Diabetes: The 40p food that 'significantly' controls blood sugar within minutes of intake

Some low GI foods, appreciate wholegrain foods, fruit, vegetables, beans and lentils, are foods we should always eat as a part of a healthy, balanced diet.

However, "using the glycaemic index to come to a decision whether or not foods or combos of foods are healthy are often misleading", says the NHS.

The health body explains: "Foods with a high GI aren't essentially unhealthy and not all foods with an occasional GI are healthy.

"For example, watermelon and parsnips are high GI foods, whereas cake incorporates a lower GI value."