I have recently come upon a few clients and friends who have mentioned they love to incorporate smoothies into their diet, so that encouraged me to talk about this topic to clarify a few misconceptions around the premise that smoothies are healthy. Smoothies that consist of only fruits are far from healthy. Those big smoothies that have 3+ fruits are probably helping you gain weight. “But fruits are supposed to be healthy and good for you” is probably what you are thinking right now. You are right, they are but in moderation. The problem with smoothies is that we usually use more fruit than if we were to eat the fruit on its own. It is the same thing with that orange juice we love so much. Ask yourself this, if you had to eat the fruit itself, would you eat 3-4 oranges in one sit? Probably not. However, that is probably the number of oranges you would use to make your juice. The problem is not the fruit itself, but the distortion of the quantity that happens when we blend them.
Let’s get into why it is so bad for you. I need to get into some boring nutrition technicalities first so you can really understand why fructose is so bad for you, so bear with me, please. We all know that fructose is the sugar found in fruits. Fructose is in the family of carbohydrates, and it is a monosaccharide which means that it consists of only one sugar. Another very important monosaccharide that is vital for our metabolism is glucose. From that molecule of sugar is where we make most of our energy. From the glucose we ingest (let’s say 50gr), our cells take approximately 80% of it so they can make energy with it. The other 20% is sent to the liver so it can be stored as glycogen (a form of stored energy). Once this whole mechanism starts and insulin is released to regulate the sugar, the pancreas then releases a hormone called leptin. This hormone is in charge of telling our bodies when we are full and need to stop eating. Here is the big twist, though: fructose does not follow this same path/process. Cells are not capable of using fructose as a source of energy, so 100% of it goes straight to the liver. The liver can only metabolize a certain amount of glucose and fructose, so when it hits its limit (which is not very high), the rest of the fructose is turned into fat. Leptin doesn’t detect fructose either, so that is why after having some of those smoothies or juices, we feel hungry for the rest of the day. Our brain never gets the signal saying that we’ve had enough food.
On top of fat storage, high fructose levels also pose serious threats to cardiovascular health. Without getting into much detail, let’s say that the way in which fructose arrives in the liver is not friendly. Glucose usually uses a protein and a receptor to get into the liver, however, fructose just goes in all at once without previous warning. The liver then has so much fructose that it requires tons of energy to metabolize it. This makes the body activate other mechanisms to help with that “oversaturation”. One of those mechanisms is the release of uric acid, which causes inflammation in the body. High levels of uric acid also mean low levels of nitric oxide, which is something we do not want because nitric oxide helps us with circulation. So as a result of high fructose levels, people end up with artery issues such as hypertension. Now, am I saying that all the bad effects of fructose come only from fruits? Absolutely not. That is also a huge misconception. Most people think that fructose can only be found in fruits. That is not correct. Remember how at the beginning of the article I talked about fructose being a monosaccharide? Well, there are other types of sugars called disaccharides. These ones have 2 molecules of sugar in them. Common table sugar (the one we find in cakes, cookies, ketchup, ice cream, etc.) is called sucrose, and it is a disaccharide that is made of 2 monosaccharides: glucose and fructose. So if you put 2 spoons of sugar in your coffee every morning, just keep in mind that half of it will go straight to your liver, overwork it, and stimulate fat production and storage. And so the huge myth is that eating foods high on fat is what is making you overweight, hypertense, and prone to heart disease when the reality is that most of those conditions come from and start with high levels of fructose.
So let’s just wrap this up and get to the point. I am not saying that you should stop eating fruits completely. Not at all, please DO INCLUDE them in your diet. They are rich in vitamins and minerals that our bodies need. I’m just recommending to be careful about how much of them you put in your smoothie, or to eat the fruit itself instead. Always in moderation. I personally like to include veggies in my smoothies, because at the end of the day who doesn’t like smoothies? They’re yummy and quick to make. I usually use ½ cup of blueberries, strawberries, spinach, and cucumbers. Might sound weird, but I find it very tasty and most importantly, it’s healthy! So from now on just try to be mindful of smoothies, juices, high-fructose corn syrup, and table sugar.