America’s obesity epidemic can be traced to the 1980s, about the same time that Americans were told to reduce their fat consumption to 30% of calorie intake. What’s surprising is that Americans acted on this advice from the American Heart Association, American Medical Association, and the US Department of Agriculture but they got fatter and sicker. As fat consumption went down, obesity, metabolic syndrome, non-alcoholic fatty liver disease, cardiovascular disease, and stroke prevalence all increased. Why?

 

Researchers have discovered that sugar is the problem.

 

Much of the refined sugar consumed is in the form of sugar-sweetened beverages. Around the world, people drink an average of close to three 8-ounce sugary drinks per week.¹ An increase in the number of servings of sugary drinks per day is associated with higher body mass index (a measure of fatness) in children and higher body weight in adults.² Studies have shown that increased consumption of sweetened beverages led to greater weight gain, while subtraction of sweet drinks led to weight loss.³

 

White sugar is sucrose. Sucrose is made of one glucose molecule and one fructose molecule, so it’s a 50/50 split that happens when sucrose is broken down in the body. Half of the amount of sugar you eat becomes glucose, the energy of life, while half metabolizes to fructose.

 

Sucrose, glucose, and fructose all occur in nature. But as Dr. Robert Lustig says, “When God made the poison, He packaged it with the antidote.” It would be more accurate to say that God created whole foods and we made poisons, like refined sugar, from them by denaturing them. In nature, sugar is packaged with fiber and other essential nutrients. Fiber not only slows the release of sugar into the bloodstream but also leads to satiety, the satisfaction you feel when you’ve had enough to eat and don’t want more food.

 

The food industry strips the fiber and other nutrients that naturally come with the sugars because fiber reduces shelf life. Processed foods are made appealing by adding concentrated sugar and other flavor- and texture-enhancing ingredients. But processed foods with their high content of concentrated sugars don’t break down in the body in the same way that natural foods do.

 

 

Image via Unsplash.

 

The most prevalent sweeteners in processed foods are white sugar, or sucrose, and high fructose corn syrup or HFCS. HFCS is very similar to sucrose or white sugar and mainly only differs slightly in its ratio of fructose to glucose. While white sugar is made of equal amounts of glucose and fructose, HFCS used in baked goods is composed of 42% fructose to 58% glucose, while the HFCS used in soft drinks is 55% fructose to 45% glucose. White sugar and high fructose corn syrup are both bad and cause many of the same health problems as chronic alcohol consumption because of the way they’re processed in the body.

 

High fructose corn syrup came onto the market in 1975 and our consumption of it has steadily increased since that time. It’s sweeter than sugar and cheaper to produce. And it’s extremely prevalent in processed foods. Not only is it in sweet foods where you’d expect to find it, like in candy and soft drinks, but it’s in many foods where you might not expect to find it, such as infant formula, sauces and condiments, bread, and crackers. It’s also in foods that may be considered “healthy,” such as drinks made with fruit juice and in applesauce.

 

Processed sugars like white sugar and HFCS are anything but natural and they’re not “healthy.” Sugar is poison. Here’s why.

 

According to Merriam-Webster, “poison is a substance that through its chemical action usually kills, injures, or impairs an organism.”⁴ Over the long term, refined sugars kill, injure, and impair consumers through the chemical action of fructose upon the body.

 

Metabolism of glucose sugar

As we’ve seen, refined sugar, which includes white sugar and HFCS, is made up of glucose and fructose. Eighty percent of the glucose you consume is used by your body for energy. It is the main source of energy that your body uses for all its functions which is why it’s called the fuel of life. Glucose also stimulates the production of insulin, which in turn stimulates leptin, an appetite suppressant, letting your brain know that you’ve eaten and that you don’t need to eat anymore. The remaining 20% of the glucose consumed is processed by the liver.

 

Most of the glucose metabolized by the liver is stored in a form called glycogen. The liver can store an unlimited amount of glycogen with no ill effects which is why athletes can practice carb-loading without causing liver problems. A small amount is broken down to form adenosine triphosphate or ATP, and the waste product, carbon dioxide. ATP is the source of energy used by cells. The carbon dioxide produced by this reaction is exhaled. An additional small percentage of the 20% of glucose that ends up in the liver may be turned into very low density lipo-protein (VLDL), a bad type of cholesterol which contributes to obesity and heart disease. But only a very small amount of glucose consumed is made into VLDL.

 

The body’s response to and use of glucose is very different from that of fructose.

 

Fructose metabolism

Fructose is only metabolized by the liver, so 100% of fructose consumed is processed by the liver. It doesn’t stimulate insulin production, and therefore leptin is not produced to tell your brain that you’ve consumed calories and can stop eating.

 

The metabolism of fructose requires three times as much phosphate as the metabolism of glucose. The phosphate is taken from ATP, producing uric acid as a waste product. Uric acid causes gout and also leads to hypertension because it blocks the production of nitric oxide, our body’s natural blood pressure lowering compound.

 

Fructose consumption also has a greater impact on fat production than glucose consumption has. A study found that normal healthy adults put on a diet containing HFCS, experienced the following negative health effects in just six days:  triglycerides doubled, de novo lipogenesis (production of fat) increased by a factor of five, and free fatty acids which cause insulin resistance doubled.⁵

 

Compared to glucose, fructose:

 

• Is more likely to form advanced glycation end-products (AGEs).⁶ AGEs are proteins or lipids that have been changed by sugar and are prevalent in the blood vessels of diabetics and contribute to the development of atherosclerosis, the plaque build-up in artery walls. High levels of AGEs are also linked to inflammation, oxidative stress, Alzheimer's, and kidney failure.⁷
• Does not suppress the hunger hormone ghrelin.⁸
• Does not stimulate insulin and therefore does not stimulate leptin production. Leptin also suppresses hunger.⁹
• Promotes metabolic syndrome,¹⁰ a cluster of risk factors related to cardiovascular disease, that is, “diabetes, hypertension, heart disease, cancer, and dementia–the things that kill you under the concept of ‘metabolic syndrome.’”¹¹

 

The metabolism of fructose in the liver also leads to liver insulin resistance. Because your liver, fat, and muscle cells don’t respond effectively to insulin, your pancreas releases more in an attempt to help your body utilize the glucose you take in. The more insulin you produce, the harder it is for your brain to recognize the leptin which is produced to shut down the hunger feeling. This leads to continued food consumption because your brain keeps getting the signal that you’re hungry.  “Fructose consumption changes the way your brain recognizes energy, all in a negative fashion, so that you basically think you’re starving,” says Lustig.¹² At the same time, fructose also increases the reward signal. This is how fructose, in sucrose or HFCS, contributes to obesity.

 

A diet high in fructose has a lot in common with chronic alcohol consumption because both are metabolized by the liver in the same way. The main difference between fructose consumption and alcohol use is that alcohol produces immediate intoxicating effects on the brain, but fructose doesn’t. Nevertheless, eight of the 12 common disease states associated with alcoholism are also associated with diets high in fructose. These include hypertension (high blood pressure), myocardial infarction (heart attack), dyslipidemia (high levels of lipids or fats in the blood which is a significant risk factor for heart disease), pancreatitis (inflammation and swelling of the pancreas), obesity, liver dysfunction (which can result in toxins in the brain and decreased mental function, along with bleeding stomach and kidney failure), fetal insulin resistance, and habituation or addiction.

 

Sugar and heart disease

The death of former President Dwight Eisenhower from heart failure in 1969 sparked an intense research interest to determine the cause of heart disease. Researcher Ancel Keys proposed that dietary saturated fat was the chief culprit, while John Yudkin proposed that sugar was chiefly to blame. The Sugar Research Foundation downplayed evidence from a study Yudkin had done in 1957, resulting in a dismissal of Yudkin’s hypothesis. The result was that the public was informed that to avoid heart disease, fat intake, especially saturated fats, must be reduced. No warning was given based on Yudkin’s findings linking sugar intake with heart disease.

 

 

Even though cholesterol consumption has fallen over the past 50 years because of the perception that fat causes heart disease, heart disease has only increased, not decreased. However, the consumption of fructose has steadily increased, along with the rates of heart disease. Not surprisingly, a growing body of research has accumulated over the last few decades showing that Yudkin was right, after all. Sugar plays an important role in the development of heart disease. Here’s why.

 

The metabolism of fructose by the liver causes an increase in uric acid in the blood. Elevated blood levels of uric acid increase the risk of developing hypertension, high blood pressure. In addition, high blood pressure and higher levels of uric acid in the blood both increase the risk of atherosclerosis. Atherosclerosis is a chronic inflammatory disease in which the arteries become thicker and harder from the build-up of plaque. Plaque build-up decreases blood flow and can lead to heart attack and stroke.

 

In addition, fructose produces inflammation, not only in cells of blood vessels where plaque forms, but in organs throughout the body. The metabolism of fructose triggers an inflammatory response resulting in “gut inflammation, liver inflammation, and neuroinflammation.”¹³ Inflammation is a key factor in the development of diseases such as heart disease, cancer, diabetes, and neurodegenerative diseases such as Alzheimer's and Parkinson’s disease.

 

A common misconception is that sugar is only indirectly related to heart disease because eating too many calories leads to overweight, and being overweight causes heart disease. But this is a mistake. Sugar’s role in heart disease is much more direct, playing an active role in its development and progression.

 

In addition, sugar has been implicated in osteoporosis as well. Researchers have found that the overconsumption of sugar increases the urinary loss of both calcium and magnesium, lowers vitamin D levels, and impairs bone formation.¹⁴ 

 

When you eat refined sugar, you’re not just filling up with useless, nutrient-poor “empty calories.” It’s much worse because sugar consumption is associated with stroke, type 2 diabetes, non-alcoholic fatty liver disease, metabolic syndrome, and cognitive problems, among other health issues.¹⁵ Refined sugar offers no health benefits apart from the energy supplied by the glucose. Instead, it is a poison that should be avoided.

 

Most processed or packaged foods contain refined sugars, so read the labels and avoid them.

 

Refined sugars include:

 

• Sugar/sucrose
• High fructose corn syrup
• Agave nectar
• Brown sugar
• Cane sugar
• Evaporated cane juice
• Florida crystals
• Grape sugar
• Golden syrup
• Invert sugar
• Icing sugar
• Organic sugar
• Refiner’s syrup
• Yellow sugar

 

But is it necessary to completely eliminate sugar from your diet? Lustig doesn’t believe it is. “Your liver can process roughly six to nine teaspoons a day without significant issue,” he says.¹⁶ 

 

Nevertheless, many experts believe research supports a diet that is much lower in sugar than the amount that most of us eat. Nutritionist and naturopath Barbara O’Neill points out that through most of history, carbohydrates (the group of nutrients to which sugars belong) have taken time to prepare in the farm kitchen, but today, the food industry has made them into fast foods that require little time to prepare or eat. So we’re eating more carbs, or sugars, today than ever before. O’Neill, who follows a plant-based, high-protein, low-carb diet herself says, “They [carbohydrates] do not necessarily need to be eliminated but seriously reviewed.”

 

Because of the (deservedly) bad press that sugar has gotten in recent years, a whole industry has developed around the production of zero-calorie sweeteners and other sugar alternatives. Are zero-calorie and artificial sweeteners the answer? No, for several reasons.

 

Alternative sweeteners are often used in diet sodas and processed foods that contain refined flours, damaged fats, and a variety of chemical taste enhancers that are also bad for your health. In addition, sugar alternatives, even zero-calorie sweeteners, also mess with insulin production. Research shows that artificial sweeteners trick the pancreas into releasing insulin even when no glucose has been ingested. This leads to insulin resistance,¹⁷ a precursor to type 2 diabetes.

 

Is using natural sweeteners like honey, dehydrated cane juice, or dates better? While natural sweeteners are better in that they come with the essential nutrients God designed them with, the problem is the sugar itself. Your liver still has to process the fructose.

 

Your liver can handle only small amounts of fructose. Throughout history, intensely sweet foods were not commonly eaten. There was no refined sugar, honey wasn’t easy to get, and fruits were eaten mostly in season. Until more recent times, our livers did not have to deal with large quantities of fructose. The solution, it seems, would be to return to a simpler, whole foods diet that is low in all types of sweets; a diet in which natural sweets are not everyday indulgences but are enjoyed less frequently and in small quantities.

 

 

Note: This article is adapted frombased on a lecture by Robert Lustig recorded May 26, 2009 by University of California Television. Dr. Lustig’s research and clinical practice has focused on childhood obesity and diabetes. He has written and lectured extensively on how processed foods make us sick.