Sweet Potato Glycemic Index

Sweet potato GI ranges from approximately 44 to 94 depending on variety and cooking method. Boiled sweet potatoes (especially with skin on) are medium-GI (44–63). Baked or roasted sweet potatoes, particularly orange-fleshed varieties, can reach high-GI values (82–94). Purple and white sweet potatoes tend to be lower-GI than orange varieties. Because the range is so wide, we report it honestly rather than picking a single misleading number.

Sweet potato can be part of a diabetes-friendly diet when prepared and portioned carefully. Boiled sweet potato in a half-cup serving has a moderate GI and provides fiber, vitamin A, and potassium. However, baked sweet potato has a much higher GI and should be eaten in smaller amounts. People with diabetes should monitor their individual response and discuss serving sizes with their care team — this is general nutrition information, not medical advice.

Boiled sweet potato typically has a lower GI (44–63) than boiled white potato (78–89), making it a better choice for blood sugar control when prepared similarly. However, baked sweet potato can approach the GI of baked white potato. The fiber content of sweet potato (about 5 g per medium potato) is higher than white potato (about 3 g), which helps slow glucose absorption. In practice, preparation method matters more than the type of potato.

Yes. Orange-fleshed sweet potatoes (the most common variety in the US) tend to have higher GI values than white- or purple-fleshed varieties. Purple sweet potatoes contain anthocyanins that may slow starch digestion, and some studies report their GI as low as 40–50. White sweet potatoes are also generally lower-GI than orange varieties. If blood sugar management is a priority, consider trying purple or white sweet potatoes.

Sweet potato is moderate in carbs — about 26 g net carbs per medium potato. On a moderate low-carb plan (50–100 g net carbs/day), half a medium sweet potato fits comfortably. On strict keto (under 20–30 g net carbs/day), even a half sweet potato uses a significant portion of the daily budget. Most keto followers limit sweet potato to small amounts or avoid it in favor of lower-carb vegetables.

Yes. Cooling cooked sweet potato for several hours (refrigerating overnight) converts some of its starch into resistant starch, which is not fully digested and therefore has less impact on blood sugar. This effect is well-documented for potatoes and sweet potatoes. A sweet potato salad made with cooled, boiled sweet potato, lemon juice, and olive oil is a lower-GI option than freshly baked sweet potato.