is still challenging, it's not nearly as hard as sticking to a low-carb juice fast. The variety of foods you can eat and the increased fat content of a keto diet will help you feel satisfied and get all the nutrients you need, so you can see long-term results.
On a nutritious keto diet, your calories should come from healthy fats, including olives and olive oil, grass-fed butter, cheese (not processed), fish and unprocessed meats, nuts and seeds, avocados and eggs. You can eat plenty of non-starchy vegetables on a keto diet, including spinach, kale, radishes bok choy, broccoli, zucchini and Swiss chard. Unlike juicing, you'll get all the fiber from the whole vegetables, which is not only important for digestive and cardiovascular health, but to fill you up so you can control your calorie intake.
This is a healthy diet you can stick with long term. However, it is still considered a fad diet, because it severely restricts your intake of particular nutrients and foods. According to the Academy of Nutrition and Dietetics, fad diets should be avoided. A better solution for long-term health and weight loss is a well-rounded diet that limits unhealthy carbohydrates from sugar and refined grains, but includes balanced amounts of fruits, vegetables, whole grains and lean protein.
- Colorado State University: "The Truth About the Ketogenic Diet"
- PeerJ: "The Use of Nutritional Supplements to Induce Ketosis and Reduce Symptoms Associated With Keto-Induction: A Narrative Review"
- Academy of Nutrition and Dietetics: "4 Ways Low-Calorie Diets Can Sabotage Your Health"
- Atkins20: "Atkins 20®: A Low Carb Ketogenic Diet"
- USDA: "Basic Report: 11143, Celery, Raw"
- Mayo Clinic: "Getting Past a Weight-Loss Plateau"
- National Institutes of Health: "'Detoxes' and 'Cleanses'"
- Cleveland Clinic: "Celery Juice Is a Trendy Detox Drink, But Does it Actually Have Benefits?"
- Atkins: "List of Low Carb Foods for Atkins 20, Phase 1"
- Mayo Clinic: "Dietary Fiber: Essential for a Healthy Diet"
- Academy of Nutrition and Dietetics: "Staying Away From Fad Diets"