Juicing is Dangerous.
I get asked all the time about juicing or “smoothies”. Most of the smoothies are described as rich combinations of green vegetables, or yogurt, or fruit. Then, I had someone describe to me how their blood sugar went up almost to 1,000 with a seemingly innocuous concoction. What’s going on that can make that happen?
This column has reviewed the science of changing an apple to apple sauce, then juice before. Barbara Rolls and her team at Penn State observed 58 random volunteer adults for a meal once a week over 5 weeks. Each volunteer was provided a precise “preload” of calories weighing exactly 226 grams with 125 calories in it; aka, one really nice apple. After 15 minutes, they eat whatever they wanted for their meal.
This is what they found. Eating a whole, solid apple resulted in a 15% reduction of calorie intake. That is a 62-calorie reduction for the entire meal. That would be interesting enough by itself. You can lose weight by having an apple 15 minutes before a meal! (62 calories a day is 1800 calories a month or 6 pounds a year.)
But wait, it gets better. Here is the heart of the juicing question. When they changed the apple into applesauce with the same weight, calories, rate of ingestion, timing, resulted in eating 91 calories less overall. Then change the calories into juice. It became 150 calories less.. Applesauce reduced total meal calorie consumption a tiny bit, compared to juice which had virtually no reduction in calories.
The final sword in the experiment was to add fiber added back into the apple juice. Now it becomes a drinkable product, aka juicing. You erase the positive effect of eating a whole apple before a meal. The drinkers did compensate for their calories in the meal, but they did not reduce their total overall calories like eating a whole apple did. It’s interesting that juice, with or without fiber had the same effect. Being liquid just doesn’t register in your brain, no matter the fiber content. Did you get that, juicing erases the message to your brain about content of food.
Our brains and physiology are quite complex. Part of a meal is the actual process of “eating” it. Chewing our food makes a difference in how much food we eat. Stretching it out over time makes a difference. The waiting of 15 minutes before the meal may have been part of the impact. We call that part the cephalic phase during which your body starts to get ready to digest and process food. Managing your cephalic phase sounds like heavy science. Or maybe it’s just plain heavy weight gain.
Here’s my take on it. Eating the whole fruit delivers fiber with the sugar and slows the process of absorbing the sugar dramatically. Mechanically grinding up an apple, or any vegetable, is far more efficient than chewing in terms of mechanically disrupting the cell wall and releasing the sugars inside. When you drink it, you get a burst of glucose delivery to your gut. This results in a burst of insulin release. This results in a burst of LDL production to ship fat to your fat cells instead of energy to your brain and muscles. You thought you ate 800 calories for your meal but your body is saving some of it to fat, because of the insulin burst. Hence, you eat more.
Moral of the story: juicing changing the way you get nutrients: the speed, the mechanics of chewing, the rate of glucose rise all are disrupted. You gain weight.
Now, if you are averse to vegetables and you can’t get them any other way……and aren’t overweight. I’ll relent. If your smoothie is just kale and asparagus and yogurt, I’ll concede. But throw in an apple or a banana, and my skepticism goes up. The heart of the matter is that today’s apple is really much more endowed with sugar than nature’s original apple. Malus Sikimensis, the Himalayan apple is the worlds original, and has a very bitter/sour flavor, sort of like a crab apple. We have changed it into a Golden Delicious, with 1% of it’s original phytonutrients and 10 times its sugar. Hmmm.
www.What will work for me. Eat the whole food. Chew. Sit. Wait. Talk. Enjoy. Visit. The calories you drink are the calories you store. Repeat after me. The calories you drink are the calories you store. Plain and simple.
- Juicing is really healthy for me? Answer: Please reread this column
- I hate vegetables. If I juice them, I can get some down. Is that ok? Answer: if you keep the high glycemic fruits out of it, you are getting some fiber this way, but be careful if you are trying to lose weight.
- The calories I drink are………… Answer: The calories I store. (smoothies)
- The calories I drink are ……………. Answer: The calories I store (beer).
- The hormonal effect of food is more important for weight control than the quality of the food. T or F Answer: True. That’s the secret behind this message. Smoothies make glucose be delivered too fast, turning on insulin. Insulin is your storage hormone. The exact same food, delivered slowly and with fiber built in makes for a different metabolic product.