Are You A Smoothie Criminal?


Several factors determine whether your smoothies are satisfying and healthy.

Is Blended Food Less Nutritious?


Some nutritionists say drinking smoothies are an efficient way to get nourishment. Balkers deride smoothies as conduits for sugar with useless pulverized fiber. Is it possible to receive essential vitamins and fiber from blended beverages? Are your efforts to do so a crime against nutrition?

Love or hate smoothies? Both sides of the nutrition debate appear valid on the surface. Repeat whichever argument you favor among your circle of influence to create credible audience support. But what does the science teach us? Robin Spiller, director of biomedical research at the Nottingham Digestive Diseases Centre in the U.K. has answers. What matters is the composition of your smoothie and the rate at which you consume it.

Digestive Conveyor Belt

The brain must receive a series of signals through the vagus nerve. This connects gut and brainstem as well as digestive hormones secreted by the gastrointestinal tract to signal when you are full. Have you heard that it takes 20 minutes for your stomach to recognize you have begun eating?

Wait a minute. Are we to understand that everyone—young or old, tall or short, morbidly obese or peek of physical fitness—has the exact same internal clock for satiation?

Well, it seems the timing quote is inaccurate. Actually, time varies for each individual between 5–20 minutes, according to Zane Andrews, associate professor of physiology and a neuroscientist at Monash University.

Since most people do not know whether their satiation trigger is closer to 5 or 20 minutes, the longer interval is a safe guideline to follow. Slow down so your stomach is not “surprised” to discover when it reaches uncomfortable capacity.

Duodenal, jejunal, and ileal receptors gauge the nutritional value of what is coming from the stomach.

You have likely said something like, “That sounds so good, you’re making me hungry.” Each part of our digestive system receives advance sensory clues to accept a meal. We cannot swallow without saliva, so hearing, sight, smell and taste receptors stimulate salivary glands, which lubricate your esophagus.

Our stomachs must excrete gastric juices to breakdown food. Our senses as well as regular meal-time intervals trigger gastric secretion, associated with hunger. Through a process called gastric sieving, our stomach separates solid mass from water. Liquid drains first, so gastric juices can better breakdown solids.

Duodenal, jejunal, and ileal receptors gauge the nutritional value of what is coming from the stomach and control the rate of transport. Water goes through express checkout. High-nutrient stomach contents go though a turnstile at a rate of 1 calorie per minute to keep gallbladder and small intestines from being overwhelmed. The small intestines shouts out to the large intestines, “move things along” to make room for what is coming down the “conveyor belt.”

So it would seem that your smoothie, being liquified, goes straight to the express checkout, right? Not so fast. The homogenous mass does not promote gastric sieving nor does it need for the stomach to break down solids. But remember the duodenum regulates calorie consumption. If filled with blended nutrients, the smoothie remains in your stomach longer than something like a cup of water or apple juice.

Blended vs. Solid Food

To test absorption of solid versus blended meals, Nottingham researchers compared a combination of meat, vegetable and water to a blend of the same ingredients in soup form. (This differs from light-viscosity soup with separated solids.) High-speed imaging equipment traced the rate of absorption throughout the digestive tract. The blended soup kept participants satiated for about an hour longer than the whole-food meal!

Login Register

Include Meaningful Comment