The GI diet is a weight-management and healthy-eating plan built around the glycaemic index — the ranking of carbohydrate foods by how fast they raise blood sugar. Followers favour low-GI foods such as oats, lentils, apples, and wholegrain breads, which release glucose slowly and steadily, over high-GI foods like white bread, sugary cereals, and potatoes, which spike blood sugar and — the theory goes — trigger the crashes, cravings, and fat storage that drive overeating. The approach has genuine merit for blood-sugar control and is endorsed in diabetes guidance, but critics note the GI of a food shifts with ripeness, cooking, and what else is eaten, and that low-GI junk food exists. As ever, overall dietary pattern matters more than any single index.