Yes and no.
Yes, because usually we eat them in the form of chips or crisps which means they are fried in the doubtful quality oil and have loads of salt. If you’re buying frozen chips or eating them in the pub or restaurant, the chances are they will be highly processed and with lots of additives. Either way, most of the time we have them cooked at high temperatures (too high for too long and carcinogens, such as acrylamide, start forming). Also, many potato products have high glycemic index. And almost always we peel the skin. For these reasons, potato is not even considered a vegetable by many nutritionists.
But no, they are not bad for you. It just depends on how you prepare and eat them. The best way to cook potatoes is lightly steaming – using a minimum amount of water and not throwing it away if there’s any left (water soluble compounds stay exactly there – in the water). Ideally, don’t fry or microwave them and don’t eat them mashed, especially don’t use instant mash (higher GI). Baking is the second best thing but try using lower temperature. And don’t get rid of the skin – that’s where all the fun is! Oh, and don’t eat green potatoes.
The humble potato actually contains a good amount of vitamin C (yes, that’s right!) and a great amino acid profile (surprise – potato has protein!). On top of that it contains B vitamins, potassium, magnesium, iron and obviously fibre. Spuds have lots of energy-giving carbohydrates, and contrary to common belief, not a lot of sugar (as long as you don’t overprocess it)! It fills you up and it’s cheap! What’s there not to like?
There’s even someone eating only potatoes for the whole year – and losing weight! Fair enough, he’s also eating sweet potatoes which are also great. Not that I recommend this particular diet [it’s just interesting as an experiment]! Variety is the key, and there are so many healthful foods out there. Are potatoes better than kale? Hm, probably not. But it doesn’t mean that potatoes don’t belong in the healthy diet.