This page is here to help you understand why fructose can be especially harmful if you have diabetes or struggle with obesity. While dietary glucose is already problematic, fructose may pose even higher risks. It is necessary to learn which foods are high in fructose and make a serious effort to avoid them.
For people with diabetes or excess weight, avoiding high-fructose foods should be a top priority. It requires consistent, even uncompromising discipline. In this sense, take an example from Muslims and Jews, who fanatically avoid pork under the threat of divine punishment. The low-carb religion views disability and early death as divine punishment for eating forbidden foods that are high in fructose and other carbohydrates.
Before we dive into how your body processes fructose, explore my article on glucose. It contains helpful foundational information.
The Fructose Factor in Diabetes and Obesity
Fructose is harmful for people with diabetes because it promotes weight gain. Also, it can trigger gout. Most of the fructose you eat gets converted into fat. A large portion of that fat builds up in the liver, while the rest tends to settle around your waist, belly, and hips.
Today, a large number of people suffer from a condition called non-alcoholic fatty liver disease (NAFLD), also known as non-alcoholic steatohepatitis. In rare instances, it can progress to fatal liver cirrhosis. But even if it doesn’t, having fatty liver disease still means a shorter life expectancy. The primary driver behind this metabolic disorder is the consumption of excess fructose, which the body does not need.
How Fructose Reduces Insulin Sensitivity
When fat builds up in the body, it reduces insulin sensitivity. In other words, the body becomes more resistant to insulin. For people with diabetes, this is a serious problem because it forces them to increase their insulin doses. Unfortunately, insulin can promote further fat accumulation, creating a vicious cycle. More fat leads to more insulin resistance, higher insulin doses, etc.
This downward spiral often results in severe complications and early death. And it begins with the regular consumption of harmful, carbohydrate-rich foods overloaded with fructose. Many people turn to these foods out of habit, lack of information, or simply because they are an easy and cheap way to cope with stress or boredom. The comforting carbohydrates may offer quick relief, but they do so at the expense of your long-term health and well-being.
Foods High in Fructose
Foods high in fructose to be cautious of:
- Most fruits and berries (except for avocados and olives)
- Sweet vegetables like pumpkin, carrots, and beets
- Juices squeezed from fruits or sweet vegetables
- Honey
- Table sugar, including brown sugar
- Carbonated drinks (except those with zero calories)
- “Diabetic-friendly” treats — cookies and snacks that may mislead you with a friendly label
When treating hypoglycemia in a diabetic patient, it is preferable to avoid the products listed above. Instead, pure glucose should be used, as it is more effective than glucose mixed with fructose. If pure glucose tablets or a glucose solution are not available, the patient should eat a small portion of flour-based foods. Options include porridge or cooked potatoes. They can provide a reliable source of glucose.
Here are the key takeaways about fructose that every person with diabetes should remember. What follows is a deeper look into fructose metabolism in the human body. You are welcome to skip this part.
Fructose Metabolism: What Happens After You Eat It
In the article about glucose, we explained how all chronic complications of diabetes develop. Their common cause is that glucose sticks to proteins and damages them. These damaged proteins are called advanced glycation end products, or AGEs. As they build up in the body, they interfere with the normal function of the kidneys, eyes, nerves, and many other organs. Over time, it leads to serious complications, disability, and death. Fructose is even more dangerous in this regard. It binds to proteins and forms AGEs more readily than glucose.
The fructose you eat is digested in your gastrointestinal tract and enters your bloodstream. Every few minutes, your blood, containing hundreds of different substances dissolved, passes through the liver. The liver commonly allows glucose to pass through. Sometimes, it even adds glucose to your blood by breaking down the glycogen stores. However, with fructose, the process is different. The liver works hard to remove it from the blood and process it internally.
The body knows that fructose should not circulate in the blood for long. If it stays in the blood too long, it can enter various tissues and cause damage by forming advanced glycation end products. To prevent it, the liver works hard to remove fructose from the bloodstream. It locks it inside and then neutralizes it.
How Eating Fructose Contributes to Gout Risk
When liver cells detect fructose, they perform a process called phosphorylation on its molecules. Once fructose molecules are phosphorylated, they can no longer leave the liver and return to the bloodstream. Whenever the liver phosphorylates many fructose molecules at once, a byproduct appears, called adenosine monophosphate. It can contribute to the development of gout.
Of course, not everyone who eats a lot of fructose will develop gout. Its appearance depends not only on diet but also on genetic predisposition. Regardless, there’s no reason to take unnecessary risks. Fructose is only beneficial for severely malnourished or starving people. In all other cases, its metabolic toxicity far outweighs any potential benefit.
Recently, the link between dietary fructose and gout has been officially recognized by organized medicine.
Ingestion of fructose-sweetened foods and beverages has also been implicated with an increased risk of hyperuricemia and gout. Fructose is the only sugar known to elevate serum uric acid levels.
– Goodman and Fuller’s Pathology, 2020.
Science™ believers continue to hope that allopurinol or other pills will save them from gout. Conspiracy theorists and flat-earthers who deny Science™ emphasize a low-carb diet with strict avoidance of foods high in fructose.
Why the Body Turns Fructose into Fat
Fructose processing in the liver does not end with phosphorylation. That is just an intermediate step. The problem is similar to what happens with glucose. There is usually too much of this substance available, so it is impossible to burn it quickly. Storing fructose is also a challenge because it easily damages proteins. And the body’s storage capacity isn’t unlimited.
In our current living conditions, it would be ideal if the body could readily excrete excess fructose in the urine. But humans are not built that way. Maybe there were people in the past who had this ability. However, they likely failed to survive one of the many long periods of starvation and left no descendants. So, like glucose, the body is forced to handle excess fructose by converting it into fat and storing that fat.
The conversion of fructose into fat occurs in the liver. Most of this fat stays in the liver, fueling the development of fatty liver disease, as discussed above. The more fat builds up in the liver and elsewhere in the body, the more insulin resistance increases. The combination of type 1 diabetes and obesity is called diabesity. It is a dangerous combination and usually a path to early death. For people with type 2 diabetes, gaining fat is also harmful and further worsens their condition.
Fructose may be helpful only in extreme cases—when a person is starving and at risk of imminent starvation within hours or days. In all other circumstances, anyone who wants to live a longer, healthier life should strive to avoid consuming it.