Two separate studies, in the US and New Zealand, have shown that sugar has a similar effect on the brain as nicotine and cocaine. Foods with a high glycaemic index (GI) cause blood-sugar levels to spike, and trigger a ‘rush’ that stimulates the same areas of the brain involed in nicotine addiction.

People consuming 10 per cent or more of their energy from added sugar were at risk of higher levels of triglycerides – a fat found in the bloodstream, and were 50 to 300 per cent more likely to have low levels of good HDL cholesterol, say US researchers.

Sugar-sweetened drinks can lead to high blood pressure, a UK study found.

Research shows that continued exposure to high blood sugar levels speeds up the ageing process and has an inflammatory effect on the body, increasing the risk of everything from arthritis to premature wrinkles.

Soft drinks are particularly harmful to tooth enamel because they contain both sugar and acid – a lethal combination that increases the chance of dental decay and enamel erosion.

Insulin allows glucose to enter cells from the bloodstream and tells the cells to start burning glucose instead of fat. Having too much glucose in the blood is highly toxic and one of the reasons for complications of diabetes, like blindness.

This is also known as insulin resitance, which is believed to be a leading driver of many diseases including metabolic syndrome, obesity, cardiovascular disease and type II diabetes.

Research on human subjects is scant, but animal studies have shown that sugar suppresses immune responses. More research is needed to understand the exact mechanisms; however, we do know that bacteria and yeast feed on sugar and that, when these organisms get out of balance in the body, infections and illness are more likely.