While potato (white, red, golden etc) are technically complex carbohydrate they are also very high glycemic (meaning the sugars in the potato are released rapidly. You can circumvent this partially by consuming them with lots of fats which will slow down the digestion of the potato.
Sweet potato is a much healthier option. And tastier!
Thank you sunyata for that added comment, I forgot to add that one. Sweet potatoes are definately the go, for lower GI in case of diabetics as well as the deep yellow ones (the flesh).
some more info:
All potatoes have a high glycaemic index – an unjustified
generalisation
However, as with all GI data, the GI values of potatoes may depend
on cooking method, processing, variety and the composition of the
meal (Lunetta et al. 1995; Fernandes et al. 2005; Foster-Powell et al.
2002). This fact deserves attention since mashed potatoes, French
fries, baked potatoes and potatoes cooked in a microwave are
characterised by GI values mostly exceeding the upper limit for a
high GI value of 70 (Fig. 1); whereas conventionally boiled potatoes
appear to have a GI value on average below 70. The values of conventionally
boiled potatoes do vary considerably though, so it may
also be that some potato varieties have an inherently low GI whatever
the cooking method (Najjar et al. 2004; Fernandes et al.
2005). In this context, it should be considered that most currently
available GI values are based on mature potato varieties (Ontario,
Prince Edward Island, Desiree, Pontiac, Sebago) (Hambloch,
2005). The starch of more mature potatoes is, however, easier to
digest, presumably due to increased amylopectin branching and
hence lower resistance to gelatinisation, which in turn results in a
higher GI (Soh & Brand-Miller, 1999). Finally, recent studies
have shown that potatoes consumed cold have a lower GI because
the digestibility of starch decreases with cooling, thus cold potato
preparations such as potato salad can be expected to have a low
GI (Najjar et al. 2004; Fernandes et al. 2005).
http://journals.cambridge.org/download.php?file
http://www.diagnosemefirst.com/Diet Glycaemic Index.htm