eli5: why is potato chips so high in calories but potatoes are relatively low?
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Potatoes are actually pretty high in calories too, since they are mostly comprised of starch, which is a form of sugar. Potato chips however take this starch and then fry it in oil, so you are essentially adding fat to sugar, which is going to result in a very high calorie snack.
The potato isn’t the problem. 🙂 Chips are boiled in fat to get them crispy and some of that fat soaks into the potato. Fat’s about 9 calories per gram and because chips are awesome, those grams pile up fast.
It’s the oil that the chips are fried in. That’s where most of the calories in chips comes from. By weight, it’s also the relative ration of potato starches, etc. to water, which is reduced when frying.
Potatos don’t contain fat and have 75% water. So 100g potato is actually just 25g of food.
Potato chips don’t contain water which already multiplies the calorie amount by 4. Also during the frying process 50% fat is added which drastically increases the calorie count.
Normal potatos contain 70kcal per 100g.
If you dry them, 100g potato have 280 calories.
And if you add 50% fat to it (50g) you have 280kcal + 50g × 9kcal = 730 kcal per 150g. (1g of fat contains 9 kcal)
Devide that by 1.5 and you have 490kcal/100g which is a really close estimate to the real calorie count of potato chips.
Potato chips are high in calories because they’re fried in oil and have extra fat. Potatoes are low in calories because they’re mostly water and starch. The cooking method and added ingredients make the difference.
Potatoes have calories but they’re less concentrated, since most of the volume is water and fiber. Potato chips don’t have that (at least not nearly to the same degree a normal potato does), so you need to eat more of them if you’re trying to get as full as you would from eating a potato.
They used to be that way because they used to be boiled in typically lard / shortening/etc though nowadays a lot of the major brands have been switching to lower calorie oils like sunflower oil making this less of a concern
Oil. Oil has an insane calorie density. For reference, 100g (half a cup) of olive oil has same amount of calories as 3 ½ Big Macs.
u/HappyHuman924 has it spot-on, but there’s a little more consideration. Potatoes are mostly water. About 80%. So when you remove the water, as frying in oil does (the water boils off from the 300°F heat), the caloric density jumps from 0.87cal/gram to 4.35cal/gram. Given baked potato chips sit at about 4.20cal/gram, that helps showcase the impact that water has on caloric density.
Add the oil that stays on the chips, and you’re up to 5.36cal/gram.
This works with most other things. Beef jerky is much more calorically dense than steak. Banana chips more than their fresh counterparts. Water is a filler.
My doctor once told me to stop eating potatoes (a few decades ago). He explained that it wasn’t the potatoes that were the problem. But every time you eat potatoes they are deep fried in oil and covered with salt, or baked and then drenched in butter, cheese, bacon, sour cream, etc.
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