The humble potato is a staple of diets throughout the world. It originated in Peru before spreading through the world in the 1500s. Some historians credit it with ending famine in Northern Europe and even with fueling European imperialism. It is easy to grow, stores well, and is versatile and tasty.

Early cultures boiled, mashed and roasted potatoes. Belgium and France both claim to have been first to make "French fries", although other nations including Chile and Spain have claimed credit. What is less disputed is that 20th century American fast-food chains are responsible for proliferating fries around the world. 

A couple of weeks ago, my daughter and I embarked on a mission to find the best fast-food fries.  If you're new here, this is our fourth such mission.  Check out the results from our chicken sandwich, milk-substitute, and sweetener taste-offs.

Americans eat about 110 pounds of potatoes per year, or about 2 pounds per week on average. Almost half of those potatoes are sold frozen, 85% of which become French fries. So, Americans eat an average of about 40 pounds of fries per year. Potato consumption has dropped 15% in the last 20 years, with essentially all of the decline occurring in fresh potatoes.

Potatoes comprise a relatively small percentage of total calories in both the US and in the world as a whole. Wheat contributes 5-6 times the calories as potatoes. Potatoes and rice contribute similar amounts of calories to US diets, but rice dominates in the rest of the world. Vegetable oils, sweeteners, and dairy each contribute at least four times the calories of potatoes. 

The northwestern states of Idaho and Washington comprise 60% of the US potato crop.

The volcanic soils Idaho's Snake River Plain and Washington's Columbia River Basin, combined with the local climate and availability of irrigation water, make these regions especially suitable for growing potatoes. Contrary to popular perception, however, Idaho is not all about potatoes. They grow other things too, including sugarbeets, wheat and alfalfa. 

So, who makes the best fries? 

On a recent Saturday afternoon, my daughter and I drove to the Arden Arcade area of Sacramento where there are six fast food restaurants within a couple of blocks. In order, we visited KFC, Jack in the Box, McDonalds, Chick-fil-A, In-n-Out, and Burger King. At each restaurant, we ordered a medium fires at the drive-thru window. We immediately pulled into a parking spot, tasted the fries, and rated them out of 5 on each of the following criteria:

1. Taste
2. Temperature
3. Crispiness
4. Saltiness

We took the leftovers home. PSA: baking fries to reheat them is a bad idea; they dry out too much.

Serving sizes vary somewhat across chains. The graph below shows the stated calorie count for a small fries at each restaurant. I got this information from the website of each chain. McDonalds offers a smaller "small" than the other chains. In-n-Out has only one size.

Potatoes contain essentially no fat, so all the fat in fries comes from the oil they are fried in.  Oil contributes about 40% of the calories in fries. Chick-fil-A has the highest stated fat (oil) content at 53%, and In-n-Out the lowest at 36%. 

Most fries are sold as part of a bundle with a chicken sandwich or a burger. If you buy them a la carte, then you'll pay a remarkably similar price of 2.5c per gram at four of the chains. KFC has more expensive fries and In-n-Out has cheaper fires. 

Burger King was the clear winner, followed closely by McDonalds. Jack in the Box was solid. Our opinions diverged on Chick-fil-A and In-n-Out, and KFC was a disappointment. 

Here are our impressions, in the order that we visited the restaurants.

KFC. This was hugely disappointing for us. When we did our chicken sandwich taste-off, we also tasted fries, and KFC was our favorite. Then, they were crisp and hot, and had the most tasty seasoning. These were dry, lukewarm, and a little soggy. It's possible the fries were less true to KFC because this was a KFC-A&W combo restaurant. We thought about stopping at another KFC on our way home, but by then we were feeling done with fries.

Jack in the Box. "No-one orders the regular fries at Jack in the Box" said my daughter as we approached restaurant number two. Jack in the Box is known for curly fries, but their regular fries were quite good. They were steaming hot and crispy, cut thinner than Burger King, but thicker than McDonalds. (We did also order some curly fries, and they were good, if a little greasy.)

McDonalds. Excellent. Crispy, hot, and tasty. Yes, I know I just parroted back our criteria. I would be interested to do a blind taste test, as I think I could identify McDonalds fries easily. They have a distinctive taste and texture that never disappoints.

Chick-fil-A. These are cut into a waffle shape rather than strips. They were not crispy and needed more salt. My daughter liked them (she's biased, lol), but I was not impressed.

In-n-Out. OK, now my turn to display some bias. In-n-Out fries are made from fresh potatoes, not frozen like the other chains. Look carefully, and you'll see them chopping the fries in store. This means they don't have a fancy coating to make them extra crispy, and they taste like potatoes. Your order always includes salt packets to salt the fries yourself; they will taste under-salted if you don't add any salt. I like them. The internet, as a whole, does not.

Burger King. Wow. Cut thicker than McDonalds, they have a thicker crispy outer layer and also more potato taste. They were perfect --- hot, crisp, and just the right amount of salt. 

Maybe next time we'll do the fancy chains like Shake Shack and Five Guys.

You can generate the figures in this article using this R code.

Addendum: In case you're curious, here are the ratings for the three chains we rated in both 2021 and 2023. We had a better experience at McDonalds this time and a much worse experience at KFC.