When I was in college, I decided that doing a juice fast was the perfect way to get my health back in order. Six hours and two glasses of juice later, I gave up; I was hungry, weak, and supremely grumpy. If this was how I felt after just a few hours, how on earth could I last an entire week?
I may lack the willpower to go on a juice fast, a regimen where you subsist only on fruit and vegetable juices for as many as several weeks, but plenty of other health-conscious people swear by them. And yet, despite claims that juice fasts detox the body, help you lose weight, and even cure serious illnesses, most mainstream medical professionals are speaking out against the practice.
So who should you believe? Let’s take a closer look at the claims, and the science, behind juice fasts.
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Claim: You’ll Lose Weight.
You bet you’ll lose weight, just as you would with any other diet plan that restricts calories. You could, for instance, eat 800 calories worth of chocolate chip cookies, and only chocolate chip cookies, every single day and see the pounds melt off. Juice may have more vitamins and minerals than cookies do, but that doesn’t necessarily mean the weight loss you experience during a fast is any healthier. The weight you’ll loose will most likely be water weight, and you’ll probably gain it all back — and then some, perhaps — as soon as your diet returns to normal.
Claim: Fruits and Vegetables are Healthier in Juice Form.
Juice doesn’t have the same amount of dietary fiber — if it has any at all– as whole fruits and vegetables do. Juice cleanse proponents claim that the lack of fiber gives your digestion system a breather; however, fiber is an essential nutrient for digestion.
Claim: Your Chronic Illnesses Will Disappear.
Juice fasts do provide you with more vitamins and minerals than most of us would get otherwise. These vitamins and minerals do make us healthier, but two things that juice fasting omits, a sustainable number of calories and protein, can actually make us sicker.
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Claim: Your Body Will Detox.
Our bodies are exposed to scant amounts of harmful chemicals every day — there’s no denying that. However, there is no scientific evidence that a diet consisting solely of fruit and vegetable juices will actually deter these toxins. All of the supposed benefits of detoxes are functions that actually performed naturally by our kidneys, livers and intestines — organs that could actually get more damage from a juice fast.
Claim: You’ll Have More Energy.
In an article on juicing for the New York Times, Dr. David Colbert told the author that the euphoria some juice fasters experience is a bodily process called ketosis. “That giddy feeling you get is what diabetics get when your body runs out of sugar and starts using other products for energy… I had a model come in recently, clutching the furniture, explaining to me that she’d been juicing for a week. Your sugar metabolism is completely out of whack.”