Nutrition in the News


Scarlett Crews, RDN, LMNT

Sure, Gwenyth Paltrow, Salma Hayek and even Beyonce all credit their slim figures to days of “detoxing,” meaning they only drank raw, pressed vegetables and fruits in juices.  And since celebrities do it, it must be healthy, right?  Not so much.  While juice diets are wildly popular, we dietitians have to take a step back and mark potential warnings that can come from “detoxing” your diet for days.  Why do I keep throwing quotes around the word “detox”? Because it’s a fad word that has lost its true meaning.  You were gifted two kidneys and one liver that detox your body on a daily basis.  While I am always a fan of getting in more fruits and vegetables, let me explain why juice-cleansing is a bad idea.

How your body is affected…

With the first sip of your new juice, easily-digested carbohydrates dump into your stomach and are immediately broken down into glucose.  From here, your blood glucose sky-rockets, leaving your pancreas to spit out insulin that immediately goes to work soaking up all the sugar that was just dumped into your stomach.  Because there is very little protein and zero fat in these juices, this spike is short-lived and causes a dramatic drop in blood sugar, leaving you weak, shaky and hungry.  This leads me to my next argument:  the imbalance of hormones!

Spike in Insulin

Your body’s hunger hormone, Ghrelin, activates when your blood sugar is low and tells you to eat.  The problem lies when you drink a few hundred calories of pure sugar, which dumps into your gut and causes your insulin to spike.  From here, the fruit sugar (now glucose) is quickly absorbed into your cells, your blood sugar drops dramatically and your ghrelin hormone reactivates.  Ghrelin and your full-feeling hormone, Leptin, cannot keep up with your roller coaster blood glucose, most of the time ending in a frequent state of hunger.  Your small intestine doesn’t really get to participate in the fun either, since the sugar is so easily broken down, which leaves the villi (tiny finger-like structures that help move along food) to atrophy and cause diarrhea.  Juicing produce strips away the fiber, leaving you with a low fiber, high sugar and high fluid food that will keep you close to a bathroom.

Protein and fat deprivation

Typically, a juice cleanse consists of less than 1,000 calories per day, zero fat and minimal protein.  This severe deprivation causes your body to rely on its glycogen stores, which deplete very quickly.  This leads your body to break down energy stored in fat cells and muscle.  With each day on the juice cleanse, more muscle mass is lost (which is why the scale is going down), your brain is now starved for fatty acids and amino acids, which can cause brain fog, cognitive impairment and depression.  The proteins that are released from your shrinking muscles excrete ammonia and uric acid, which are toxic chemicals that force your kidneys to detox your “detox diet”.

After days of living on barely any calories, you now get to eat real food.  The problem is that you have allowed your body to go through a roller coaster diet and have decreased your metabolism and muscle mass in the process.  Still dying to juice?  It’s a great thing when it’s paired with a well-balanced diet of fats, carbs and protein.  The best way to detox is by eating a sensible, whole-food diet.  Leave the detoxing to your kidneys and liver.

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