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Not everyone agrees with these established facts about grains and their impact on the body’s blood sugar and insulin levels, though, and will remind us of their supposed ‘essential’ nature for energy and life itself. Is this actually true?

Here’s an official list of the established essential elements in the human diet:5

 Water

 Energy

 Certain amino acids (termed ‘essential amino acids’)

 Certain fats (termed ‘essential fats’)

 Vitamins (such as vitamins A, C, D, E, K and B vitamins)

 Minerals (such as calcium, magnesium and iron)

 Trace minerals (such as zinc, iodine, selenium and chromium)

 Electrolytes (sodium, potassium and chloride)

However much we scrutinize this list, we will find no mention here of sugar, starch or carbohydrate. Part of the reason for this is that the mitochondria can burn alternative fuels (such as fat) for energy (more about this later).

It is true, though, that some of the body’s cells are totally dependent on glucose as they can burn no other type of fuel. However, glucose can be made from other things (notably, certain amino acids – the building blocks of protein) in the liver. It’s believed that the body can produce about 200g of glucose a day in this way – considerably more than we actually need. The fact is, technically speaking, the absolute requirement for glucose in the diet (from either sugar or starch) is none at all.

This does not necessarily mean that we should eat no carbohydrate, and it can play a role in the diet. For example, people engaged in certain forms of exercise and sports may benefit from carbohydrate (see Chapter 6 for more about this). However, basic physiology reveals that the idea that starchy carbohydrates are ‘essential’ for energy is simply wrong.

Some will still maintain, nonetheless, that grains are good for us because they provide ‘vital nutrients’. Again, does the evidence support this?

One way to assess the nutritional value of a food is to compare its nutrient content with the calories it contains. The idea here is that the best foods will be those of higher nutrient content but lower in the calorie department. This has led researchers to develop a concept known as the ‘nutrient density score’.6

Let’s compare the nutrient density scores of grains with those of other carbohydrate-based foods: fruits and vegetables. This figure represents the scores for fruits and veg. The healthiest foods are those that are positioned low (low energy density) and to the right (high nutrient levels) on the graph. Looking at the table we can see that fresh fruits and vegetables, with the exception of the potato, rate generally very well indeed.

Now, let’s take a look at the nutrient density scores for grains.

As you can see, generally speaking, grain-based foods are higher in energy density and lower in terms of their nutritional offering. This includes wholegrain foods such as wholemeal bread. The un-nutritious nature of grains is strongly hinted at by the fact that many of them (notably bread and many breakfast cereals) are ‘fortified’ with additional nutrients. If they were inherently nutritious, why fortify them?

In reality, grains provide us with no nutritional value that cannot be acquired more healthily elsewhere. And it’s also worth bearing in mind that some grains, notably unrefined wheat, contain substances called ‘phytates’ that block the absorption of nutrients such as calcium, magnesium and iron. Phytates compromise not only the nutritional value of grain, but also foods we eat with them.

The bottom line is that while many starchy carbohydrates are technically food, many are perhaps better described as fodder.