Nutrition: how much carbohydrate

Tuesday 08 May 2018

This is a question that I am constantly being asked by visitors. It seems common knowledge that it is advisable to cut down or eliminate sugar and sugary food from the diet for many reasons but there is a lot of confusion over carbohydrates in general.

What are carbohydrates and what do they do?

When I write about carbohydrates these are the grains and cereals and foods made from them that make up part of our diet. Carbohydrates are called macro nutrients the same as fats and protein foods. They are called macro nutrients simply because they are measured in grams as opposed to micro- nutrients used to measure vitamins and minerals.

Carbohydrates are used primarily as a source of energy. The whole grain varieties are a good source of B vitamins and fibre in the diet. When we look at how much we are recommended to eat it is worth noting that there are different types of carbohydrates that have different effects on our health. I have written previous blogs looking at sugar or simple carbohydrates and what is called complex carbohydrates. If you refer to these for details you can see quite clearly that it is the complex carbohydrates that are the preferred option rather than the simple sugary carbohydrates.

All carbohydrates whether simple or complex end up after digestion as glucose. It is just that the complex carbs take longer to become glucose. With this in mind it is worth looking at what some experts say about the inclusion of any carbohydrates in the diet whether complex or simple. There are mixed opinions which does not help us but once we have looked at what the experts say we can draw our own conclusions.

Sugar and cancer

Many of you will have heard the sweeping statement that sugar feeds cancer. Well it is not the sugar but the glucose and as we know all carbohydrates eventually end up as glucose. Hence the rationale behind many complementary therapists and professors of nutrition who recommend very small and sometimes no carbohydrates in the diet. This understanding came from research by Otto Warburg in 1931 called the Warburg effect for which he was awarded a Nobel Prize. His research led to the belief that cancer cells behaved very differently to normal cells in the way that they make and use energy. Normal cells have the ability to make energy from either fats, proteins or carbohydrates and this happens in a very controlled way with in the cell using oxygen. Warburg came up with the theory that cancer cells only use carbohydrates (glucose) as a source of energy in the absence of oxygen.

The Ketogenic diet

One diet that was born out of this theory is the Ketogenic diet. I know many complementary practitioners who advocate this for their cancer patients. I wrote about this way of eating previously which you might like to refer to. Basically it is a diet high in good fats, some protein and carbohydrates only making up 5% of the diet and the carbs coming from non -starchy plant foods. Not a grain in sight!!! (By good fats I mean using high levels of avocados, cold pressed olive oil, flaxseed oil , nut butters like almond nut butter or cashew nut butter and so on).

Not all nutritionists of course concur with this method of eating and that is where the confusion lies. Many diets advocate very large amounts of vegetables with some fruit because vegetables contain not only vitamins and minerals but also phytonutrients many of which have been shown to have positive anti -cancer effects.

Vegetables also help to raise the oxygen levels in the body because of their high levels of potassium and magnesium. We do know that cancer cells do not thrive as well when oxygen is present. If you think about this, vegetables, particularly the root varieties, contain a considerable amount of carbohydrate so this would go against the theorist who advocate the ketogenic diet. Looking at this from another prospective many experts also advocate eating a high proportion of their protein from pulses (peas, beans, and lentils as opposed to the animal forms like meat, eggs and fish),which contain a considerable level of carbohydrate.

Mediterranean diet

Then of course we have the Mediterranean diet. This advocates a high level of colourful fruits and vegetables, lots of olive oil and whole grain carbohydrates mainly in the form of sour dough bread. I was reading the summary report by the World Cancer Research Fund published in July this year and this recommends avoiding high calorie sugary foods but eating lots of whole grains. Vegetables fruit and beans.

Confused about diets?

So, are you confused? It is easy to see how this can happen. It is of course not my place to persuade anyone one way or the other. I do think that common sense has to prevail and I am a huge believer in adopting a healthy way of eating that does not cause stress and a way of eating that is sustainable.

This of course would be different for different people. Some may adopt a ketogenic way of eating and find it easy and natural but for some it would be very foreign and cause a lot of confusion (I have seen this first hand) and cause a lot of stress trying to maintain it. Some may become vegetarian, others may genuinely miss meat.

So, when making up your mind, the advice I would give is to be comfortable with what you have chosen but recognise that processed foods, damaged fats and sweet sugary foods are best avoided or kept to a minimum. Simply because they have no nutritional value, can lead to tiredness and fatigue and suppress the immune system. Try to adopt a diet using foods that are as near natural as nature intended as our cells like natural and function better this way and remember that we are not super human and sometimes life gets in the way of our good intentions.

Also remember that any change in the right direction however small will be of benefit and other changes can come later and at a pace to suit you and what is going on in your life at the time.

Blog originally written by Caroline November 2016

Links updated March 2021

Since this blog was written, the debate about Sugar and cancer and research has continued, Cancer Research UK's article gives a useful overview of the current evidence which reminds us that we need glucose to fuel our cells.  They go on to suggest that the link between sugar and cancer is more complex and the biggest impact of sugar on cancer is an indirect one through weight gain caused by excessive added sugar in diets rather than from foods which naturally contain sugar. 

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