The very short answer to this question is yes. Sugar in it’s many forms is required by every cell of your body to live, to grow and to function. Various different sugars form vital components of many important proteins and even make up part of your DNA.
What is sugar?
Sugar is a generic name for a subclass of carbohydrates, which are macronutrients that supply the body with energy. There are several different sugars, however the one that comes up first in the mind of most people is cane or table sugar, also known as sucrose, called a disaccharide, because it is made of two simpler sugar molecules called monosaccharides. Slightly simpler sugars than sucrose, monosaccharides called glucose, fructose and galactose are the three major building blocks of all carbohydrates. Monosaccharides can join together to form complex carbohydrates. During the digestion process complex carbohydrates are broken down to these three components: glucose, fructose and galactose.1 Sucrose is composed of glucose and fructose bound to each other in 1:1 ratio. Sucrose is naturally made by green plants such as fruits, vegetables and nuts, through the process of photosynthesis (during which plants utilize energy from the sun into the food for their survival).
Globally, sugar is extracted from either sugar cane or sugar beet, since these plants naturally have the greatest ability to produce sucrose. While most plants, including fruits, nuts and vegetables contain around 10% of sucrose, the sucrose content in sugar beets and sugar cane is approximately 16% and 14%, respectively.2
Along with naturally-occurring pure sugar, there is a much-maligned form of sugar, known as high-fructose corn syrup (HFCS), which is made from corn.3 Unlike natural sucrose, it has higher fructose to glucose ratio and contains water as the other primary component. HFCS is a rather cheaper alternative to table sugar, thus it is a preferred option in the manufacturing process of many processed foods. Widespread use of HFCS in a wide range of foods is linked to increased sugar consumption, leading to weight gain and associated health complications. The FDA states that the percent daily value for added sugars should be no more than 10% of total calories consumed per day.3
Nutrition and healthcare professionals have raised concerns regarding potential health hazards of excessive HFCS consumption, due to danger associated with the increased proportion of fructose. Supporting studies have identified that consumption of HFCS and fructose had more negative outcomes when compared to consumption of glucose.8
Sugar’s role in the body
Sugar, in its many forms, is a critical component of all biological life from the construction of genetic material (like DNA and RNA), to cellular structure and cellular processes like respiration. Interestingly nearly all forms of life, such as bacteria, plants, animals and humans depend on metabolising glucose for their survival.4
Glucose is the major metabolic substrate for all mammalian cells.5 It is evident that all cells are able to absorb and use glucose, glucose enters cells through specific pathways, known as GLUT transporters that are present in the cell membrane.4 After breakdown of more complex sugars into glucose, glucose entering the blood becomes a building block for glycogen and adipose tissue (fat), glycoproteins, glycolipids, and nucleic acids (DNA and RNA). All of these are crucial resources of energy, some tissues (such as the brain) require glucose as an energy source to the exclusion of all other sources, while other tissues (such as muscle) utilise glucose to drive energy production in the form of ATP.5 Utilisation of glucose is also used for cell growth and survival. In particular, white blood cells (that are involved in our immune response), stem cells, and some epithelial cells.4
Does the body need sugar to survive?
The short answer is – yes. Each cell depends on glycogen and/or glucose to survive. Glucose is used as a source of energy and to support the increased rate of cell division and growth. Interestingly, across a tumour mass, interior cells may experience fluctuations in oxygen availability that in turn limit nutrient utilisation, becoming an important determinant of tumour survival. In addition, the increased glucose utilisation generates high amounts of lactate.2
Recommended daily intake of sugar
According to NHS England, the recommended amount of so-called “free” sugar consumed, i.e., sugar that is added to meals or drinks should not exceed 5% of the entire amount of calories consumed per day.6
Essentially this can be translated into the following:
- Average adult should only consume between 0 and 30 grams of free sugar a day
- Children below 6 years of age should only consume 19 grams of free sugar per day
- Children under the age of 4 are strongly encouraged to avoid sugar-containing drinks and processed foods containing added sugars
“Free” sugars come into our diet from foods like baked goods, sweets, cakes, chocolate, canned and fizzy drinks and juices. Sugars in honey, a variety of syrups (golden, maple, agave), nectars (blossom), occur naturally, however are still counted as free sugars. Alternatively, sugars in milk, vegetables and fruit do not count as free sugars.
It is important to keep in mind that both of these subtypes add up to the "total sugar" content of the food and can be found on food labels.6
Side effects of consuming too much sugar
In order to understand the link between increased consumption of sugar and the occurrence of disease, it is key to understand the complex relationship between food, blood sugar levels, insulin, and fat percentage of the body.2
After a meal, all complex carbohydrates are broken down into simpler monosaccharides (glucose etc.). Glucose is released into the bloodstream, which causes an increase in the blood sugar levels. As body senses increase in blood sugar it signals to pancreas to secrete the hormone insulin. Insulin controls the process of glucose uptake by all cells. While glucose fuels cellular needs, all the extra glucose is an important resource of energy and is stored in the liver and muscles as glycogen. When the storage capacity in the liver is full, the body continues storing glucose as fat, which often leads to weight gain.2
On the other hand, when there is no glucose release (such as between meals), blood sugar levels drop, causing the pancreas to secrete another hormone, glucagon. Glucagon breaks glycogen back down into glucose to provide energy for cellular metabolism. As all glycogen stores are used up, the body breaks down the fat as an energy source.
Certain foods rich in sugar or carbohydrates break down much more easily, leading to quick release of large amounts of glucose. As a result, an immediate spike in blood sugar occurs. The pancreas works particularly hard to compensate for the excessive amount of glucose, actually secreting too much insulin into the bloodstream.One outcome is fast absorption of glucose is therefore a rapid drop in blood sugar levels caused by the spike in insulin secretion, which can affect the energy levels, leading to feeling of tiredness and hunger.7 Extreme imbalance in blood sugar levels can eventually lead to impaired sensitivity of pancreatic cells and inability to produce insulin, as seen in type 2 diabetes.
Other health complications include weight gain, obesity, cardiovascular disease and even cancer. Cancerous cells undergo uncontrolled division and growth, and in presence of a high glucose environment growth of cancer tissue is favored.2
What happens if we don't eat sugar?
It is believed that limiting consumption of added sugars has numerous health benefits, including:9
High levels of energy
Table sugar is a simple carbohydrate, meaning that when digested, it results in an abundance of glucose that gets absorbed quickly. Although it can lead to an immediate burst of energy, after a short time it leads to an energy crash due to overcompensation by the pancreas (see above). This is called reactive hypoglycaemia. Cutting down on sugars and increasing consumption of other macro nutrients like protein can help to stabilize the blood sugar levels. This will result in durable high-energy throughout the day.
Improved skin health
As sugar has been linked to the process of inflammation, eating foods with a high glycaemic index can worsen skin’s potential to repair collagen. Collagen is a protein that maintains elasticity and hydration of the skin, preventing occurrence of wrinkles and signs of premature aging.
Healthy heart and kidneys
High blood sugar levels are dangerous for cardiovascular and renal health. Both heart and kidney function rely on the efficiency and health of blood vessels, particularly smaller delicate blood vessels. Reducing sugar and carbohydrates encourages prevention of uncontrolled inflammation, diminishes the release of reactive oxygen species (ROS) and improves sensitivity to insulin function. Another consequence of increased sugar consumption is weight gain, which can eventually resuls in high cholesterol and triglyceride levels.
Minimizing “free” sugar intake can therefore promote the maintenance of normal blood sugar, and thus a healthy heart and kidney health.
Maintaining healthy weight
Sugar is among the most caloric foods, therefore a diet full of sugars on a regular basis leads to weight gain and obesity. These complications can be controlled by following the guidelines regarding recommended sugar intake.
Tips to cut down on sugars10
Try to evaluate the amount of sugar and sugar-containing products (honey, syrups, molasses) you consume daily. Where possible, one can always cut back on the amount of sugar added to meals and drinks regularly, for example cereal, pancakes, coffee or tea. Instead of completely eliminating all sugars at once, think about cutting the usual amount of sugar by half at first. It is important to have a balanced, healthy and sustainable diet. 10
Avoid canned drinks. These can be good treats, however fizzy drinks often are rich in sugars and other flavorings. To stay hydrated, water is the best choice, swapping normal canned drinks for a diet alternative can be a better choice.
Consume a lot of fresh fruit, as well as dried and canned fruits (in water). These are good sources of sugar, which can satisfy one’s cravings. These also are high in fiber, which helps to control normal blood sugar levels.
Be aware of nutritional values and check nutritional labels. Aim to choose for foods with lower amounts of added sugars.
Rather than saying no to all desserts and baked goods, cut the serving size. Experiment with sugar levels. when baking at home. Most recipes can be modified by cutting down the sugar, without compromising the end result.
Have a balanced diet. Try to consume enough fiber and protein to manage your cravings. Often, poor diet can make you crave simple sugars unconsciously as it is the most easily available source of energy!
Substitute sugar with natural sweeteners. Stevia, is a naturally occuring extract with sweet taste, it does not cause rise in blood sugar, thus can be an alternative to sugar. Excessive consumption of stevia, however, can have unpleasant side effects, such as laxative effects.
In summary, sugar, in the form of glucose, has an enormous physiological role as primary source of easily available energy. Despite it being fundamental for healthy cell metabolism, excessive consumption of sugars is known to have detrimental health effects. In particular, consumption of processed foods rich in added sugars leads to disturbed energy levels, fluctuation in blood sugar levels, and can cause overeating, weight gain and other related health complications. Maintaining healthy blood sugar levels is key for prolonged vascular health and control of inflammation.
- Sugar. New Scientist [Internet]. [cited 2023 Apr 27]. Available from: https://www.newscientist.com/definition/sugar/.
- Nutrient Metabolism, Human | Learn Science at Scitable [Internet]. [cited 2023 Apr 27]. Available from: https://www.nature.com/scitable/topicpage/dynamic-adaptation-of-nutrient-utilization-in-humans-14232807/.
- Gearing ME. Natural and Added Sugars: Two Sides of the Same Coin [Internet]. Science in the News. Harvard University; 2015. Available from: https://sitn.hms.harvard.edu/flash/2015/natural-and-added-sugars-two-sides-of-the-same-coin/
- Archer E. In Defense of Sugar: A Critique of Diet-Centrism. Progress in Cardiovascular Diseases [Internet]. 2018 [cited 2023 Apr 27]; 61(1):10–9. Available from: https://www.sciencedirect.com/science/article/pii/S0033062018300847.
- Devaskar SU, Mueckler MM. The Mammalian Glucose Transporters. Pediatric Research. 1992 Jan;31(1):1–13.
- NHS. Sugar: the facts [Internet]. nhs.uk. 2022. Available from: https://www.nhs.uk/live-well/eat-well/food-types/how-does-sugar-in-our-diet-affect-our-health/
- Levy RB, Claro R, Moubarac J-C, Canella D, Martins AP, Louzada ML, et al. The big issue for nutrition, disease, health, well-being [Internet]. www.wphna.org. WPHNA World Public Health Nutrition Association; [cited 2022 Nov 19]. Available from: http://www.wphna.org/htdocs/2012_dec_wn3_food_system.htm
- Ari Magill. This Is What Happens When You Stop Eating Sugar for 14 Days [Internet]. seemayo. 2022 [cited 2022 Nov 19]. Available from: https://seemayo.com/this-is-what-happens-when-you-stop-eating-sugar-for-14-days/
- Wang G-J. Impact of sugar on the body, brain and behavior. Frontiers in Bioscience. 2018;23(12):2255–66.
- American Heart Association. Tips for Cutting Down on Sugar [Internet]. www.heart.org. 2018. Available from: https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/sugar/tips-for-cutting-down-on-sugar