242. Sugar: the Number One Threat

If I am asked

“What is the first step to take to improve the nutritional quality of my diet?”

my answer is that you should reduce sugar intake as much as possible. But this may prove to be very difficult.

Lots of sugar

First of all, there is an awful lot of sugar out there. Every time I go to a supermarket I am appalled at sheer quantity of products that contain loads of sugar. There are soft drinks in abundance. A standard can of soda may contain as much as 60 gm of sugar. Some people drink several cans in a day. WHO recommends that the intake should be about 10% of Calories, which is about 50 gm per day, although a value of 5% would be preferable. Back to the supermarket shelves again and there are huge bottles of pop, which contain two or three litres that have to be transported into the store on pallets. I often see shopping trollies with many of these bottles and I just hate to think what the effect will be on the members of the household. Then we have all the sweets, chocolates and biscuits. All this before we get to the foods. Unfortunately, many of the processed foods such as ready meals, sauces and baked goods have sugar added during their manufacture. On top of all this, there are the “healthy” “low-fat” foods, many of which have replaced the fat with sugar.

Secondly, sugar is relatively inexpensive, which explains why it is used so widely as a “filler”.

Thirdly, many consumers have a “sweet” tooth and therefore find foods that contain sugar are attractive. Even worse, for some people sugar is addictive and may lead to other nastier drugs.

One of the major hurdles in trying to convince friends that sugar is dangerous to health is that people cannot perceive that such a widely used item of food could possibly be bad for health. A classic case of “familiarity breeding contempt”.

The case against sugar

There is now a very good understanding of what happens inside the body when sugar is consumed.

However the concerns about the dangers to health of consuming sugar have been around for many years.

USA science writer Gary Taubes in his excellent book, The Diet Delusion, provides the following examples of evidence that sugar contributes to the development of various diseases (1):

  • In 1924, Haven Emerson, director of the Institute of Public Health at Columbia University in New York, concluded that:

“Rises and falls in sugar consumption are followed with fair regularity within a few months by similar rises and falls in death rates from diabetes.”

  • In 1975, Richard Doll and Bruce Armstrong commented that:

“The higher the sugar intake, the higher the incidence of any mortality from cancer of the colon, rectum, breast, ovary, prostate, kidney, nervous system and testicles.”

    • In Israel, diabetes specialist Aharon Cohen found that in 5000 immigrants from the Yemen in 1949 there were only 3 cases of diabetes. By contrast, the incidence of diabetes in Yemenis who arrived about 20 years earlier was almost 50 times greater. Cohen concluded that the much greater consumption of sugar amongst those who had already settled in Israel was the critical factor responsible for difference in disease levels.


  • In South Africa, Dr. George Campbell, who was in charge of the diabetic clinic in Durban, observed that diabetes, coronary heart disease (CHD), hypertension and gall bladder disease were common in the local white population but virtually non-existent in the Zulus living in rural areas. Furthermore, as sugar consumption by the rural population increased, there was an increase in heart disease. In 1956, Campbell spent a year in Philadelphia, and discovered that the pattern of disease in the local black population was virtually the same as in the whites in South Africa. When he returned to Durban, he noted that Indian people working in the sugar industry had a high incidence of diabetes which he described as


“…almost certainly the highest in the world”.

  • In the UK, physiologist and nutritionists Dr. John Yudkin noted that the rise in sugar consumption preceded very closely the rise in deaths from heart disease.
  • Cancer: until recently, the 1920s work of German physiologist Otto Warburg, which concludes that glucose is essential for cancer cells to function effectively, has largely been ignored. Warburg showed that cutting off the supply of glucose was an effective way of tackling cancer. Today, researchers, such as USA biology professor Thomas Seyfried, are conducting investigations that provide convincing support for this concept.
  • Alzheimer’s Disease (AD): here again there are strong indications that excessive sugar is an important risk factor.  People who suffer from type 2 diabetes (T2D) may be up to five times more likely to develop AD compared to those who do not have the disease.

Incidentally, Gary Taubes has written another book, which is specifically about “The Case Against Sugar” that has just been published (2). I have yet to read it but the reviews indicate that it is another tour de force that is a comprehensive explanation of why sugar consumption should be limited.

T2D may be regarded as the tip of the iceberg because those who suffer from this disease have a much higher risk of developing the common chronic diseases than those who do not. The crucial factor is the build-up of glucose in the blood, which in turn triggers the secretion of insulin by the pancreas. When sucrose is digested it breaks down to glucose and fructose (fruit sugar). Robert Lustig, one of the leading campaigners for tighter controls on sugar explains that the glucose and fructose are metabolised in different ways, and therefore have totally different effects in the body. The glucose can be utilised by every cell in the body, whereas the fructose must be metabolised by the liver that converts it into fat. Essentially, the body metabolises fructose using the same biochemical pathways it uses to metabolise alcohol. Excessive amounts of fructose (and alcohol) causes the condition known as “fatty liver”, or non-alcoholic fatty liver disease (NAFLD).

As Taubes puts it:

“Because sucrose and high fructose corn syrup (HFCS-55) are both effectively half glucose, half fructose, they offer the worst of both sugars. The fructose will stimulate the liver to produce triglycerides (fat), while the glucose will stimulate insulin secretion. And the glucose-induced insulin response will prompt the liver to secrete even more TG than it would from the fructose alone, while the insulin will also elevate blood pressure (BP) apart from the effect of fructose.”


It is important to appreciate that sugar is not an essential nutrient. It is often presented as such by dietitians who argue that it is required in order to supply the body with energy. However, energy can be sourced from fat and protein. We know that there are populations, which consume little or no sugar (or any carbohydrates for that matter) that are perfectly healthy.

So while there may still be debate about the desirability and dangers of the starchy foods such as bread, flour, pasta and rice, we have now reached a point where we have a very powerful case for excluding sugar from the diet. In fact it is somewhat surprising that the UK Government has accepted that there is a case for introducing a tax to discourage the consumption of sugar. Anyone who would like some support in attempting to reduce sugar consumption might find it useful look at The SugarFree Revolution established by Karen Thomson in South Africa (3).


  1. G Taubes (2007). “The Diet Delusion” Vermillion London
  2. G Taubes (2016). https://www.amazon.co.uk/Case-Against-Sugar-Gary-Taubes/dp/1846276373/ref=tmm_pap_swatch_0?_encoding=UTF8&qid=&sr=
  3. http://www.thesugarfreerevolution.com/



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