Everyone has heard about the harm of sugar to the human body, but few can explain the reasons beyond “it causes cavities and obesity.”
At the same time, the number of reasons counts in dozens, and if we believe scientific data, sugar indeed claims the title of “a product of mass destruction with a total effect on the human body.”
It is not for nothing that history knows several cases when representatives of the sugar industry initiated false research aimed at shifting the focus from the harm of sugar to the human body onto scapegoats in the form of “harmful trans and saturated fats.”
In this article, we will discuss numerous facts about the harm of sugar based on scientific research.
Main thoughts:
Sugar is harmful as it increases the risk of cancer: glucose is food for cancer cells
1 The harm of sugar to the heart
Most often, the main culprits of cardiovascular diseases are saturated fats containing cholesterol. Those more informed about modern scientific and medical advancements may also mention trans fats.
In 2016, a group of scientists from California revealed the fact that the Sugar Industry funded scientific research from 1960 to 1970, aimed at concealing the harmful effects of sugar on human health 5.
This was a kind of preventive measure against further stirring up controversy around sugar, as there was an increasingly growing interest in the media at that time regarding the harm of sugar to human health 4.
During this period, scientists from Harvard University – recipients of funding from the sugar industry – published several scientific articles that deliberately shifted the focus from sugar, as one of the main causes of cardiovascular diseases, to saturated fats and trans fats 5.
At that time, the conclusion of the compromised scientists sounded like this:
“Without a doubt, the only change in dietary habits required to reduce the risk of cardiovascular diseases is to consume less cholesterol and more unsaturated fats instead of saturated ones” 4.
Today, it is well known that consuming too much sugar significantly increases the risk of death from cardiovascular diseases, as it leads to obesity, inflammatory processes in the body, increases blood sugar levels, blood pressure, triglyceride levels, and “bad” low-density cholesterol – all of which are risk factors for heart and vascular diseases 3,10.
In a statistical study of over 30,000 people, scientists found that those who consume more than 25% of their total calories from sugar are 2.35 times more likely to die from cardiovascular diseases compared to those whose diet contains less than 10% of calories from sugar 2.
With a caloric intake of 2000 calories, 25% of calories corresponds to 125 g of sugar.
The recommended amount of sugar per day, according to the American Heart Association, for men is no more than 38 g (or 150 calories), and for women is no more than 25 g (or 100 calories) 1.
One of the most important factors of the harm of sugar to the human body is its impact on the cardiovascular system: its consumption in large quantities significantly increases the risk of death from cardiovascular diseases
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2 Sugar – one of the main causes of the obesity epidemic or The harms of sugar for weight loss
There are several explanations for why sugar makes us gain weight. And it’s not just about calories.
How sugar becomes fat
The body’s natural response to sweetness is an increase in blood insulin levels.
Insulin is a transport hormone. Its function is to control the level of sugar (glucose) in the blood.
How it does this: when sugar enters the body, insulin transports it into the cells to be used as energy. Glucose is the primary source of energy for cells.
If there is too much sugar, more than the body’s current energy needs, the excess is stored: in the glycogen of the liver and muscles. This is a quick energy storage.
When these stores are full, the body converts sugar into fat, which is stored, as everyone knows, in various places.
Thus:
The more sugar we consume, the higher the levels of insulin and glucose in the blood, creating more favorable conditions for fat deposition
But that’s not all.
“I want a lot of sweets…”
The caloric content of carbohydrates, including various types of sugars (table sugar, fructose) is about 4 calories. Just like protein. And this is half as much as fats.
But have you noticed that you always want to eat more carbohydrates, and sometimes it’s hard to stop? This doesn’t happen with proteins and fats (unless they are sweetened ;).
Sweet foods have a remarkable property: we want to eat a lot of them. It’s as if we lack a “Stop!” button to limit the consumption of sweets.
This is why they are easy to overeat, and this is why they are the number one enemy for weight loss.
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Why “I want a lot of sweets”
In our body, there is a hormone called leptin. One of its functions is to control the feeling of satiety. It’s not just the stomach that tells us we are full, but also this hormone, which acts on the brain.
The level of leptin in the body is proportional to the amount of fat, as it is produced by fat cells 6. This is a protective mechanism to reduce appetite to stop the process of consuming calories when enough has already been “stored.”
So why do we often see overweight people constantly chewing?
Under certain conditions, this mechanism for controlling the feeling of fullness can be “turned off.” This condition is called leptin resistance (analogous to insulin resistance).
This manifests in the fact that a person eats but does not feel full, which naturally provokes the consumption of excess calories and even greater weight gain.
Leptin resistance very often develops in people with obesity 6,7.
The second reason, which is directly related to the topic of this article, is eating habits, specifically the consumption of large amounts of sugar.
Have you noticed that when you eat something sweet, shortly after you want to eat again? That’s right. There are several reasons for this, but one of them may be the body’s loss of the ability to respond to leptin.
Of all types of sugars, fructose is particularly effective (harmful) in this regard: recent studies have shown that its consumption can lead to leptin resistance even in people with normal weight 6.
Let us remind you that the familiar table sugar consists of 50% glucose and 50% fructose. See our material Glucose, fructose, sucrose: what is the difference?
Today, fructose is becoming increasingly popular as a sugar substitute; it is added to products and even used to make jams.
The harm of sugar for weight loss or body constitution is explained by the fact that its consumption produces hormonal changes in the body that stimulate overeating.
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3 Sugar and the risk of diabetes
There is a clear relationship between sugar consumption and the risk of developing diabetes.
Obesity, which is often the result of excessive sugar and other carbohydrate consumption, is recognized by scientists as one of the main factors in the development of diabetes 8.
However, in practice, the relationship between obesity and diabetes is not always evident: in many countries, diabetes occurs in people with normal weight, and there are even cases where the prevalence of diabetes decreases as the level of obesity in the population increases 11.
There is a hypothesis that excessive sugar consumption (especially fructose) may be the main cause of diabetes in such cases 10.
Fructose is metabolized in the body in a special way. This occurs in the liver.
If there is a lot of fructose in the diet, the liver “becomes fatty” (see below) and inflammatory processes are activated in it. This affects the mechanism of insulin secretion and action in the body, leading to insulin resistance and diabetes 11.
According to statistical data, regular consumption of sugary drinks (carbonated and juices) significantly increases the risk of developing diabetes 12,13.
The harm of sugar to the human body manifests in an increased risk of developing diabetes. Fructose plays a particularly important role here.
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4 Sugar increases the risk of cancer
According to recent scientific data, sugar is one of the main causes of the development and progression of cancer in the human body.
Why? Because cancer cells also love sweets – sugar is a source of energy for their growth and division.
Known factors for cancer development include obesity and related inflammatory processes, high insulin levels in the body – all of which, as shown above, are determined by the amount of sugar in the diet 18.
Observations by scientists of the eating habits of more than 430,000 people over 7 years revealed that the consumption of various types of sugars is associated with an increased risk of different forms of cancer: excess sugar – with an increased risk of esophageal cancer, excess fructose – with the risk of small intestine cancer; all types of sugar – with the risk of pleural cancer and ovarian cancer in women 14.
The harm of sugar to the human body is also manifested in the increased risk of breast cancer in women.
Epidemiological data from the analysis of more than 15,000 cases of breast cancer show a clear relationship between the consumption of carbohydrates with a high glycemic index (including sugar) and the risk of breast cancer 15,16.
A possible cause is the same hormone insulin, the level of which rises with sugar consumption and leads to an increase in the level of another hormone – IGF-1, which stimulates the growth of cancer tumors 15.
In an experiment on mice fed a diet with sugar content comparable to that typical for a Western person, scientists showed that such a diet stimulates the growth of tumors in the breast and metastases in the lungs, as it activates inflammatory processes in the body 17.
In this study, 30% of mice that were fed a starchy diet had breast cancer; however, when the mice were fed a sugar-rich diet, cancer was observed in 50-58% of the animals.
Here, researchers also emphasize the special role of fructose in cancer development.
Sugar is harmful as it increases the risk of cancer: glucose is food for cancer cells
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5 Sugar is harmful to the skin
Sugar and acne
Scientific studies show that foods high in refined carbohydrates, primarily sugar, are directly related to the occurrence of acne.
Sugar raises blood insulin levels, which stimulates the secretion of male sex hormones (androgens), which in turn act on the skin’s sebaceous glands, increasing their secretion.
At the same time, the level of insulin-like growth factor (IGF-1) in the blood rises, which, according to statistical data, is proportional to the severity of skin damage from acne 19.
In a survey of 2300 teenagers in Turkey, 60% of whom had acne, researchers found that teenagers with clear skin have healthier eating habits.
Frequent consumption of sugar increases the risk of acne by 30%, fatty foods by 39%, and sausages and burgers by 24% 20.
Interestingly, skin problems in the form of acne are almost not characteristic of people (teenagers) living in rural areas 19.
Obviously, this is also related to the difference in the food that forms the basis of their diet: they generally do not have access to the latest culinary industry achievements in the form of milkshakes, ice cream, and other “sweet delights from McDonald’s,” but mainly consume natural products.
Sugar is harmful to the skin and is one of the factors in its damage from acne (the formation of pimples). For the skin of rural residents, skin problems are almost not characteristic due to the lesser availability of refined products.
Sugar and wrinkles or skin aging
There are about 300 scientific theories of aging in the body and skin.
One of them is the formation of so-called Advanced glycation end products (AGEs) – compounds that are the result of a chemical reaction between sugar (glucose) and proteins.
These compounds cause multiple disruptions in the body at the biochemical level, stimulating inflammatory processes, immune responses, cell growth, and disrupting the functions of proteins, fats, and enzymes, resulting in, among other things, the loss of the skin’s physical properties 25.
AGEs are formed in the body and can also be ingested with food. Consuming large amounts of sugar increases their concentration in the body’s tissues, which scientists believe leads to premature aging of the body and skin 26.
The consequence of excessive sugar consumption for health can be premature aging of body tissues, including the skin.
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6 Sugar affects emotional state, increasing the risk of depression
Our emotional well-being is influenced not only by the people and circumstances around us but also by processes occurring within the body.
Another negative consequence of excess sugar in the diet can be… depression.
According to statistical scientific studies, depression, even in a broader sense – mental disorders, occurs much more frequently in those who consume a large amount of refined food (including sugar and its derivatives) compared to those whose diet mainly consists of whole natural products 21,22,24.
What is the reason?
One possible cause of depression that scientists mention is the presence of chronic inflammatory processes in the body 23, which, as already mentioned, is characteristic of consuming a large amount of sugar.
The harm of sugar to the human body manifests in an increased risk of depression and other mental disorders when consumed in excessive amounts.
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7 Sugar and feelings of weakness
Have you noticed feelings of weakness and fatigue some time after a delicious dessert?
Why does this happen?
After consuming a large dose of sugar, the insulin level in the blood sharply increases, which, as expected, leads to a state of heightened energy 27.
However, this spike also ends as sharply as it begins, after insulin has done its job. As a result, blood sugar levels drop, and the body wants to eat again, leading to feelings of weakness.
This is a characteristic of food that is rich in sugar or fast carbohydrates but lacks protein, fiber, and fats: adding these ingredients slows down the digestion process, allowing nutrients to enter the bloodstream slowly, which keeps hunger at bay for a longer time 28. This is one of the principles of proper nutrition for weight loss.
To avoid such mood swings and feelings of weakness, avoid consuming only sweets (sugar): build your diet on complex carbohydrates and foods rich in protein and fiber.
One of the negative effects of excessive sugar intake on the human body is the feeling of energy depletion after its consumption. This does not occur after consuming complex foods based on complex carbohydrates, protein products, and fiber.
8 Sugar is harmful to the liver: “fatty liver”
Fructose has one significant difference from other types of sugars: its absorption involves the liver, whereas other simple sugars (glucose) are absorbed as they are.
Consuming a large amount of fructose increases the risk of developing so-called “fatty liver,” similar to that caused by alcohol consumption.
How does this happen?
For absorption, fructose must be converted into glucose in the liver. Sometimes, the accumulation of fat in the liver is explained by the fact that excess glucose is converted into glycogen and fat, which are “stored” in the liver.
However, scientific studies indicate that in reality, a very small percentage of fructose itself is converted into fat. But it has such an effect on the liver that, on one hand, it enhances the processes of fat creation in it, while on the other, it slows down its oxidation (burning for energy) 29.
Let us remind you that table sugar is 50% fructose.
What is the danger of fatty liver?
It exacerbates inflammatory processes in the liver, leading to irreversible damage similar to that caused by excessive alcohol consumption: its consequence can be cirrhosis and complete disruption of liver functions 30.
The harm of sugar to the human body manifests in an increased risk of developing fatty liver, the consequences of which can be liver cirrhosis and complete disruption of its functions.
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9 Other consequences of excessive sugar consumption for health
Among other facts about the harm of sugar to the human body are the following:
- Increased risk of kidney disease: according to statistical scientific studies, excess sugar (fructose) in the diet significantly increases the risk of chronic kidney diseases 31.
- Negatively affects dental health: bacteria living in the mouth feed on sugar; a byproduct of their activity is an increase in acidity, which leads to the leaching of minerals from teeth and increases the risk of cavities 32.
- Disrupts gut microflora: gut microflora or bacteria in the intestines are often considered a separate organ due to the significance of their activity for the human body, particularly for immunity. An excess of sugar leads to changes in it and the development of so-called “leaky gut syndrome,” which is not a strict medical term but describes a disruption in gut function with serious consequences for the health of the entire body 33,34.
Conclusion
Consuming too much sugar is undoubtedly harmful to human health. This applies to both table sugar and seemingly harmless fructose.
An excess of sugar significantly increases the risk of diabetes, cancer, obesity, disrupts gut microflora, harms dental and kidney health, and leads to the development of “fatty liver” similar to that of alcoholics.
We recommend reducing the amount of sugar in your diet, ideally eliminating it completely. Here are some tips on how to do this:
- eliminate or at least minimize all refined products made by humans, and try to base your diet solely on natural whole foods; practice shows that humans produce very little that is beneficial, not only in the food industry;
- feeling thirsty? resist the temptation to quench your thirst with sweet carbonated drinks (lemonade, cola, kvass, etc.) – plain water is better;
- add stevia – a natural sweetener – to your coffee and tea;
- instead of sweet yogurt and cottage cheese with excess sugar and flavorings, use unsweetened alternatives + frozen or fresh berries and fruits;
- instead of candies, try a mix of dried fruits (raisins, dates, apricots, candied fruits, nuts, and seeds);
- replace dry cereals with oatmeal topped with fresh fruits or dried fruits;
- don’t buy convenience foods from the store – you never know what’s inside; cook for yourself using natural ingredients.
