While eating a whole potato would seem on the surface to be a reasonably healthy choice compared with processed foods, spuds can be a dud when it comes to their effect on your blood glucose level. Many potatoes fall into the high range on the glycemic index, (GI) which measures the effects of foods on blood sugar. High GI foods, with a score higher than 70, cause your blood sugar to spike quickly. Medium-glycemic foods rank at 55 to 70 on the scale and have a modest effect on your blood sugar. Ideally, the majority of the foods you eat should be low on the glycemic index and have a value less than 55. These low-GI foods raise your blood sugar slightly over a longer period of time. Unfortunately, most potatoes rank higher than table sugar on the glycemic index.
Russet potatoes are some of the worst offenders when it comes to upping your blood sugar. Russets are the most commonly eaten potato in America. A baked russet has an average GI value of 85. If you eat the skin, it falls a bit lower, whereas peeling the skin away makes it as high as 111. Baked white potatoes have a glycemic index of 82. Instant mashed potatoes have a glycemic index of 87. Sweet potatoes have a glycemic index of 70. A better option is yams. Yams have an average GI of 54, meaning they’ll have less effect on blood sugar. Comparatively, table sugar has a glycemic index of 58. Remember, the higher the glycemic index or load, the higher and quicker your blood sugar raises. The higher and quicker your blood sugar rises, the more insulin your body releases to deal with the elevated blood sugar. Finally, high insulin levels lead to obesity.
Remember, potatoes are carbohydrates that are turned quickly into sugar by your digestive tract. This leads to elevated insulin levels and promotes obesity. If you do eat potatoes, also eat the skins, which lower the glycemic index of potatoes. Also remember, the longer potatoes are cooked, the higher the glycemic index. Cooking potatoes breaks down the carbohydrates, which makes the sugars more easily and quickly absorbed. Overall, avoid potatoes if you are trying to lose weight.