Fructose: It's just sugar, right?

Bug Juice is natural??

I recall a television commercial a few years ago that was promoting high fructose corn syrup, and the internet being what it is, I was able to find it. It was paid for by the Corn Refiners Association. The spot centered on a mom to mom conversation about high fructose corn syrup and a gallon jug of a red beverage that looked eerily similar to the “bug juice” I had at summer camp.

It begins with one mom accusing the other of not caring what she feeds her kids because she’s giving them high fructose corn syrup - “You know what they say about high fructose corn syrup...” The bug juice pouring mom comes back with, “It’s made from corn, it’s natural, and, like sugar, it’s fine in moderation.” You are then encouraged to “get the facts” from a website created by the Corn Refiners. The commercial did not have a very long life - sometimes consumers are smart.

But, it’s made from corn…

If you are not yet in tune with just how much sugar you are consuming in a day or how toxic that sugar is, you are not alone. According to the CDC, the daily intake for sugar in 2017-2018, was 17 teaspoons for children and young adults, 19 teaspoons for adult men, and 15 teaspoons for adult women.(1)  There are about 4 grams of sugar in a teaspoon. Most of the sugars that we consume in the US come from sweetened beverages, desserts, and sweet snacks - all of which are highly processed.

Sugar is indeed one of the worst toxins in our diet, but I want to dig into a specific type of sugar that has its unique toxicities. You guessed it - fructose. 

But wait, isn’t that the natural sugar found in fruit? Yes, it is naturally found in fruit of all kinds, honey, agave, and molasses. You probably recognize some of the “natural” sugars in this list that you have been using to replace your table sugar (sucrose). Table sugar is actually half fructose and half glucose - so is honey. Fructose is commonly sourced from corn, sugar beets, and sugar cane. Sounds “natural”, doesn’t it?

So what’s the problem with fructose?

Fructose is metabolized by your body differently than glucose. Any time we consume carbohydrates, our body breaks them down into their simplest form (a monosaccharide) so that they can be most easily absorbed into the bloodstream. Glucose and fructose are both monosaccharides. Glucose travels around in the blood and gets picked up by cells for immediate use or for storage as glycogen and fat. Every cell in the body can use glucose. This is the “sugar” that diabetics measure in their blood. Over 80% of glucose is metabolized by cells other than the liver. The other 20% is converted to glycogen by the liver for short term storage.

Fructose on the other hand, can only be metabolized by the liver and it does not travel around in the blood to supply energy for cells. The fructose that is metabolized in the liver is first stored as glycogen, but when the glycogen stores are full, the fructose then gets metabolized to liver fat. Yes, fructose directly makes your liver fat. The problem with this fatty liver is that it plays a critical role in the development of insulin resistance. Since insulin resistance is the core problem in diabetes and probably obesity, consuming fructose is much more deadly than consuming the same amount of glucose. Glucose causes almost no new fat generation, but the same number of calories consumed as fructose can cause your body to create double the amount of new fat. In one study, participants consumed 25% of their calories as either fructose or glucose. At the end of 8 weeks, the glucose group had gained 3 pounds but the fructose group had gained 17 pounds and had also developed fatty liver disease.

The small amount of fructose that we would consume by eating raw fruit (roughly 15-20 grams per day or 4-5 teaspoons) is not harmful. Over the last one hundred years or so, refining sugar has become easier and cheaper especially with the development of high fructose corn syrup (HFCS) in the 1960’s. HFCS is much cheaper than sucrose and food manufacturers rushed to replace the sucrose in their products with HFCS. By 1994, the average person was consuming 55 grams of fructose per day, and more recently, it has gone up to 86 grams per day. Countries that consume large amounts of fructose have a much higher rate of diabetes and obesity.

The body cannot store extra fructose. Once the glycogen stores are full, fructose gets turned into liver fat and there is not an easy way to reverse this process. Long term, ingestion of fructose causes fatty liver and insulin resistance.

Fructose also does not tell the body you are full. There are natural satiety signals that the body receives when it has had enough food. Fructose however does not stimulate those pathways. It will never make you feel full. Instead, it stimulates the hormones that make you hungry so you end up eating more of the foods that contain fructose.

Fructose is not just another name for sugar

There is nothing healthy about consuming fructose at the levels we do today. Remember, fructose exists naturally in fruits at very low levels. In those small amounts, it is not deadly. 

However, all you have to do to make it unhealthy is to create a cheap sweetener called high fructose corn syrup and put it in almost every processed food, and then you have yourself double epidemics of diabetes and obesity. 

Fructose is not metabolized like other sugars. It can only be metabolized by the liver and leads to fatty liver followed by insulin resistance. Insulin resistance is the core problem in diabetes and obesity. 

Calorie for calorie, fructose will cause your body to make more fat than glucose will. Fructose also does not stimulate the hormones that make you feel full but instead stimulates the hormones that make you hungry causing you to eat more. 

So, the bug juice mom was wrong. Fructose is not at all like other sugars and we are not consuming it in natural amounts. Reason #1046 to avoid processed foods!