209. Curing and Preventing Cancer with Diet

Despite the enormous resources devoted to research, there has been little or no progress in devising methods for the successful treatment of cancer. Effectively we have surgery, chemotherapy and radiotherapy all of which have serious limitations. Consequently the vast majority of patients diagnosed with cancer have a very poor prognosis.

Flawed approach

The fundamental flaw in the conventional approach is that there is almost complete failure to address the actual causes. This means that even if a tumour has successfully been removed by surgery the chances of a recurrence remain high unless steps are taken to identify the basic causes and eliminate them as far as possible. As David Servan-Schrieber (1) explained it is crucial to consider the lifestyle factors.

Critical role of diet

There is absolutely no doubt that the type of habitual diet being consumed is absolutely critical with respect to the risks of developing cancers and many other diseases. The big problem for most people is to decide what foods to include in a diet which will lower the risks of and possibly even cure diseases such as cancer. Unfortunately we cannot rely on the official bodies because their record is appalling. Readers of this blog will be aware of many examples, such as the acceptance of the cholesterol “theory” which underpins the recommendations to reduce saturated fats and increase the polyunsaturated fats (2). Despite the fact that this “theory” just does not stand up to any kind of rigorous examination, the advice continues to be promoted.

Recovering from cancer

I have just been reading an excellent book by Raymond Francis which explains how to prevent and reverse cancer (3). The author was given only weeks to live by the medical establishment but as a result of his own research he discovered information which he used to alter his lifestyle and as a result recovered completely. Since then he has written the book and is now a recognised leader in the field of optimal health maintenance. I should emphasise that there are 3 main areas which relate to cancer, namely stress, toxins in the environment (including food) and nutrition. In this blog I will restrict my comments to nutrition and here is a selection of the topics covered. Francis emphasises that the cells in the body will inevitably malfunction unless they have all the nutrients they need to perform their complex tasks. In his view the Standard American Diet, which is not all that different from the UK version just will not sustain healthy life. Official US data confirm that well over half of all Americans do not consume the recommended daily allowance (RDA) for zinc, magnesium or vitamin B6. Furthermore the actual RDAs are only a minimum requirement and may not be enough for optimal health. Many of our common processed foods such as white flour, refined sugar and white rice only provide calories and very little other important nutrients. On top of this nutrients have been reduced because of the intensification of agriculture and the growth in the production of foods prepared by manufacturing processes. There are also losses incurred because of the long time between harvesting and consumption.

Which foods help to overcome cancer?

Nevertheless there are many foods which are undoubtedly beneficial. A diet composed mainly of fruit and vegetables can reduce the incidence of cancer by 50% or more. Vegetables and herbs such as broccoli, cabbage, ginkgo biloba and garlic can prevent cancer and may even stop the growth of cancer cells.

Which foods to avoid?

There are also many foods which should be avoided. It is now well established that cancer cells differ from the other cells in the body because they are totally dependent on glucose as a source of energy. Essentially this means that if the cancer cells are starved of glucose then they can no longer thrive and multiply. In order to achieve this it is necessary to avoid sugar, which is present is a wide range of foods, including fruit juices and many “low fat” products where the fat has often been replaced by sugar. Foods which contain starch which is broken down to glucose must also be restricted if not avoided altogether. Sugar is particularly damaging to health because it also releases fructose which is handled in a different way by the body and almost certainly results in obesity and heart disease (4). Excessive intake of glucose increases the production of the hormone insulin which switches on cancer.

Most processed oils including those which “lower cholesterol” should be avoided. As explained in a previous Blog (5) the ideal omega-6: omega-3 should be close to unity. However in modern day diets the ratio may be as high as 20 or even 30, because there is so little omega-3 and excessive amounts of omega-6. It certainly does not make sense to increase the omega-6s. This imbalance will initiate and perpetuate inflammation, which is involved in virtually all chronic diseases, especially cancer. As the omega-3 levels in foods produced by intensive agriculture are relatively low, Francis recommends fresh organic vegetables, fruits, raw nuts and organic fish and meats.

As a general rule, Francis argues that the American diet has too much animal protein and that wheat should not be consumed. To avoid cancer there should be a high consumption of fresh plant foods. He actually advocates that 80% of the diet should consist of raw fruits and vegetables. In particular he concludes that the cruciferous vegetables: broccoli, cabbage, Brussels sprouts, mustard greens, kale and cauliflower are the most important in reducing the risk of cancer. Others that are also beneficial include carrots, onions, beets and spinach. Good fruits include avocados, cherries, blackberries, blueberries, pineapples, melons, kiwi fruit, mangos and plums. However because fruit contains sugar these should be consumed in moderation. For the same reason, fruit juices should be avoided.

It is important to appreciate that this is just one individual’s assessment of how a healthy diet should be constructed. Because there are so many different opinions on this topic it is extremely difficult for the ordinary Joe Public to decide on his/her own diet.


Nevertheless certain key messages do seem to be coming through from many different sources. First of all there are compelling reasons for concluding that many of the official guidelines do not stand up to rigorous examination and are wrong. As a consequence many people are choosing foods which they have been advised are” healthy” but in reality are doing more harm than good. A good example is polyunsaturated fat which is promoted as “healthy” but as explained above actually is a cause of inflammation. Secondly, it is clear that sugar should be regarded as toxic for most people and that intake should be kept as low as possible. This is certainly not reflected in official recommendations. In fact the EU has just approved a health claim for fructose, which is likely to result in increased consumption of sugar (6).Thirdly, vegetables are a particularly valuable group of foods and their importance is certainly not being emphasised enough in the rather bland message conveyed by “Five-A-Day”.

So while I would not necessarily endorse everything in this book, it certainly makes a very valuable contribution to the debate and it is a very worthwhile read.



  1. https://vernerwheelock.com/47-anticancer/
  2. https://vernerwheelock.com/6-the-rationale-for-reducing-fat-is-fundamentally-flawed-part-2/
  3. Raymond Francis (2011) “Never Fear Cancer Again: How to Prevent and Reverse Cancer” Health Communications: Florida ISBN 13: 978-0-7573-1550-3
  4. https://vernerwheelock.com/127-beware-of-fructose/
  5. https://vernerwheelock.com/15-are-polyunsaturates-good-for-you/
  6. http://www.efsa.europa.eu/sites/default/files/scientific_output/files/main_documents/2223.pdf




Scroll to Top