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Stephen DUBNER: So what does it say, Kenji, that there are so many conventional wisdoms about something as basic as cooking food, which we’ve been doing for thousands of years, that are, if not wrong, at least kind of misguided? Isn’t that sort of strange?

J. Kenji LÓPEZ-ALT: It is strange. But I think it’s precisely because we’ve been doing it for so long and because everybody does it and it’s sort of an essential part of everyday life that I think it’s one of those things that rarely gets a sort of a second thought.

Today we’re going to give a lot of second thoughts — to what we eat and how we eat it.

LÓPEZ-ALT: My name is Kenji López-Alt. I’m the managing culinary director at and I write about the science of food.

Uh-oh. “The science of food.” Doesn’t that sound kind of … unnatural?

LÓPEZ-ALT: I think a lot of people think of science as sort of the opposite of tradition or the opposite of natural. And really it’s not. Science is just a method, right? It’s a method of thinking about the world and it can be used for many different ends.

All right, then! I’m on board. How about you? Would you like to know whether the secret of New York pizza really is the water? Would you like to know how Freakonomics Radio listeners do things in the kitchen? And would you like to know the true nutritional value of one of America’s favorite vegetables?

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His full name is J. Kenji López-Alt. The “J.” is for James, his given first name. He’s always gone by Kenji but he didn’t want to totally lose the “James.” “Alt” is his last name; his father is of German descent. His mother is Japanese — that’s where the “Kenji” comes from. And the “López” is the last name of Kenji’s wife — she’s Colombian. When she and Kenji got married, they both became “López-Alt.”

J. Kenji López-Alt has just published a big, beautiful doorstop of a book.

LÓPEZ-ALT: It’s almost 1,000 pages, it’s pretty big.

It’s called The Food Lab: Better Home Cooking Through Science. The first line: “I was never meant to be a food guy.”

LÓPEZ-ALT: I came from a family of scientists. My father is a microbiologist and my grandfather is an organic chemist. I had a very science- and math-heavy childhood. I was one of those kids that would wake up at 6:30 in the morning to go and watch Mr. Wizard on Nickelodeon. Still one of my favorite shows. And honestly, I think, on a conceptual level, everything I learned about basic science all the way through college I learned from  that show.

DUBNER: Really? You’re not joking?

LÓPEZ-ALT: I’m not joking. I’m not joking.

DUBNER: So you were way into science as a kid. Were you into food as a kid?

LÓPEZ-ALT: No. I mean, my family liked eating, but I was one of those kids who, you know, I hated fish until I was probably in my early 20s. When I went to college, I had no idea how to cook.

DUBNER: What would be a typical family Sunday night meal, let’s say?

LÓPEZ-ALT: Well, my mom is Japanese. She moved to the U.S. when she was a teenager. And so, her food is — she did all of the cooking at home for the most part. My dad would occasionally cook a special meal, you know, when he felt like cooking. He would cook a lot of Mexican or Chinese food, and those were always nice nights. But my mom cooked our daily food. It was always sort of a mix between Japanese food and Betty Crocker 1970s staples.

A lot of the recipes in The Food Lab nod toward those ’70s staples — but are improved upon, through science.

DUBNER: OK, so I’m about to make an assumption. Tell me if the assumption is right or totally wrong. As a kid, you were science-obsessed. You went to M.I.T. and at the beginning, studied biology. You come from a family of scientists. So, my assumption is that all of that got kind of baked into you to some degree, this kind of appreciation for — at least familiarity with — the scientific method. And then, when you fell in love with food and cooking, you naturally kind of parlayed the scientific method into the cooking method. Is that at all true? Or not?

LÓPEZ-ALT: Yeah, that’s very accurate. Remarkably accurate. I found, when I was working in restaurants, that I did have this sort of natural curiosity about why things work.

He first found his way into the kitchen during college. It happened by accident and also — important life lesson here — by lying.

LÓPEZ-ALT: The summer after my sophomore year, I decided I wanted to take the summer off from any kind of academic work because I was kind of getting burned out on biology. So I decided to go get a job as a waiter. I walked around Boston trying to find a job as a waiter and nobody wanted to hire me. And then, one of the restaurants I walked in to, they said they didn’t have any waiter positions available, but one of their prep cooks didn’t show up that morning and if I could hold the knife then I could have a job as a cook. And so, I lied and I said, “Yeah, I know how to use a knife.” And literally, I don’t think I’d ever cut anything with a chef’s knife in my life before.

He was hooked.

LÓPEZ-ALT: So, yeah, from the moment I stepped into the kitchen, I was like, this is the life for me. This is great.

He did graduate from M.I.T.

LÓPEZ-ALT: I switched majors to architecture. So I finished with a degree in architecture, structural engineering.

But then he spent the next eight years working in a bunch of different Boston restaurants. But as López-Alt writes in The Food Lab, “I discovered that in many cases — even in the best restaurants in the world — the methods that traditional cooking knowledge teaches us are not only outdated but occasionally flat-out wrong.” This was, of course, his science background talking.

LÓPEZ-ALT: You know, why are we cooking it this way? Would it be better to cook it this way? And that’s something that is actually not very easy to work with when you’re in a restaurant because it’s such a fast-paced  environment; you don’t really have time to ask those questions or investigate them or answer them. That was also one of the reasons why I felt this desire to get out of restaurants and go into writing because I thought it would give me more time to actually think about these things and answer these questions that have been building up for so many years.

His first writing job was at Cook’s Illustrated magazine.

LÓPEZ-ALT: So, they have a big kitchen in Brookline, Massachusetts. It has like 30 ovens, 25 burners; it’s a big test kitchen. And that was pretty much perfect for me because they sell magazines by asking questions and spending the money and the time to answer them.

First at Cook’s Illustrated and later at Serious Eats, López-Alt began to refine a methodology:

LÓPEZ-ALT: The first step is always research. So, what I’ll do is I’ll go look to as many sources I can for the history of the dish, as many different recipes to see how different people are making it.

Then he starts to reinvent a recipe, or at least rethink it.

LÓPEZ-ALT: I try and find areas where I think there might be problems for home cooks or areas where I think it can be improved in efficiency.

Often this means taking a step backward — not thinking just in terms of ingredients and texture and flavor but scientific basics, like temperature.

LÓPEZ-ALT: There’s a difference between temperature and energy. And that’s a concept that I think a lot of people have a difficult time wrapping their heads around. But the really quick and easy way to demonstrate it is, if you think about a pot of water that’s boiling, the temperature of that water is 212 degrees Fahrenheit, 100 degrees Celsius. And if you stick your hand in there, you’re going to burn your hand. At the same time, you can have an oven at 212 degrees Fahrenheit or 100 degrees Celsius and you can stick your hand in there for like a minute and you’ll barely feel it. It can feel hot, but you’re not going to burn yourself. And the way this could bear itself out in cooking is, for instance, if you’ve been used to cooking your pizzas on a baking stone, which a lot of people have in their ovens, a stone is not particularly dense compared to, let’s say, solid metal. There are now things we call baking steels, which are solid sheets of steel that you heat up in your oven and they transfer energy to your pizza much, much faster than a stone can, even if they’re at the same temperature. So, you can have a steel at 450 degrees and a stone at like 550 degrees and the pizza that’s placed on the steel will  actually cook faster than the one that’s placed on the stone.

DUBNER: Tell me something I don’t know about the geometry of food. You refer to that a few times in your book. Why is that important? How should I think about it differently?

LÓPEZ-ALT: The geometry of food is important because one of the big things is surface-area-to-volume ratio.


LÓPEZ-ALT:  I like to think about it this way, where if you’re looking at the edge of a piece of General Tso’s chicken. And say you’re looking at it from about two feet away. You try and trace the outline of that General Tso’s chicken and you say, “All right, the perimeter of that piece of chicken is two inches.” And then you look at it a little bit closer and you see, you know what, I was just tracing a very rough outline. If I actually go in and fill in these little crags, now it’s more like two-and-a-quarter inches. And if you look even closer, you’ll see that maybe it’s more like two-and-a-half inches. And this is a phenomenon that geologists see with coastlines — that the further away you are, the smoother they seem and the shorter they are. But it’s important, because with a food like fried chicken you want it to be really, really crisp. And the more surface area you have, the more sort of little nooks and crannies you have, the crisper it’s going to feel in your mouth, the better sauce is going to cling to it. All those things. So crispy foods, you want them to be really craggly and have a very high surface-area-to-volume ratio.

DUBNER: Is there any instance — I’m sure there are — where more surface area is not better?

LÓPEZ-ALT: Yeah. If you want to, say, cook a prime rib roast for example, or even like a tenderloin steak that you want it to actually be in as compact, either as spherical or cylindrical shape as possible because that minimizes surface-area-to-volume ratio and that’s important because for things like that, the more surface area you have, the more it’s going to dry out while it’s cooking because there’s just more surface for moisture to escape from and the less evenly it’s going to cook. So that’s why, if you’re cooking a tenderloin steak or you’re roasting a whole tenderloin or prime rib, you generally want to tie it up a little bit so that it retains that nice cylindrical shape. And that, you know, it’s about more than just aesthetics. It actually reduces the surface area and thus keeps it, helps it retain juices and cook more evenly and better.

The underlying component of the Food Lab methodology is the same underlying component of most bench-science: experimentation.

LÓPEZ-ALT: For something like General Tso’s, for example, my big goal from the very beginning was to get the chicken to be as crusty and craggly as possible and to make sure that it developed a crust that would stay crispy even after you tossed it in this sort of gloopy sauce. So a lot of my testing for that recipe was with various types of breading and frying methods and how to really enhance that crispness.

DUBNER: Can you name a few of each — the breading and methods?

LÓPEZ-ALT: If you want to start with basics,  I tried dipping it in cornstarch. I tried dipping it in a cornstarch slurry followed by dried cornstarch. I tried using various mixes of cornstarch and wheat  flour. I tried potato starch. I tried tapioca starch. I tried doing sort of a southern style, like brining the chicken in Asian flavors with a little bit of buttermilk to tenderize it. I tried using eggs versus no eggs — many different things like that. The final recipe I ended up with uses some vodka in the batter, which is—

DUBNER: You’re fond of vodka for battering, yes?

LÓPEZ-ALT: I am. I use it in a few different things. Usually you use it when you want to develop crispness but also maintain the lightness, because vodka will help moisten a batter or a dough but it doesn’t develop gluten the way that water does, so it stays nice and light and doesn’t get tough. And the other thing that vodka does is it evaporates much faster than water does. It’s more volatile than water so when you put food that’s been dipped into a batter made with vodka into hot oil, that vodka really violently bubbles away very quickly. So that sort of lightens up the coating and it makes it much crisper.

DUBNER: Gotcha. So which of those coatings ended up winning?

LÓPEZ-ALT: I believe I did a mixture of vodka, corn starch and a little bit of wheat flour along with some soy sauce. So, the chicken gets dipped in that wet batter and then tossed in a dry starch mixture.

DUBNER: I’m just curious how, I guess, rigorous your experiments are. Would they pass muster in a science lab, for instance?

LÓPEZ-ALT: Sometimes. If there’s really a sort of deep question about cooking that people are very conflicted on, then I will actually do a really well-controlled experiment — double blind. So, for example, one of the ones I did a number of years ago was to answer the question whether New York pizza is really good because of the water. And people say it is. And you know, people use it as an excuse, a lot, for why they can’t make good pizza outside of New York. So for that one, actually, I did a full double-blind experiment where I got water — starting with perfectly distilled water and up to various levels of dissolved solids inside the water.

DUBNER: And New York has a high level, I assume, of dissolved solids?

LÓPEZ-ALT: Pretty high, yeah. Not the highest, but pretty high. So, I think I had six different water samples, ranging from very high to nothing, and I put them into numbered bottles and then I had an assistant — my wife — rearrange the numbers on the bottles. And then I passed the bottles onto a pizza chef in New York. So, I didn’t know what was in the numbered bottles. He didn’t know what was in the numbered bottles. I also doubled a couple of them up as a control to make sure that our testing panel was on point. And then I had a bunch of people — a mix of sort of amateurs and also sort of professional food writers — come and taste the pizzas blind. What we basically ended up finding was the water makes almost no difference compared to other variables in the dough. And yeah, that one, it’s a sort of silly premise. But it was a rigorously controlled test.   

DUBNER: Hey, as someone who lives in New York and eats pizza, I don’t think it’s a silly premise at all. I think that’s exactly what science is for.

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DUBNER: It strikes me that everything we’re talking about, so far, is geared toward cooking for taste. Which makes perfect sense, because eating is incredibly pleasurable, in addition to being necessary. But then there’s a school of thought, small but growing, that says that one reason we’ve gotten into such nutritional trouble  is because we have had the luxury to eat for taste and that we stopped eating for nutrition. I’m just curious what your thoughts are there, because  your book is unapologetically about deliciousness. And when you write about making these super-creamy, cheesy au gratin potatoes, it’s like we’re going — it’s full monty. It’s as much cream as we can, as much butter as we can. And I love your celebration of that. On the other hand, you are doing this in an era when there’s a lot more focus on nutrition. I’m just curious how you balance that?

LÓPEZ-ALT: Well,  I’m one of these people who really thinks that it’s all about moderation. And from the way my book is written, you might think that I eat steak and potatoes every night, but the reality is actually really far from that. So, if I’m going to eat a hamburger, I want that to be the best damn hamburger I can make, right? So that’s where this idea that I’m going to try to perfect these foods, these comfort classics that people love — that you shouldn’t necessarily eat every day, but when you make them you want them to be really great. So, on a day-to-day basis, my wife and I stay mostly vegetarian; we eat a lot of fish, a lot of seafood. We both exercise. So,  you know, food can be delicious, but  it should also be sustaining at the end, and your health is not really worth that extra serving of burgers or extra serving of creamy potato casserole.

Coming up after the break: we go deeper into the delicious-versus-nutritious debate. Even a lot of the fruits and vegetables we eat are not very good for us. But first, a couple more kitchen tricks. Here’s Kenji LÓPEZ-ALT on scrambled eggs:

LÓPEZ-ALT: The one big thing with scrambled eggs, if you really want to improve them and you have a little bit of extra time in the morning, is if you salt your eggs while they’re raw, you know, a pinch of salt in the eggs while they’re raw, beat them up and let them sit for about 15 minutes, they’ll actually retain moisture a lot better than if you were to just cook them straight and salt them at the beginning.

He can also help out with your pie crust.

LÓPEZ-ALT:  If you use vodka in place of some of the water in your pie crust, it doesn’t make the pie boozy, but you end up with a dough that is much flakier and much lighter.

We also asked Freakonomics Radio listeners to tell us their kitchen tricks and hacks and superstitions.

JANE: Hi, my name is Jane, I’m 25 years old. I currently live in New York but I grew up in Taiwan. A culinary trick I learned growing up was that when boiling an egg, you can tell whether or not it’s fully cooked by trying to pick it up with chopsticks.

JOEL: Hi, my name is Joel from Melbourne, Australia. I’ve been told by my mom when preparing cucumbers, to cut off both ends of it and to rub it on the previously cut part and it will somehow remove the bitterness.

TIFFANY: Hi, this is Tiffany in Cupertino, California. My baking tip is that contrary to what Martha Stewart always said, you do not need to mix your salt and your baking soda into your flour in a separate bowl before you add it to the rest of your batter.

DAVID: This is David Lyons out of Denver, Colorado. And the culinary secret I learned from my wife, who is Korean, is to always soak rice before you cook it.  Once you start doing this way, there is no going back.

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Not much is known about when humans began to cook food — although cooking is widely thought to have started long before agriculture. The earliest archaeological evidence of humans’ controlling fire — and possibly cooking — dates to roughly a million years ago. But the Harvard anthropologist Richard Wrangham argues that it started nearly a million years before that. He also argues that cooking is what made us human — that it allowed our prehistoric ancestors to spend less time and energy chewing raw foods; and that that energy could be directed toward growing the human brain. But that’s not the only reason to appreciate cooking. It releases nutrients in raw foods and often makes them more potent and easier to digest.

Jo ROBINSON: There are some foods — and kale and broccoli are two of them — that we absorb more of their cancer-fighting ingredients if we eat them raw. But most fruits and vegetables benefit from light cooking, either a sauté maybe in olive oil at low temperature or lightly steamed — less cooked than most people cook them. But the light steaming or gentle sauté breaks down cell walls, which makes more of the nutrients available to us. So, we’ll get three or four times more nutrients from a cooked carrot than from a raw one.

Let me introduce you to someone:

ROBINSON: My name is Jo Robinson and I’m an investigative journalist.

And she’s spent most of her career studying nutrition and food.  Unlike Kenji López-Alt, Jo Robinson was destined for her career path.

ROBINSON: It really came down to this amazing grandmother that I had who had a sense about food and wholesomeness, in 1910. She and a group of women were critical of the Agricultural Department for saying that we should be eating white bread instead of whole-wheat bread. And the thinking of the time — this was the food science of the time — was that all of that fiber and the bran and the germ were just roughage that we couldn’t digest well so it wasn’t good for us.  And this group also lobbied that Coca-Cola should not be sold.

Her grandmother very much influenced the way the family ate.

ROBINSON: So, more than other kids, we had whole grain. We ate nuts and seeds and brewer’s yeast and lots of fruits and vegetables. So, I just grew up with that as being normal.

As a kid, growing up Washington state — partly in Tacoma and partly in the Puget Sound wilderness — Jo Robinson would sometimes spend her allowance on Wonder Bread so she wasn’t the only one in school with a sandwich on homemade wheat bread. As an adult, she tries to sort out nutritional myths from reality.

ROBINSON: My job is to go into the scientific journals, find what I think is important for human health, and repackage it in a way that people can  first of all understand its importance, and then find, “what am I gonna pick in this grocery store? What am I going to pick in this farmer’s market?” So really it takes someone like myself to translate science into action steps.

Robinson’s latest book is called Eating on the Wild Side. It’s fascinating. Almost every page tells you something you don’t know about food, especially fruits and veg and herbs. And a lot of it goes back to that split between delicious and nutritious.

ROBINSON: Well, we humans are programmed, and have always been programmed, to prefer food that is high in carbohydrates, starches and sugar, and oil, because those kinds of nutrients were very poor in the wilderness. And we had to be motivated with these feel-good brain chemicals to go out and get them. And so, over time we just kept picking sweeter, fatter, richer, softer, less fibrous food, never knowing what we’re doing. And only now do we have the technology and the slowly accumulating wisdom to know how we should transform our food supply to make it optimum for human health.

In Robinson’s view, America has been guiltier than others.

ROBINSON: I don’t think Americans are stupid when it comes to food, nutrition and health. But what happened is all of these great food cultures of the countries that we came from got lost when we came here. And everything became homogenized. And then we became leaders in industrial agriculture, which has nothing to do with nutrition; it has to do with volume and with flavor.  So  the vast majority of food crops in this country, we’re growing them because they’re highly productive or disease-resistant. Those are the two criteria that farmers use, and agricultural schools use, to determine what varieties we’re going to eat. They’re not looking at food value.  So, other countries throughout the world tend to have more nutritious diets than we do. And then, we started breeding out all signs of bitterness because food manufacturers knew that about 25 percent of the population does not like bitter foods, in even low amounts. So, they’re not going to create something that 25 percent of their potential sellers are going to avoid. Just this taking away the bitterness took away a lot of the antioxidants.  All of those trends continued. So, we have a very bland, low-antioxidant, soft diet.

Consider, for instance, one of the most popular vegetables in America.

ROBINSON: Overwhelmingly, people in this country eat iceberg lettuce. In fact half the people in this country have never eaten anything other than iceberg lettuce.

Now, let me clarify. Not that half the people have never eaten anything other than iceberg lettuce — but no other lettuce. Now, why is that?

ROBINSON: It’s a very productive lettuce — many, many tons of lettuce per acre. And it’s also a very mild-tasting lettuce and as a culture, we are pretty bitter-adverse. So, we like the fact that iceberg lettuce has kind of a watery crunch and doesn’t have a lot of flavor.  So it’s everywhere.

OK, so maybe iceberg isn’t one of those classy salad greens — arugula or mizuna or even just a romaine. But hey, it’s still a vegetable, right? Which means it’s still got a lot of nutritional value, right?

ROBINSON: Iceberg lettuce has fewer nutrients than any other lettuce in the store. In  fact, veterinarians don’t even recommend it as rabbit food because there’s not enough nutrients to support the health of rabbits.

To think productively about our nutritional present and future, Robinson began by looking to the past.

ROBINSON: I began to compare the food that we’re eating today with the wild diet that sustained us for about 98 percent of our evolution.  And it was so very clear that over time we have greatly diminished the nutrient content of our animal products and everything that we grow. For example, the antioxidant content of wild plants varies to 2-400x greater than the domesticated counterparts that we eat today.

Robinson believes, powerfully, in the value of antioxidants.

ROBINSON: Well the word “antioxidant” can tell a lot of the story. It’s against oxidation. And oxidation is just this chemical process where a molecule grabs an electron from another molecule , which sets up this chain reaction which can cause all kinds of destruction in every cell in our body.

As Robinson writes, “Plants can’t fight their enemies or hide from them so they protect themselves by producing an arsenal of chemical compounds that protect them” — from insects, disease, harsh weather, and sunlight. And many of those compounds function — for us, when we eat them — as antioxidants. The problem is that, as a result of many years of breeding food for taste and productivity, we’ve created a menu of modern fruits and vegetables that aren’t necessarily good for us.

ROBINSON: There are some fruits in particular that may be bad for our health. And that’s something that a lot of people just can’t believe.  But there’s this interesting study where some Italian* researchers took people — men actually, overweight men — who were at high risk for heart disease. And they decided to add a fruit a day to their diet, thinking that that would reduce their risk. And so they chose apples. You know, an apple a day keeps the doctor away. So these overweight men, prone to heart disease, divided into two groups. One continued their normal diet, one had their normal diet plus a Golden Delicious apple a day. And at the end of the study those men who were eating the Golden Delicious apple had higher levels of triglycerides, which are an independent predictor of heart disease, and the worst kind of cholesterol. And the problem with this particular variety of apple , it’s very high in fruit sugars, and it’s lower in antioxidants than many other varieties. So the health benefits in that variety are low, the sugar is high.

*Jo Robinson cited a study about the health benefits of Golden Delicious apples and mistakenly attributed it to Italian researchers. The study was conducted by Iranian researchers, not Italian researchers.

So you may think that eating any fruit or vegetable is good for you.

ROBINSON: But that’s certainly not true. Because the fruits and vegetables that most people pick in this country are extremely low in antioxidants. And that includes things like melons and sweet corn, white sweet corn and white potatoes and bananas, iceberg lettuce. They’re at the bottom of the totem pole when it comes to food values.

So what’s the solution?

ROBINSON: We need to find out what science is now telling us about the best varieties of fruits and vegetables to eat. And this is complicated science and it’s not widely adopted at this time. You’re not going to find the USDA saying, “Eat more of the cabbage family because it has glucosinolates in it” — which are cancer-fighting organisms. So, we really need to go outside of mainstream nutrition and agriculture to find what’s best for our health.

That’s the mission Jo Robinson is on. She advocates seeking out the less-sweet, less-homogenized version of whatever you’re already eating.

ROBINSON: The best thing that you can be eating in terms of true lettuces would be a red-leaf or dark green-leaf lettuce, with red-leaf lettuce far superior to the others.

A Granny Smith or Honeycrisp apple is better than a Golden Delicious — although heirloom varieties, Robinson writes, are generally much better than supermarket varieties. The very popular Russet Burbank potato has a lot of nutrients but also a very high glycemic index; on that front, red- and blue-fleshed potatoes are much better, but harder to find. And in this family of vegetables, sweet potatoes or yams, are the healthier choice. Berries are great – but, again the wilder, the better.

ROBINSON: There’s really nothing better for our health than wild berries. Wild berries tend to have from 2-10x more health-enhancing phytonutrients than our domesticated varieties.

And it’s not just choosing the better varieties of the foods we eat. It’s when we eat them.

ROBINSON: I do call this “Eat Me Now.”

“Eat me now” because why?

ROBINSON: When plants are harvested, we think that they’re dead. They’re not. They’re actually living until we eat them or cook them. And all the time they’re alive they’re burning up their own antioxidants to protect the fact that they’re still inhaling oxygen. But they’re not producing more antioxidants because you can’t do that once you’re harvested.  So you need to eat them the day you buy them or the next day, ideally. So, these are some of the things that you want to eat me now: spinach, asparagus, broccoli, artichokes, kale, green onions, mushrooms, parsley and cherries. And if you do that, you may get two, three, five, ten times more antioxidant than if you push them to the back of the refrigerator and remember or find them a week or two later.

Now, you might infer Robinson’s “eat me now” rule to also mean “eat me raw.” But she says the raw-food movement is misguided.

ROBINSON:  It’s difficult to find science to support the idea that we’re healthier eating raw produce than lightly cooked produce.

Where does the raw-food idea come from?

ROBINSON: Well, one of the claims is that if you cook things you destroy plant enzymes, and that’s true. And so, the thinking is we need these plant enzymes in order to digest our food; they’re gonna make us healthier. But plant enzymes are not created for our health. They’re for the plant’s health.

And what about canned vegetables? They must be less nutritious than fresh, right? In most cases, yes …

ROBINSON: But with tomatoes, canned tomatoes are actually better for us than a fresh, organic, locally harvested, heirloom tomato. Because the nutrient in tomatoes, which is proving to be supportive of heart-health, is called lycopene. And when lycopene is heated, it is transformed into a form that we find easier to absorb. And the best source of lycopene in the entire store is tomato paste. And you know people don’t like to hear that. How could that be? But in fact, science supports it.

In scouring the scientific literature on what we eat and how we prepare it, Jo Robinson has come up with her own list of kitchen tricks. Unlike Kenji López-Alt’s work, which is meant to optimize taste, hers is meant to optimize nutrition. Garlic, for instance. A lot of us cook with garlic for flavor but also because of its reported healing properties. But heat can destroy those properties. There is, however, a simple trick to prevent this: after crushing or chopping the garlic, let it sit for at least 10 minutes before cooking it. That allows its health-promoting compound, allicin, to form.

As for the best way to cook most vegetables if you want to optimize their nutrition?

ROBINSON:  Many people are surprised to hear that steaming vegetables in the microwave is probably the best way to preserve nutrients. You want to destroy some of those enzymes that are getting rid of antioxidants as quickly as you can. And you want to cook the food for as short amount a time as possible. So, the microwave will do that for you. You just put it in a microwave steamer and cook it for just a couple of minutes and it’s done

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LÓPEZ-ALT: if you’re happy with the way you’re cooking and you’re happy with the food, then there’s no real need to change it.

That’s Kenji López-Alt again.

LÓPEZ-ALT: But, if you could make your food slightly better or more efficient or taste better by  doing something a little bit different and someone else is willing to go and do the work to figure out what that different thing is, then I don’t see a reason why you wouldn’t want to change it.

In this regard, López-Alt and Jo Robinson are in precisely the same camp: using science to improve what we eat and how we eat it, wherever you fall on the spectrum of delicious versus nutritious. Presumably we’re all looking for some sane balance of the two. If you think about it, food is probably the single most important input that we control in terms of helping our bodies and minds function. So of course we should try to optimize its contribution to that end. On the other hand, life is short. And eating is a delight.

LÓPEZ-ALT: I have a very, sort of, “deliciousness first” approach to it.  If I’m going to eat a hamburger, I want it to be the best damn hamburger I can make.

OK, so how does Kenji López-Alt make the best damn hamburger? Well, he’s actually got a variety of burger recipes in his book. But the recipe, as with anything, is the easy part. The hard part is getting the science right. In this case, it begins with the salt.

LÓPEZ-ALT: So, what salt does when it interacts with meat is it’ll initially pull out liquid from the meat through osmosis, which we all learned in middle school science. It will pull out liquid and then that salt will sort of dissolve in that liquid,  and then what happens is it forms a kind of super-concentrated brine. And that brine will actually dissolve some of the muscle proteins, particularly a protein called myosin. This can affect meat in a couple of ways. So, particularly with ground meat, if you salt your ground meat, and you work the salt into it, it’ll dissolve this protein myosin. And then, once that protein is dissolved, it’ll cross-link to form a protein network that makes the meat sort of tighter and helps it retain moisture better. But at the same time it really drastically alters the texture. Any sausage maker will actually know this, that you’ll salt your meat probably a day in advance. Then, the next day, you’ll grind it and knead it all together like you’re making dough. And in fact, it is very much like you’re making dough, because you’re creating this sort of protein network that traps everything else in. And that’s what gives a sausage a sort of nice, springy, bouncy juicy texture. But, on the other hand, if you were to do this to hamburgers, you end up with burgers that are tough and rubbery. For a hamburger, I would recommend only salting the very outside of the burger after you’ve formed it. And actually, recently my colleague and I, we made a series of videos. And as part of one of these videos, we were talking about burgers — about this very effect — and we rented a baseball pitching machine that would throw hamburgers at the wall at 45 miles per hour. And you know, we tried it with two identical patties, one of them salted on the inside, one salted only on the outside. And we shot the whole thing in slow-motion. And you’ll see that salted hamburger kind of bounces off the wall like a rubber ball. It cracks a little bit, but it basically just bounces off, whereas the burger that has salt only on the outside kind of splatters. And you know, it’s something that you can  very easily taste in your mouth. A burger made with salted meat will be tough and one made with salt only on the outside will be tender and juicy, which is the way I want my burger to be.

DUBNER: I really want your job, I have to say.

LÓPEZ-ALT: It’s a pretty great job.

*     *    *

Freakonomics Radio is produced by WNYC and Dubner Productions. This episode was produced by Arwa Gunja. Our staff also includes Christopher Werth, Greg RosalskyJay CowitMerritt JacobKasia Mychajlowycz, Caroline English and Alison HockenberryIf you want even more Freakonomics, you can also find us on Twitter, Facebook and don’t forget, subscribe to this podcast on iTunes or wherever else you get your free, weekly podcasts.

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  • Watch J. Kenji López-Alt and journalist Katie Quinn put the scientific principles behind his cooking to the test.