Research

Hormonal

Rapidly Available Glucose (RAG) is a superior predictor of in vivo glycaemic response compared to Glycaemic Index (GI) because it accounts for the absolute amount of glucose absorbed per serving rather than just the digestibility rate.

To better control blood sugar, look at the Rapidly Available Glucose (RAG) of foods rather than just their Glycaemic Index (GI). RAG measures the actual amount of glucose likely to be absorbed from a standard serving. For example, instant potatoes have a high GI (fast absorption) but low RAG (low total carbs per serving), whereas white rice has a moderate GI but high RAG (high total carbs). Prioritize foods with lower RAG values per serving to minimize blood glucose spikes.

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The measurement of RAG in vitro provides values for direct calculation of the amount of glucose likely to be rapidly absorbed in the human small intestine and, thus, to influence blood glucose and insulin levels. These values can be used to compare foods, as eaten, on an equal-weight basis.
Hans N. Englyst et al. · British Journal Of Nutrition · 1996

Why this rating

Strong correlation (r 0.760, P < 0.001) between in vitro RAG and in vivo GI across 39 foods, though the study is observational/correlational rather than a direct interventional trial.

Source

Measurement of rapidly available glucose (RAG) in plant foods: a potential<i>in vitro</i>predictor of the glycaemic response

Hans N. Englyst et al. · British Journal Of Nutrition · 1996

DOI 10.1079/bjn19960137

mechanism_only · n=39Cited 344×
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DOI resolved against Crossref · corpus check 2026-06-10

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