The Not So Sweet Side of Added Sugar and Cancer

The Not So Sweet Side of Added Sugar and Cancer
The Not So Sweet Side of Added Sugar and Cancer

60 g: The average amount of sugar that South Africans eat daily 1. 

This works out to a whopping 12 teaspoons per day! 
It is scary to think that sugar is one of the top three most commonly eaten foods in a South African’s diet, alongside sugar-packed foods like cakes, biscuits, sweets, chocolates and cooldrinks. 

Sugar is part of the carbohydrate food group, and, along with fat and protein, carbohydrates are one of the three food groups essential to human health. 

Sugar is mainly made up of glucose and fructose.

Added sugar may be in the form of fructose, like the much cheaper and sweeter man-made high fructose corn syrup.

What is the Problem with Too Much Added Sugar?

The problem comes in when a big chunk of our carbohydrate intake is not from healthy carbohydrates like fruit, wholegrains, and legumes, but rather in the form of added sugar. 

While a little bit of sugar is not a cause for concern, the trouble is that our modern diets are packed with hidden sugars.

Experts believe that the liver handles the fructose in added sugar in a way that is damaging to our health (causing fatty liver disease which in turn is a leading cause of metabolic disease), especially in those who are overweight/obese or inactive. 

Added refined sugar causes a quick spike in blood glucose, triggering a host of metabolic changes in the body like kickstarting the inflammatory processes that can over the long-term be linked to chronic disease like cancer, as well as heart disease and diabetes.2 Because high sugar foods are low in nutrients and fibre, this means that a high-sugar diet can be low in nutritional value, affecting our overall health and nutritional status. 

And of course, eating excessive amounts of sugar may also lead to weight gain. 

This is because sugar does not have much impact on our satiety (meaning you do not get full on sugar) and is also high in energy (calories/kilojoules). 

In addition, we tend to eat sugary foods with other high energy foods, such as washing down a chocolate with a sugary fizzy drink when at a party.

As you develop your FQ (Food Intelligence Quotient) you will notice that you are generally hungrier the day after a high sugar treat day.

What is the Link Between Sugar and Cancer?

When we consume large amounts of sugar on a regular basis, this moves into the blood stream quickly and causes a spike in blood glucose (and insulin to deal with the sugar spike).

This directly triggers a host of metabolic changes in the body that kickstart the inflammatory processes of the body, and possibly leading to insulin resistance in the long-term. Insulin resistance occurs when the cells of the body, like muscles, fat and liver do not respond well to insulin and cannot use glucose properly. 

It is also thought that sugar stimulates the production of free fatty acids in the liver, the resulting compounds of which can trigger inflammatory processes. 

This may lead to cell and DNA damage called oxidative stress. 

Scientists believe that oxidative stress is what may play a central role in cancer.

The other way that sugar may indirectly be linked to cancer is through weight gain. 

This is because sugar does not have much impact on our feeling of fullness yet is high in energy. We also tend to eat sugary foods with more sugary foods, compounding the problem. 

Together, this may mean we eat too much energy (kilojoules/ calories) leading to an increase in body fat. 

There is strong evidence that being overweight or obese increases the risk various cancers4 such as cancer of the mouth, pharynx, larynx, oesophagus, stomach, pancreas, gall bladder, liver, colon, breast (post-menopause), ovary, endometrium (womb), prostate and kidney. 

Studies have shown that as much as 1 in 5 of all cancer deaths5 may be related to excess weight. 

It is estimated that by 2030, obesity-related cancers will have the highest death rates 5of all the cancers.

For this reason, the World Cancer Research Fund3 recommends that we limit our intake of sugar-sweetened drinks, aiming to avoid these beverages all together if possible.

What About the Sugar in Fruit?

It is important to note though that natural sugar like the fruit sugar called fructose has not been linked to cancer.

We know that when eaten as a whole fruit, fructose is digested and absorbed very differently to added sugar. In fact, many foods containing natural sugars, like fruit and vegetables, are high in nutrients that are potentially cancer protective,6 such as phytochemicals (e.g. carotenoids, phenolic compounds), vitamin C, vitamin E, minerals, fibre, and other bioactive compounds.3;4 

Scientists think that it is a combination of these factors working synergistically in whole fruit and vegetables that helps to reduce cancer risk.

And while fruit and vegetables can directly provide anti-cancer nutrients, these healthy foods may also have an indirect role in helping us maintain a healthy weight. Low in energy (kilojoules/calories), rich in fibre, with the ability to displace high energy/nutrient poor foods from the diet, it is clearly a double whammy of weight maintenance and cancer prevention when you include fruit and veggies in your diet.

Studies have also shown that fruit and vegetable lovers are less likely to smoke, be overweight, drink less alcohol, and are more active. Each of these factors play a role in managing our cancer risk.

Did you know?

Almost all professional strict body builders and beach body competitors, aiming for very low body fat levels, do recommend a number of fruit and vegetable servings per day. We must not demonise all carbs and certainly not eliminate fruit and veg from a balanced diet. Be careful of fad diets that do not promote long term healthy eating habits. Aim for 365 days of balanced eating rather than 2 weeks of extreme dieting where you will fall off the wagon early.

The FitChef Difference

Our FitChef EatClean Range meals are mostly free from added sugar in the quest to help manage our cancer risk:
  • Occasionally, for added sweetness, we use a touch of honey and rely on the natural sweetness of fruit.
  • We use only high fibre, whole grain starches. There are no refined carbohydrates in FitChef meals, which trigger a host of metabolic changes in the body that kickstart the inflammatory processes that may be linked to cancer.
  • Energy and portion controlled to manage weight, a key recommendation in managing our cancer risk.


  1. Mchiza ZJ et al. A Review of Dietary Surveys in the Adult South African Population from 2000 to 2015. Nutrients. 2015;7:8227-50.
  2. World Health Organization. Guideline: Sugars Intake for Adults and Children. 2015. Available at World Cancer Research Fund/ American Inspiration for Cancer Research. Diet, Nutrition, Physical Activity and Cancer: A Global Perspective. Continuous Update Project Expert Report. 2018. Available at
  3. Word Cancer Research Fund/ American Institute for Cancer Research Continuous Update Project Export Report 2018. Body Fatness and Weight Gain and the Risk of Cancer. Available at
  4. Font-Burgada J, Sun B, Karin M. Obesity and cancer: the oil that feeds the flame. Cell Met Rev. 2016;
  5. Hurtado-Borrosa S et al. Vegetable and Fruit Consumption and Prognosis Among Cancer Survivors: A Systematic Review and Meta-Analysis of Cohort Studies. Adv Nutr 2020;11:1569–1582.
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