One reason we love sweet foods is the taste for sugar originally conferred major survival advantages on our ancestors. It enabled them to distinguish between edible and toxic substances (the sweet were likely to be edible, the bitter more toxic).

In a feast or famine environment, sweet foods supplied energy in a quickly accessible form. Unfortunately, we no longer live in a feast or famine environment, so this genetic urge doesn’t work so well. Today, we have too much of a good thing and the challenge is to help your body cope with the sugar assault.

Sugar is a general name for carbohydrates and there are literally thousands of different types of carbohydrates. There are the monosaccharides (glucose, fructose and galactose), the disaccharides (sucrose or table sugar, lactose or milk sugar, and malt, ferment from barley) and polysaccharides forming the starches, brans (cellulose) and glycogen.

Starches are broken down mainly to the monosaccharide glucose that we use for energy. Foods such as grains, vegetables, fruits, legumes, nuts and seeds provide complex carbohydrate, a wealth of nutrients and valuable fibre. Simple carbohydrates are found in sugar, honey, syrup, some components of fruit, white bread, refined foods, chocolate and lollies.

Cellulose (fibre) is an essential part of our diet, yet it’s considered a non-nutrient — in other words, we cannot digest it. What fibre does in humans, however, is absorb water, various toxins and the byproducts of digestion and excretes these in the stools. Fibre is also important to prevent constipation.

Carbohydrates are made of carbon, hydrogen and oxygen. They are the ideal dietary source of fuel for most body functions and their nutritional value varies over a wide range. Carbohydrates can be stored as sugars (glycogen) for short-term energy and the excess as fat for a long-term energy source. Glycogen is particularly stored in the liver and muscles. In a healthy person, the liver can store 8 per cent of its weight as glycogen.

The storage of large quantities of carbohydrates is inefficient, which means we need to eat them regularly. However, it’s the glycogen storage that enables you to get things done between meals. Without it, you wouldn’t be able to do anything except eat to maintain your energy. Fats are a much more efficient form of long-term energy storage, which is why all the macronutrients (carbohydrates, proteins and fats) are eventually stored as fat if you eat excessive amounts of food.