DIET DOCTOR #20

Is there a real difference between sweet potatoes and baking potatoes

September 8, 2009
DIET DOCTOR #20

Q: At the gym I train at there are a number of female trainers that are either fitness or figure competitors, as well as male trainers that are competitive bodybuilders. My trainer is a fitness competitor, while my husband's trainer is a male bodybuilder. My question is regarding the diets that our trainers put us on. They are fairly similar with lots of chicken breast and broccoli. But the major difference is that my trainer has me eating sweet potatoes, while my husband's trainer has him eating plain baked potatoes. Is there a real difference between sweet potatoes and baking potatoes? And if not, can I just switch to baked potatoes to make our lives easier when it comes to shopping and cooking?

A: To start, yes there is a difference between white (baking) potatoes and sweet potatoes. The major difference is in their rate of digestion. White potatoes are extremely high on the glycemic index, which means they digest fast and jack up blood glucose levels and send insulin levels skyrocketing. While that's a good thing immediately after workouts, at other meals it can spell disaster for your physique. That's because a spike in your insulin levels, when you're not immediately recovering from a workout, puts a halt on fat burning and increases fat storage. That is not the best bet for your physique, as it could lead to serious fat gain. The sweet potato on the other hand, is a low-glycemic food. So it's slow digesting and does not jack up blood glucose or insulin levels. That means that it allows you to get some long-lasting energy from carbs without shutting down fat burning and increasing fat storage. The sweet potato is also rich in the antioxidant, beta-carotene. Besides being a potent antioxidant, beta-carotene is responsible for aiding growth and repair of the body’s tissues, which includes muscle. It’s also the high carotenoid content that gives the sweet potato its color. As far as you switching to baked potatoes, I would suggest a better option is for your husband to switch his white baking potatoes for sweet potatoes. His trainer is likely more interested in overall muscle gain without emphasis on fat loss. However, since the sweet potato provides about the same carbs and calories as white potatoes (about 160 calories and almost 40 grams of carbs per medium potato) it will provide all the carbs he needs for mass gain with less gain in body fat. If he wants to enjoy a baked potato, he can do so immediately after workouts when those fast carbs will aid muscle recovery and growth. Plus the high potassium content (over 900 mg per medium potato) of the white potato can further aid muscle recovery.

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