Jimmy Mohamed demonstrated on France 5 in November 2024 that cooking methods alter the glycemic index of potatoes, raising values from 65 for steamed potatoes up to 95 for baked ones, while also explaining why baked potatoes can make blood sugar rise more rapidly.
In Plain English: The Clinical Takeaway
- Glycemic Index (GI): A scale ranking how quickly carbohydrates raise blood sugar levels compared to a reference food.
- Starch Gelatinization: A process where heat and moisture modify the structure of starch, making it more accessible to digestive enzymes charged with breaking it down into simple sugars.
- Resistant Starch: A type of starch formed when potatoes are cooled after cooking, which is less easily digested.
How Cooking Alters Starch Breakdown and Glycemic Response
During a broadcast of the Magazine de la Santé on France 5 in November 2024, Dr. Jimmy Mohamed discussed how the cooking method of potatoes affects their glycemic index.
Steamed potatoes yield a glycemic index of 65. However, turning those same potatoes into a purée pushes the glycemic index up to 90.
Prolonged heat in an oven pushes the glycemic response even further. According to the medical commentary presented on France 5, baked potatoes reach a glycemic index of 95. Le mode de cuisson a une véritable influence sur l’index glycémique. Prenons une pomme de terre cuite à la vapeur : son index glycémique est de 65. Si vous écrasez cette même pomme de terre en purée, il monte à 90,
he explained on the plateau, before adding, Le pire, entre guillemets, c’est la pomme de terre cuite au four : son index glycémique atteint 95. Il faut donc aussi être vigilant sur le mode de cuisson.
| Preparation Method | Glycemic Index (GI) Value | Structural Impact on Starch |
|---|---|---|
| Steamed | 65 | Maintains structure; slower enzymatic access. |
| Mashed (purée) | 90 | Structure disorganized; facilitates enzymatic access. |
| Baked (oven) | 95 | Intense heat increases starch digestibility. |
Practical Strategies for Managing Blood Sugar Response
These numerical values are indicative and shift based on the variety of potato, its maturity, its preparation, and the conditions of cooking. Consumers do not need to ban potatoes. Instead, modifying culinary habits can alter how the body absorbs the glucose.
Opting for steaming or cooking in water without prolonging the cooking time, and keeping potatoes in pieces rather than transforming them into a smooth purée, is recommended. Furthermore, allowing cooked potatoes to cool after cooking encourages the formation of resistant starch, which is less easily digested. Combining the potatoes with vegetables rich in fiber, a source of protein, and a suitable quantity of fats also helps to slow the absorption of carbohydrates.
References
- France 5. Le Magazine de la Santé. Broadcast featuring Jimmy Mohamed. November 2024.
