Food processing shows no association with glycaemic index, load

A recent study has found no difference in glycaemic index (GI) and glycaemic load (GL) between processing levels according to NOVA classification. However, GL is lower in ultraprocessed grains and vegetables than minimally processed foods (MPFs).

Researchers collected GI and GL values produced by healthy individuals for 1,995 food items from published sources and manually coded these by processing levels using NOVA classification. They also coded food items into eight groups: beans, nuts, and seeds; beverages; dairy; fats and sweets; grains; fish, meat, and poultry; and vegetables. Multilevel linear modelling was used to determine significance.

The effect of food processing on GI and GL contradicted the hypothesis of the study, with no significant difference in mean values across processing levels: GI–MPF: 54.1, processed food: 53.2, ultraprocessed food: 49.3 (p=0.712); GL–MPF: 17.1, processed food: 15.8, ultraprocessed food: 11.5 (p=0.890).

No significant association was noted between processing level and GI within food groups (p=0.184), but GL showed an inverse relationship with grains and vegetables (p<0.001).

“Any potential adverse outcomes associated with UPF are unlikely to be related to effects on glycaemia,” the researchers said. 

"GI and GL are measures of the quality and quantity of carbohydrates in food based on their effect on postprandial blood glucose,” the researchers said. “Diets high in UPFs and GI/GL are associated with chronic metabolic diseases but the relationship between them is unclear.”