eli5: why is potato chips so high in calories but potatoes are relatively low?
In: Other
Life Pro Tip: get in the habit of reading the ingredients and nutrition information on foods that you buy.
(If you buy foods without nutrition labels, you can always find info about similar products online.)
The label on a bag of potato chips, for example, will tell you that nearly all the calories come from the fat they are fried in, and also that a small serving will give you most of the salt that it’s healthy to eat in a day.
(Potato chips are delicious, of course, because we evolved in an environment where both calories and salt were hard to get, so we needed to consume them when available.)
Most chips are just a vehicle to attach as much grease and salt as possible. The thinner the chip, the higher the ratio of grease and salt, the tastier.
People are saying it’s fat but that’s really very low. What’s actually causing it is the relative weight of a chip vs a potato once the water has been removed.
A few google searches show the numbers line up pretty evenly no matter what you look at, so:
28 grams of fried potato chip is about 150 calories
28 grams of baked potato chip is about 140 calories
28 grams of uncooked potato is about 22 calories. That’s because it’s heavier due to the water content. If you dehydrated the potato you’d end up with about 140 calories per 28 grams, even without frying it
Because potatoes are 80% water by weight, and most of that water is removed during the process of turning them into chips. Much of it gets replaced by oil.
Frying the potatoes changes/ reduces the resistant starch (basically starches we can’t digest but are actually good for us). Coupled with the loss of water from the spuds, they become more calorie dense and the oil they are fried in only adds more calories
They’re cooked in oil. When they’re cooked this way, they lose a lot of water and absorb a lot of oil – so you’re replacing something that has zero calories (water) with something that has about 9 calories per gram.
Most raw ingredients are mostly water. In a hundred grams of potatoes there are about 78 grams of water and about 20 grams of carbs. Because frying takes almost all the water out of the original potato and adds some fat so what’s left is basically pure carbs, fat, and salt.
So 100 grams of chips is 250 g of potato then frying out almost 200 g of water and replacing it with 40 g of oil.
As others have pointed out, one of the reasons for high calorie density is due to the potato chips drowned in oil before and after cooking. Another factor contributing to the calories is condiments additions such as calories from salt, sugar, spices, and protein. For example, 10 grams of sugar is 40 grams.
Latest Answers