Although we are advised that free sugars should make up five per cent or less of our daily calories, studies show that for some this figure may be greater than 20 per cent.

Tooth decay is perhaps the most recognised side effect of excess sugar consumption. But eating too much free sugar can lead to a vast array of complaints, both physical and psychological.

Sugars fall into two categories, those naturally occurring in foods such as milk, whole fruits and vegetables, which are part of a balanced diet, and free sugars, typically added to products to enhance their flavour and appeal.

Milk, fruit and vegetables contain nourishing minerals, vitamins and fibre, so although we should be aware these contain sugar, we don’t necessarily need to reduce our consumption. However free sugars have no nutritional benefit, hence are not an essential dietary requirement.

Using sugar cubes as an example, adults should consume no more than seven sugar cubes per day, equivalent to 30 grammes. This amount is less for children. Yet the average can of cola contains nine sugar cubes-worth of free sugars, with children and teenagers high consumers of fizzy drinks.

Free sugars occur in several products you might not necessarily associate them with, such as ketchup and other condiments, as well as foods assumed to be healthy, such as flavoured yoghurts and certain breakfast cereals. Once a fruit is juiced, its sugars become free, and it loses much of the fibre contained in the whole fruit.

Free sugars have a high glycaemic index (GI), so they produce spikes in blood sugar levels, combated by a rapid rise in insulin production to return them to normal. Whole sugars have a low GI, releasing their energy in a more controlled manner, with steadier levels of insulin in the bloodstream.

While you feel fuller for longer with low GI foods, those with a high GI leave you hungry, at the same time reducing the effect of the 'satiety hormone' leptin, which lets you know you are full.

The effect of diet on acne has long been debated. Some says it is solely due to the hormonal changes of puberty; others argue it is entirely a consequence of poor diet. The reality lies somewhere in the middle.

While hormonal alterations increase the production of sebum (oil) and change the bacteria on the surface of the skin, excess free sugars have been shown to drive androgen release, increase oil production and promote inflammation. In populations where processed foods are not yet available, acne is almost non-existent. Diets high in refined sugars have also been shown to accelerate the ageing process through their effects on collagen and elastin.

Weight gain can result from excess sugar consumption. This is often stored around the middle. Inside the liver, excess sugar cannot be converted to glycogen, the product which when broken down releases glucose into the blood to increase your energy levels. Instead, it gets stored as fat. Non-alcoholic fatty liver disease (NAFLD) is on the increase and is overtaking alcoholic liver disease as the leading cause of liver failure.

Inflammation is one of the causative factors in the development of atherosclerosis (damage to blood vessels) and high blood pressure. High blood sugars, obesity, and inflammation are all associated with increased risk of certain cancers.

The negative effects of excess consumption of free sugars are so far reaching that it has been shown to result in anxiety and depression, poor sleep and even the development of dementia.

Perhaps the simplest advice that can be given for controlling your intake of free sugars is to prepare meals from scratch where possible, rather than turning to processed foods and those where you are unsure of the ingredients.

Easy swaps are switching fizzy drinks with a high sugar content to those where the label clearly states 'no added sugar'. A 150 ml glass of fresh juice will count as one of your five a day, but drinking lots of fruit juice or smoothies will increase your consumption of free sugars.

When reading the labels, sugars are either represented as 'Carbohydrates/ of which sugars...' or using a traffic light system, red being high sugar content. Sometimes the amount of free sugar is not easily apparent. If so, try to look for the levels of 'added sugars'.

As with many lifestyle alterations, success may lie in gently modifying your diet, initially cutting out sugars where you are less likely to notice the difference, while also allowing yourself treats at the appropriate intervals.