Fructose is a poison (part 1/2)

Why are we tying? Can a cola can and a beer can do the same? Why is not calorie equal to calories? Is weight loss related to calorie burning? Read the material written on the basis of a lecture by Dr. Robert H. Lustig, professor of pediatrics dealing with the treatment of obesity.


What causes weight gain?

Genetic factors and the environment. Our genes have not changed over the last 30 years, and it was at this time that there was an epidemic of obesity in the US. In Poland, overweight and obese people have also rapidly arrived in the last 30 years.

There is a widespread belief that to keep body weight at a constant level, you have to spend as much energy as it delivered to the body with food. It turns out that this is not true. In the US, there is an epidemic of obesity among six-month-old children, which probably never happened in the history of human species. So small children eat as much as they need and this food should satisfy their energy needs necessary for life, development and growth without causing weight gain. It’s different, but more on that later.

All people in civilized countries eat more than our ancestors ate. In the US, boys aged 2-17 eat an average of 275 kcal more than boys aged 5-10 years ago. Men eat an average of 187 kcal more, and women up to 335 kcal more. Why and where do these extra calories come from?

Fat intake among children in the US has increased in recent years by 5 g, which corresponds to 45 kcal, and carbohydrates by as much as 57 g, which gives 228 kcal.

In the eighties of the last century, there were (still apply!) Recommendations to reduce the amount of fat in the diet so as to provide 30 instead of 40% of energy. The Americans adhered to these recommendations, but this did not improve their health, quite the contrary. Along with the reduction in the amount of fat in the diet, the number of obese and overweight people began to increase, along with the number of cases of metabolic syndrome, non-alcoholic steatohepatitis, diabetes and heart disease. These changes resulted in “degreasing \ diet with simultaneous” enrichment “with carbohydrates.


Where in the diet excess carbohydrates?

In the US, among children and adolescents, consumption of sweet carbonated beverages increased by 41% over the last 10 years, and fruit drinks and juices increased by 35%. Most of these beverages (as well as sweets and sauces) contain glucose-fructose syrup, which is cheaper and sweeter than sugar. Americans eat an average of 28.5 kg of this substance, which was not used before 1975. In the food industry is also used pure fructose, whose sweetness ratio is 173 (sugar – 100, glucose-fructose syrup – 120, lactose – 15, glucose – 74).


Glucose-fructose syrup (HFCS) is metabolized similarly to the sugar which is poured into the sugar bowl, which creates the appearance that it is healthy. Meanwhile, HFCS and sugar are poison. They are not just empty calories, as they are said about them, they are harmful. Therefore, consumption of products containing glucose-fructose syrup or fructose damages two times – it provides unnecessary, empty calories and poisons the body.

Before introducing HFCS to the market, Americans ate 15-24 g of fructose from fruit and vegetables daily. After 1977, consumption almost doubled (37 g), and after 1990 reached 54.7 g a day, and its main source stopped being fruits and vegetables. Currently, as much as 15% of calories in the American diet comes from fructose.


Digression about cholesterol

Not everyone knows, but “bad” LDL cholesterol consists of two factions, of which only one is harmful. The level of neutral LDL raises the fatty diet. The level of really bad vLDL raises sugar in the diet. Thus, not always high levels of LDL are indicative of a health risk. High levels of LDL at low levels of triglycerides do not threaten health. On the other hand, high levels of triglycerides with low LDL are a health risk.


With the change of diet to low-fat people have switched to a diet containing large amounts of glucose-fructose syrup, fructose and sugar, which in 50% consists of fructose. Effect? The diet is lower by 2 g of fat per day, richer by 13 g of carbohydrates and 4 g of sugar.

Currently, we eat not only less fat, but fiber. Our ancestors – hunters and gatherers – ate 100-300 g of fiber a day. We eat it in quantities of … 12 g per day. This is because we produce food from refined grains that tastes better, cooks less quickly and has a longer shelf life. It is simply more convenient.



  1. It is 7 times more susceptible to the production of advanced glycation end products, so-called AGE’s.
  2. Fructose does not block the secretion of ghrelin – hunger hormone.
  3. Fructose does not stimulate the secretion of insulin or leptin.

Leptin is a substance secreted by the body that informs the brain that you have eaten. If we eat too much, there must be interference in the operation of leptin – the brain does not know that you have eaten, so it does not suppress the appetite and allows you to eat more.

  1. Hepatic hepatic metabolism is completely different from glucose.
  2. A diet rich in fructose promotes the development of metabolic syndrome.

Compare what happens after consuming 120 kcal from glucose, ethanol (alcohol) and sugar.

  1. Glucose 120 kcal (2 slices of bread)

The glucose value of 24 kcal will reach the liver (the rest will be burned by the body, including the brain), much of which will be stored in the form of glycogen – energy reserve. The liver can store huge amounts of glycogen without harming your health. Some of the glucose will be consumed by working liver cells, and some, about 1/2 kcal will be converted into fat and “bad” LDL – vLDL. However, the resulting amount of vLDL is negligible.

Glucose the body “sees and reacts to it with a decrease in appetite and the appearance of a feeling of fullness, which prevents overeating – leptin works properly.


  1. Ethanol

Ethanol is also a carbohydrate but also a toxin. It causes depression, heart rhythm disorders, fast breathing, dehydration, disturbs thinking and the correct way of moving. What effects can fructose cause for the environment and occurring immediately after consumption? None, because the brain is unable to draw energy from fructose and metabolize it. That’s why so few people know that it is no less harmful than alcohol.

Ethanol 120 kcal

Ethanol of the value of 96 kcal will reach the liver (the rest will be used by the body on an ongoing basis, e.g. in the brain – hence the symptoms of poisoning are quickly visible). Some of it will be transformed into acetaldehyde – a harmful substance damaging the liver, some will be converted into energy, some in vLDL, some in free fatty acids, which go to the muscles, lowering their sensitivity to insulin. A substance that causes inflammation will also be created.

The effects of alcohol abuse are, among others hypertension, heart problems, pancreatitis, dyslipidemia (elevated blood fat, including triglycerides), overweight, liver damage, damage to the fetus, falling into addiction.


  1. 120 kcal sugar (50% composed of fructose and 50% glucose) – a glass of orange juice

Glucose will go through the process described above (only 20% of glucose goes to the liver), but all fructose will go to the liver, because only it has the ability to metabolize it. Thus, sweet 72 (12 + 60) kcal with 120 kcal of sugar go to the liver. For starters, the liver metabolizes fructose, producing uric acid excreted in the urine. A large amount of uric acid causes hypertension and a disease called gout.

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