Different Types of Sugar
Sweet sugars – the type you put in your coffee, are difficult to spot outside of the supermarket. We refine the naturally occurring variety from sugar beet and cane to obtain a granulated product which is convenient to use. There are sugars in most other fruit and vegetables, which render them edible when ripe, eg about 7% in grapes, 2% in onions and tomatoes - and a mighty 30% in bee honey (1). These “natural” sugars are chemically identical to the refined variety, but represent a more modest assault on our palates compared to the amount we have developed a taste for over the last 150 years. Until refined sugar became affordable, there was no point in having a sweet tooth...
Some Sugary Facts
The first account of the solid product can be found on a Persian tablet dated 510 BC, but the value of sugar cane was known in Ancient India and China. Saccharum officinarum is the source of most of the world's sugar. It resembles the bamboo, but its stem is filled with a syrupy sap, a reserve food store for the rapidly growing plant which is a member of the grass family. During the 7th century, the Persians improved the refining process and began exporting sugar to the West, where it became an expensive delicacy. As cultivation spread, the price dropped and it was less of a luxury by the beginning of the19th century. During the Napoleonic wars, an alternative crop, sugar beet (Beta vulgaris) was cultivated under direct orders of Napoleon himself. After selective breeding, modern sugar beet contains up to 20% sucrose, which is higher than sugar cane at around 12%, but the yield of the latter is greater than that for sugar beet. Sugar cane refineries produce a range of useful by-products eg molasses and different grades of brown sugar, but sugar beet has no equivalent, just a foul smelling waste used for animal fodder.
Other Sources of Sugar
From the body’s point of view, sugars are just another source of energy, needed to drive chemical reactions inside cells and keep us alive and moving. If we eat only natural sugars, that’s fine, because there is plenty of energy in starchy foods such as breads, cereals and pasta. Starch is a different type of sugar, with long chain molecules - which do not dissolve easily in water. Hence they do not taste sweet and need to be digested by enzymes before they are absorbed by the body and used as a source of energy. Our ancestors exploited cereals to break away from the nomadic lifestyle and establish farming communities. Globally, we obtain 51% of our energy from cereals, while in the UK the figure is nearer 30% (2). Roots and tubers supply another chunk of energy, followed by pulses and fruits, vegetables oils and dairy products, where the latter provide energy from fats rather than starch.
Are There Other Sources of Energy?
If we were short of both starch and sugar in our diets, we would be in a bad way, but such is the versatility of our physiology, it can extract energy from surplus proteins in the diet, and if necessary it will start to break down proteins in muscles and organs, but we are talking about serious weight loss here. Obtaining energy from body fat is safer, but it is rather like accessing money from a deposit rather than a current account. If our intake of energy is a bit on the low side, the body permits the release of fatty acids from fat cells to make up the shortfall. This is a slow process, as anyone on a sensible weight-loss diet will know.
The loss of more than 1kg of fat per week is likely to tip the body into “starvation mode” with a reduction in overall metabolic rate, helping to conserve fat reserves rather than burn them off. This is why crash diets fail. The message for sugar addicts is - a little of what you fancy - in moderation - does you good!
References
- Fox B. Cameron A. (1995) Food Science, Nutrition and Health. Arnold.
- Millstone E. Lang T. (2008) The Atlas of Food. Earthscan Books.
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