Author: Justin Nault
We’re all familiar with the term “Fruits & Vegetables.” These two food groups have been synonymous since the early days of the original food pyramid. They go together like summer days and cookouts, baseball games and hot dogs, chips and dip, ketchup and fries. Unfortunately, they can also have the same effects on your body as some of the villainous foods I just mentioned. To be fair, I’m going to start by removing vegetables from the equation. Vegetables are glorious superfoods and should be regarded as such. Yet, one of the biggest nutritional myths we’ve ever been fed is this idea that fruits and vegetable are somehow interchangeable. I once had a registered dietician tell me, “If you don’t like vegetables, just eat 7 servings of fruit a day to make sure you’re getting the same benefits.” Some of you might read that statement and not see a problem with it because you’ve heard similar advice your entire life. I’m here to tell you that it could be one of the single most damaging pieces of nutritional advice you could ever give to someone.
*A quick preface for those of you who have been living a Paleo-friendly lifestyle for quite some time. If you have achieved your ideal body weight and physical aesthetics and are free of any serious health problems or gastrointestinal issues, this article probably doesn’t apply to you. I’m writing to those of you who have recently decided to give Paleo the old college try. Just in case you haven’t experienced the miraculous results promised by so many Paleo products and companies. So let’s continue...
If you’re new to Paleo, you’ve probably been told that you want to avoid sugar at all costs. You’ve also seen Paleo food and grocery lists that have “fruits” listed prominently in the “Paleo Approved” column. Without a doubt, fruits have wiggled their way into the “healthy food”category. The question is, do they deserve to be there?
You’ll often hear people citing the benefits of pectin and other soluble fibers when defending fruit intake. These people are correct, but only to a certain extent. When you break down the contents of fruits you’ll find water, dietary fiber, trace amounts of vitamins and minerals, and fructose. For this article, I will be focusing mainly on fructose, which is the huge difference maker when comparing fruits and vegetables. Yes, vegetables also contain fructose, especially sweeter vegetables such as carrots and sweet potatoes. But the amount pales in comparison to that found in the sweet fruits such as apples and bananas. Green leafy vegetables, however, contain very little fructose and an incredible amount of beneficial vitamins and minerals. Heat also causes loss of fructose in the case of cooked vegetables. More often than not, fruits are ingested in their raw form, so you’ll be getting no help from the cooking process.
What Is Fructose?!
Before I get ahead of myself, you may be asking, what exactly is fructose?
Fructose is a simple sugar molecule. It is unique because it is metabolized in the body much differently than other sugars. For example, glucose, another simple sugar, can be shuttled directly to the cells in your body where it can be used for immediate energy. Conversely, glucose can also be routed to skeletal muscle cells and stored as glycogen (the storage form of glucose) for later use. (For more on this, check out my previous article on carbohydrate timing.) There are multiple factors that play a role in how glucose is used in the body such as exercise, blood sugar levels and your current state of health.
Fructose, on the other hand, is processed almost exclusively in the liver. The behavior of your liver is guided by the insulin levels in your body and how sensitive (or resistant) your liver is to that insulin. When fructose levels go up, insulin levels go up, which gives your liver the signal to start absorbing the fructose and converting it. The fructose is converted to glycogen and is then stored directly in the liver. The problem is, the liver can only hold an estimated 60 grams of glycogen. Once the liver can no longer store any more glycogen, it begins converting fructose to fat and pushing it out into the bloodstream. But not just any fat. It converts fructose to small density fatty acids. These particles are also known as Low-density lipoprotein or “LDL.” Also known as, “bad cholesterol.” The kind of cholesterol that is small enough to wiggle its way into the tiny nooks and crannies found in your arteries. Once there, they stick and begin causing inflammation as “foam cells.” This process leads directly to the blockage of blood flow and, ultimately, atherosclerosis.
THE EFFECTS OF FRUCTOSE IN FRUIT:
Now we know a bit more about fructose. So, let’s address the argument that the dietary fiber in fruit somehow curbs the negative effects of fructose on the body. Fructose, in its isolated form, i.e. High-Fructose Corn Syrup, is treated as a toxin in the body. The horribly negative effects of fructose I’ve detailed above are the body’s response to pure fructose. That being said, fructose is never found isolated in nature. When you ingest fruits, you are certainly not ingesting isolated fructose. Fructose is relatively low glycemic on its own. The arguments in favor of fruit state that the soluble fiber that is ingested with the fruit will slow the absorption of the fructose. This could lower the chances of a potential blood sugar spike even further. The only problem with this argument is that the glycemic index is a measure of the immediate consequence of sugars entering the body. There may not be evidence of an immediate effect on blood sugar and insulin levels, but that does not mean that overconsumption of fructose is risk-free. Far from it. A constant surplus of fructose, no matter the source, will eventually cause health problems. Our bodies just aren’t designed to handle a constant fructose load.
Of all carbohydrates, fructose is the most lipogenic. It is the one carbohydrate that we most readily convert to fat in the body. There’s this idea that natural sugars are some sort of health food. But upon further inspection, it’s easy to see that chronic overconsumption of fruit could plausibly lead to a surplus of fructose in the liver. This is especially true if you aren’t eating healthy or following some sort of typical Western diet.Again, I want to be clear that I am talking to those of you who may be overweight or struggling with other health issues. Maybe those struggles have led you to the Paleo diet because all else has failed. If you’re struggling with obesity, odds are, you’re also experiencing some level of insulin resistance. You may already have multiple symptoms of metabolic syndrome. If this is the case, you simply cannot afford added fructose in your diet. If your goal is rapid fat loss, I would highly suggest you limit your fruit intake, considerably. At least, until your biomarkers stabilize. In severe cases, such as gastrointestinal issues like IBS or SIBO, I would experiment with removing fruit altogether. Fructose also feeds bad gut bacteria.
That being said, I have personally seen positive results in body composition, purely for aesthetics, with the removal of fruits from the diet. I have had perfectly healthy clients who simply want to look a little better naked achieve pretty spectacular results with this one small change. It makes sense, from a carbohydrate perspective. For example, 2 to 4 servings of fruit daily could easily add 20-40 grams of sugar and 30-60 net carbs to your daily macros.
In any case, I recommend that everyone increase their intake of green leafy vegetables and experiment with their own fruit consumption to see what works for them. I would also recommend avoiding fruit juices and dried fruit products at all costs. In general, and I’m sure there are exceptions, these products are hiding added sugar. Far beyond what is contained in the fruit itself. Fruit juice is even more of a problem because most of the fiber is removed completely. It’s about as close to isolated fructose as you’re going to get from fruits. To drive the point home, one 12 ounce can of cola contains about 80 calories of fructose. One 12 ounce can of apple juice contains roughly 85 calories from fructose. I don’t know about you, but I would hardly call that a “healthy drink".
If you’re convinced that eating fruit is not a problem for you then, by all means, enjoy! Fruit is delicious! Stick to organic whole fruits. Be vigilant, check those ingredient labels and avoid the processed fruit products. Always be on the lookout for added sugar in the seemingly harmless products, like dried fruit. If you insist on drinking fruit juice, either make it yourself or find a local juice bar and ensure that your juice is made of nothing but whole fruits. Just keep in mind, many of your favorite fruits smoothies probably contain a shockingly high amount of sugar!