Do Sweet Potatoes Have a Lower Glycemic Index Than White Potatoes?

Hi,
For years I have tried losing weight on and off by cutting carbs out of my diet, but each time this just made me feel terrible and I would gain the weight back as soon as I resumed my usual eating habits. Recently I've been trying to make lasting changes toward a healthier diet, like including more whole grains instead of white flour. It's been working to help me lose weight slowly but surely at a rate of about a pound each week. My question for you is, I've been replacing white potatoes with sweet potatoes because I think they have a lower glycemic index ... is this true?
--Tess B.

Dear Tess,

Congratulations on making changes for a more lasting healthy diet and on seeing the real results! When you set these healthy new standards that you can continue to follow you won't have to worry about going off a diet ever again.

The glycemic index of a sweet potato is, in fact, lower than that of a white potato: 55 for the former and about 75 for the latter. However, this number refers to the increase in blood glucose seen when ingesting the food by itself. Normally potatoes are consumed as part of a meal and the combination of various foods changes the overall effect on your blood glucose level.

There are advantages to consuming a diet that is composed of lower glycemic index foods in general. Many studies show that people who follow a low-glycemic index diet have a better time losing weight and body fat, and incidences of some chronic diseases are reduced as well. Furthermore, sweet potatoes contain a higher level of some nutrients than white potatoes, including more calcium, more vitamin C, and loads of beta carotene (not found in white potatoes) which turns to vitamin A in your body.

If you top baking potatoes with butter and/or sour cream when you have them, you'll also be saving these added calories if you have a sweet potato instead--unless, of course you are someone who likes brown sugar and butter on yours!

So, while avoiding white potatoes is not necessary to promote weight loss (they are still a good source of vitamin C, fiber, and complex carbohydrates) the sweet potato is a wise substitute to make on frequent occasions.

I wish you continued success with your healthy lifestyle changes and weight loss.