Carbohydrates are our main source of energy and one of the pillars of our diet (alongside fats, proteins, vitamins, minerals, trace elements and water): they cover between 40 and 45% of our energy needs and are essential for the brain, muscles and intestines to function properly. Yet they are increasingly blamed for weight gain and obesity — here’s how to separate fact from overindulgence.
The three families of carbohydrates
There are three kinds of carbohydrates: simple carbohydrates, complex carbohydrates, and polyols (sweeteners).
Simple carbohydrates
These fall into two groups. Monosaccharides are made up of glucose, fructose, galactose or tagatose. The best-known disaccharides are lactose, maltose and sucrose.
Simple carbohydrates are cariogenic and are a source of empty calories: ideally, they shouldn’t make up more than 10% of total energy intake. Fructose (from fruits and vegetables) is the exception, as it’s an important source of minerals and nutrients.
Complex carbohydrates
This category includes polysaccharides (found in minimally refined or wholegrain cereal products, which are the ones to favour) and oligosaccharides.
Polyols
Polyols (or polyalcohols, glycols) are chemical compounds used mainly in the food industry to make sweeteners (sorbitol, xylitol, mannitol). Low in toxicity, less caloric than refined sugar while giving a similar taste, they don’t trigger insulin secretion — making them a good option for people with diabetes or on a diet. On the downside, they’re not very easy to digest and can cause bloating and diarrhoea.
The role of carbohydrates in the body
Carbohydrates keep the brain running properly and power muscle contraction. They also play a part in synthesizing ribose, which is essential for DNA formation.
What happens when you overdo it?
A diet too high in carbohydrates (especially simple sugars) raises daily calorie intake. If that increase isn’t matched by more physical activity, the body converts the carbohydrates into fat, encouraging weight gain.
Why does the food industry add so much sugar?
Sugar is used in the food industry for two main reasons: its preservative power and its pleasant taste.
Better preservation
Sugar slows the growth of many micro-organisms, which helps preserve products for longer while also giving them a better texture.
Better taste
Sugar’s pleasant taste helps balance out bitter or sour flavours — food manufacturers also use it to mask the taste of certain lower-quality raw ingredients.
Carbohydrates cover 40 to 45% of our energy needs — but past 10% simple sugars, the balance tips toward storage rather than energy.
