How Does Sugar Affect Your Health?

Sugar has become a ubiquitous part of our everyday lives. Found in a wide range of food and drinks on store shelves, the sweet ingredient can be difficult to avoid. Around 80,000 years ago, the only sugar source in our diets came from naturally-occurring fruit sugars such as fructose. Back then, sugar was only available for the few months in the year when fruits were in-season. Today, we have access to sugar whenever we want it, thanks to advancements in agriculture and food science. The ease with which we can get our hands on sugar today would have made our hunter-gatherer ancestors envious, but it comes with a price.

Childhood and adolescent obesity have been on the rise in recent years, with a growing body of research pointing to the long-term health impacts of consuming too much sugar. To help separate the fact from fiction, here are some things you may not have known about sugar.

Free sugars

In the UK, we consume many “free sugars”, and they are known for causing a range of health problems. These sugars may be added by the food manufacturer, a chef, or at home. Sugars in syrups, fruit juices, smoothies and honey may be found naturally but still count as free sugars. The sugar found naturally in fruit, veg, and milk does not count as free sugar.

A big revelation

In 2016, researchers discovered a scandal within the sugar industry. Companies had been sponsoring Harvard’s research papers throughout the 1960s, minimizing the adverse health effects of sugar and blaming the increased heart disease on fats. (1)

Suspicion around the previous research started to grow after a 2014 study found a solid link between heart disease and sugar consumption. The relative risk of dying from heart disease was more than double for people who got more than 21 per cent of their calories from added sugar. (2)

More than just a heart problem

In recent years, the risk of obesity and Type 2 diabetes have become well-known risks of consuming too much sugar. A lesser-known risk can be the toll the sweetener can take on your liver.

As the body’s filtration system, your liver is responsible for processing everything that enters your bloodstream through the wall of your digestive tract. Nonalcoholic fatty liver disease (NAFLD) happens when fat builds up within the liver, preventing normal functioning. Tuft University found a greater risk of developing NAFLD in people who consume just one sugar-sweetened drink a day. The risk was much lower in the group that avoided soft drinks with added sugars. (3)

By avoiding sweetened beverages and cutting sugar intake, the severity of NAFLD can be reduced. (4)

Stomach health and microbiota

Beyond the liver, sugar appears to have an impact on gut health. A healthy stomach will contain a range of microorganisms that assist with biological processes, including digestion. The bacteria form a ‘microbiota’ that works like a separate organ, aiding metabolism.

When the balance of good bacteria and harmful bacteria is upset, a person can experience health problems that extend beyond their stomach.

The last decade of research paints a picture that shows changes within the gut microbiota being caused by sugar. Overeating sugar can accelerate yeast and unhealthy bacteria growth within the gastrointestinal tract, leading to damage to the intestinal wall. The damage caused by sugar in the gut may trigger obesity, amongst other metabolic disorders. (5)(6)

According to one study, using pre- and pro-biotics to reduce intestinal inflammation can affect obesity and even some liver injuries when tested in mice. (6)

Reducing sugar intake and balancing your diet

For a healthy and balanced diet, reducing the amount of sugar in our diet can significantly affect our well-being. However, cutting down on our sugar intake can seem daunting. A lot of foods and drinks contain added sugar without us even being aware of it. Thankfully, there are more resources available online than at any other time for anybody looking to reduce their sugar intake. The NHS Change4Life website has helpful tips for cutting back on sugary drinks. (7)
The Food Scanner mobile app can be a great help for seeing what sugars your food contains. The app can scan barcodes on food packaging and track the amount of dietary sugar you are getting. (8) With the number of health resources available online today, everybody has the power to decide the amount of sugar they have in their daily diet.


  1. Kearns, C.E., Schmidt, L.A. and Glantz, S.A. (2016). Sugar Industry and Coronary Heart Disease Research. JAMA Internal Medicine, [online] 176(11), p.1680. Available at: https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2548255 [Accessed 11 Mar. 2021].
  2. Yang, Q., Zhang, Z., Gregg, E.W., Flanders, W.D., Merritt, R. and Hu, F.B. (2014). Added Sugar Intake and Cardiovascular Diseases Mortality Among US Adults. JAMA Internal Medicine, [online] 174(4), p.516. Available at: https://pubmed.ncbi.nlm.nih.gov/24493081/ [Accessed 11 Mar. 2021].
  3. Tufts Now. (2015). Daily Sugar-Sweetened Beverage Habit Linked to Non-Alcoholic Fatty Liver Disease. [online] Available at: https://now.tufts.edu/news-releases/daily-sugar-sweetened-beverage-habit-linked-non-alcoholic-fatty-liver-disease [Accessed 12 Mar. 2021].
  4. Vos, M.B. (2014). Nutrition, nonalcoholic fatty liver disease and the microbiome. Current Opinion in Lipidology, [online] 25(1), pp.61–66. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3947892/ [Accessed 12 Mar. 2021].
  5. Frazier, T.H., DiBaise, J.K. and McClain, C.J. (2011). Gut Microbiota, Intestinal Permeability, Obesity-Induced Inflammation, and Liver Injury. Journal of Parenteral and Enteral Nutrition, [online] 35(5_suppl), pp.14S20S. Available at: https://pubmed.ncbi.nlm.nih.gov/21807932/ [Accessed 12 Mar. 2021].
  6. Ochoa, M., Lallès, J.-P., Malbert, C.-H. and Val-Laillet, D. (2014). Dietary sugars: their detection by the gut–brain axis and their peripheral and central effects in health and diseases. European Journal of Nutrition, [online] 54(1), pp.1–24. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4303703/ [Accessed 12 Mar. 2021].
  7. NHS Choices (2021). Lower sugar drinks for kids. [online] Available at: https://www.nhs.uk/change4life/food-facts/healthier-snacks-for-kids/lower-sugar-drinks-for-kids-stop-tooth-decay [Accessed 12 Mar. 2021].
  8. NHS Choices (2021). Sugar. [online] Available at: https://www.nhs.uk/change4life/food-facts/sugar#be-food-smart-app [Accessed 12 Mar. 2021].

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