The Sydney University Low GI Study
Tests on Australia’s five most popular varieties of table grapes by researchers at Sydney University prove grapes have a low glycaemic index. The glycaemic index (GI) is a ranking of carbohydrates on a scale from 0 to 100 according to the extent to which they raise blood sugar levels after eating. For example, pure glucose sugar has a GI value of 100.
Low-GI foods produce gradual rises in blood sugar and insulin levels, and have proven benefits for health. Low-GI diets have also been shown to aid weight management because they help control appetite and delay hunger.
The World Health Organisation (WHO) recommends that people in advanced countries base their diets on low-GI foods to prevent the most common diseases of affluence, such as coronary heart disease, diabetes and obesity.
The Sydney University study* measured the GI values of five varieties of grapes – Menindee Seedless green grapes, Flame Seedless red grapes, Crimson Seedless red grapes, Thomson Seedless green grapes, and Red Globe grapes.
Foods with a GI value of less than 55 are considered to be low GI foods. A GI value between 56 and 69 is deemed to be medium. Foods with a GI value of 70 or more are high GI foods.
Three of the grape varieties tested in the study (Red Globe, Crimson and Menindee) produced GI values ranging from 48-54, placing them in the low GI category.
The Flame and Thomson grapes produced average GI values of 57 and 58 respectively, placing them at the lower end of the moderate GI category.
The range of GI values produced by the five grape varieties in this study is consistent with the GI values of 43-59 noted for other green and red grapes.