Stop fearing fructose!
Nearly every day someone asks me if they should be cutting fruit out from their diet because they have heard that fructose is addictive, fattening, poisonous or- my favorite argument- causes fatty liver. These clients refuse to eat bananas, drink orange juice, or even use honey because they contain fructose in large amounts.
We all know that these days sugar is the new fat as the evil of all evils in our diets. After all, we need something to blame for all our diet ills.
But does fructose really deserve it’s bad rap?
You be the judge.
Before we begin, let me clarify that this is a post on fructose occurring in nature. I am not referring to high fructose corn syrup created in a lab. Those detractors say “fructose is fructose” and I completely disagree.
Read on to find out why…
As is the case with many of the current nutritional studies, many of the reasons fructose is so maligned hold no significance to humans.
“Why?” you ask.
First, the vast majority of these studies are conducted on mice and rats. Rodents’ bodies are vastly different to humans in how they metabolize sugar insomuch as they convert sugar to fat infinitely easier than humans.
Second, studies use unrealistically high doses of isolated fructose, so much so, in fact, that they closely resemble toxicological studies rather than nutritional. It is virtually impossible for a human to attain the levels of fructose (especially in isolated form) in the context of a normal diet, especially if the fructose is coming from whole unprocessed food sources.
Side note: The context of this article is fructose as it pertains to a healthy, well balanced, largely unprocessed diet of real foods including fruits and vegetables. It IS possible for fructose to become a problem if you are eating a processed diet including large amounts of sugary drinks, candy and other SAD (Standard American Diet) staples. It is not, however, SOLELY fructose that is problematic in this case though.
Relevant human studies show absolutely NO negative effects to the human body when eating up to 100g of fructose per day. Let’s give you a little perspective here. You would need to consume 5 whole cantaloupe or 15 bananas to hit 100g!
In humans, fructose is simply NOT the poison it’s painted to be.
Need more detail? Let’s break it down myth by myth.
Fiction: Fructose stores immediately as fat.
Fact: Unlike rats and mice, the human body does not readily convert fructose to fat. Isotopic tracer studies show:
The vast majority of the fructose we eat breaks down to about 50% glucose and 30% lactate. (a lactic acid salt)
Studies show that less than 1% of fructose actually gets converted to fat.
Fiction: Fructose is addictive because it doesn’t trigger our insulin and leptin, (hormones responsible for sending signals to the brain that we are full). Eating fructose will lead to overeating.
Fact: Many controlled human studies show that isolated fructose is no less satisfying than other forms of sugar. However, this fact is irrelevant if eating a real foods, unprocessed diet because in a whole food, as in nature, fructose is never isolated. READ: Fructose never occurs on its own!! Glucose always accompanies fructose and glucose does stimulate the satiety hormones leptin and insulin. Raw honey is, for example, 50% glucose and 50% fructose. The same goes for orange juice!
Fiction: In the Paleolithic (pre-agricultural) era, fruit didn’t contain as much fructose. YES, I am picking on you Paleo people!! The fruits we eat today are ‘bred’ to be sweeter.
Fact: There is no evidence that shows that wild fruit varieties contain lower amounts of fructose than cultivated fruit. (Though Paleo propaganda would say otherwise.) In fact, in some studies, wild fruit actually contained 20-40% versus 10-30 % of total sugar in comparison with cultivated fruits.
Fiction: Humans have not evolved to eat fructose.
Fact: Humans have been eating fruit (which contained fructose) and even harvesting honey (dating back to 15,000 years ago) throughout our evolution, going back as far as 60 million years ago with our early primate ancestors. Even today, there are hunter-gatherer populations who exist largely on fruit. Within these populations there are low to no incidences or cardiovascular disease, diabetes, or strokes. There are also no incidences of obesity.
Side note: There are parts of the population with genetic variances of the ALDOB gene that do not tolerate fructose and, therefore have a hard time tolerating sugar. This gene is responsible for providing instructions for making the aldolase B enzyme. This enzyme is one of a group of three aldolase enzymes that are responsible for breaking down certain molecules in cells throughout the body. Four identical aldolase B enzymes need to be bound) to each other in a four-enzyme unit called a tetramer to work.
Aldolase B is found primarily in the liver, but it is also present at lower levels in kidney and intestinal cells. Aldolase B is involved in the breakdown (metabolism) of the simple sugar fructose, which is found mostly in fruits and is used in the body for energy. Aldolase B is responsible for the second step in the metabolism of fructose, which breaks down the molecule fructose-1-phosphate into glyceraldehyde and dihydroxyacetone phosphate. To a lesser degree, aldolase B is also involved in the breakdown of the simple sugar glucose.
There are also genes such as Gly16, ADBR2, FTO, and PPARG (to name a few) that speak to your ability to metabolize sugar but even these are genetic variances that can be silenced if they exist and are only variances in very small parts of the population!
Fiction: Fructose leads to insulin resistance.
Fact: Fructose, in the presence of glucose, has been shown to be beneficial in the management of insulin resistance and Type 2 Diabetes. Fructose has been shown, over and over, to lower resting blood glucose levels and improve insulin sensitivity and hemoglobin A1c.
Here’s the rub:
Anti-fructose propaganda as anti-sugar propaganda may be pervasive, but the “science” it uses is misleading, at best. It’s imperative we educate ourselves and continue to question the real evidence behind the sound bytes and silliness. Only then can we make informed choices about the food we eat.
Unless you have a reason to fear you don’t metabolize fructose (and we will be discussing that in the near future) stop fearing fructose. Nature is infinitely intelligent and orderly and where would we be without pineapples, mangos, berries, cherries, peaches, and…… oh my…. Time to go make a smoothie!!
Wishing you health, wellness and beauty,
Do you want to drop the pounds and think fruit might be your enemy? Project Transform Me Weight Loss Edition can tell you about your genes, how they are expressed and the best way to eat, lifestyle changes to make, and supplements to take (and there aren’t as many as you may think!) to tip the scales in your favor, slim down and get into the best shape of your life!!