Over the past 25 years we have seen a massive upswing in the marketing and growth behind juices and smoothies. As of 2012, Barron's reported that there were over 6,200 juice bars and smoothie shops nationwide. In New York, it's not unusual to see fresh juices and smoothies everywhere — from our local supermarkets to the yoga studio.
Living in Brooklyn, I have seen three new juice and smoothie bars open up within a 10-block radius just within the last two years. To say it's become ubiquitous in most of our lives would be an understatement.
I love juices and smoothies as much as the next person — but when embarking on my sugar detox journey, I wanted to get a better handle as to what ingredients I should be consuming and how. Naturally I thought juices and smoothies would be OK, but here's why they aren't optimal:
1. Juices and smoothies both remove much — if not all — of the produce's fiber.
I know there are some of you right now thinking to yourself, "Wait a minute: smoothies remove fiber too?!?." I know, because I thought this for the longest time as well! Why? Well, because that's what I was told, so I just went with it. When you hear it so many times, it just starts feeling true, but then I started to dig a little bit deeper, which is what I'm about to share with you here.
Fiber is the part of the plant that you cannot digest. Since you can't digest it, it's not classified as a "nutrient," but your body definitely requires fiber to work at its optimum. It's important to note that there are also two types of fiber — soluble and insoluble — and each of these get affected differently when you juice or puree your food.
Soluble fiber, as its name implies, dissolves in water and slows food's digestion and absorption. Insoluble fiber, or the stringy parts of the plant that aren't dissolved in water, help push food through the gut. When you juice fruits and veggies, all of the insoluble and soluble fiber is removed. When you blend a smoothie, the "shearing action of the blender blades completely destroys the insoluble fiber of the fruit," according to Dr. Robert Lustig in his 2013 book, Fat Chance. Yes, the soluble fiber is there but the intricate latticework of the insoluble fiber is blown to smithereens. If you're replacing your meals with juices and smoothies, you're likely not getting enough fiber in your diet.
2. Juices and smoothies give your body a sugar spike.
The recent academic assertion by Lustig above has been backed by much research over the past forty years, particularly from scientists who study how quickly carbohydrates (sugars) enter the body for those who suffer from hyperglycemia. If you are drinking juices and smoothies, particularly ones with fruits, you are likely giving your body a sugar spike.
A great 1977 study by Haber, et al. showcases this effect. Even though the study was small, the results were statistically significant and conclusive. The study showed that the blood glucose and insulin response to whole apples was increased by blending the apples to a puree (smoothie) and by extracting the juice (juicing). When the rate of ingestion for the different foods were equalized, the plasma-glucose was shown to rise to similar levels after the meals. However, there was a "striking rebound fall after juice and to a lesser extent after the puree," which was not seen after the consumption of the whole apples. Serum-insulin then rose to higher levels for both juice and puree, so the study concluded that yes, when making juices or smoothies, you are definitely disturbing your glucose balance largely due to fiber loss.
It also should be pointed out that juices and smoothies in general usually contain way more than the 2 servings of fruit/day. The NY Daily News recently revealed the amount of sugar in some popular juice cleanses. Organic Avenue's Love Easy juice and diet cleanse gives you 75 grams of sugar per day — 50 grams over the suggested daily limit for women. BluePrint's six-juice-per-day cleanses range from 146 to 191 grams of sugar, and Juice Press' six-juice daily "cleanse" has 92 grams. Considering what sugar can do to the body, we might want to steer clear of those sugar bombs.
3. Juices and smoothies aren't as satiating.
The removal and disruption of the fiber matrix in juices and smoothies, respectively, not only can affect your sugar levels, but it is also shown to be less satiating. This means we tend to consume more, if not right away then likely later in the day. A 1981 study by Bolton et al. in the American Journal of Clinical Nutrition, showed that physically blending food results in faster ingestion and absorption, but resulted also in decreased satisfaction so people drinking their meals, whether in juice or smoothie form, tended to get hungry again before their next meal.
This isn't a big shocker to me, as I always found myself wanting to consume more juice and more smoothies or more solid foods, even after I had one. Remember BluePrint cleanse? I recall drinking one of the $9 (yes $9!) juices, because I liked the taste, and someone came up to me and asked, "Oh, are you on the BluePrint cleanse?" I hadn't a clue as to what she was talking about. I guess I was out of the loop on the whole juice cleansing thing, but I said, "No," as I was just about to go grab some real lunch. Whoops!
4. They're expensive.
That brings me to my fourth point: Juices and smoothies are expensive! Damn expensive! Granted, if this is the only way that you and your children insist on getting your daily intake of fruits and veggies, then it's probably better than nothing at all, but it also means that you're likely spiking blood sugar, eating more and breaking the bank. The major cleanses cost around $58-$65 per day, which is really tough to justify, particularly after finding that with some advanced planning, I could easily make 10 delicious, nutritious, locally-sourced meals for less than $50.
5. You waste the really good stuff.
Food is a terrible thing to waste. NPR reports that in 2010, 31% of the total food supply in the US —133 billion pounds of food — was wasted. That's $161.6 billion out the door and into the landfills! With smoothies, at least we're consuming the whole fruit or veggie. But with juices, we end up throwing out (or composting) a lot of waste. I couldn't find reliable sources as to how much we waste juicing (and of course that depends on what we're juicing), but I did find that the Florida orange industry harvests 90 percent of all oranges solely for their juice, which then results in 3.5 billion pounds of dry waste, mostly peel and pulp.
There are, of course, benefits that people experience from drinking juices and smoothies as well—and in many cases, it might be a person's first move in making dietary changes in his or her life (drinking veggies somehow seems far more appealing than eating them sometimes!), but we should be fully aware that our body handles liquified foods very differently from whole, solid foods.
Additionally, it's important to remember that the digestion process doesn't start in our stomachs — it starts in our mouths. A recent study in the Journal of Experimental Biology and Medicine shows that appetite is reduced by nerve feedback from the teeth to the brain when you chew. So if reducing our sugar loads and weight loss in the long run are our goals, then we may just want to think twice about slurping down our meals.