By Jenny Splitter

“Eat real food” is simple-seeming dietary advice thats actually anything but.2 On the one hand， it sounds easy enough： Its a guideline that appears to leave room for most food groups.3 On the other hand， though， “real food” is a slippery4 concept， one without any single established definition. And without a universal understanding of what the term describes， many people just use “real food” to mean the opposite of“processed food”—a dichotomy that doesnt do anybody any favors.5

Thats because most of us dont have a clear understanding of what “processed food” means， either. Many foods we like to think of as “whole” and “natural” undergo a fair amount of processing. As food scientist Robert Shewfelt explains， baby carrots have to be de-leaved， washed， disinfected with chlorine， chilled， cut， peeled，6 and polished prior to bagging. Bagged salads are shredded7 and triple washed， also with chlorine. Most milk in the U.S. is fortified， homogenized， and pasteurized， and thats a good thing， as pasteurization greatly reduces the risk of foodborne illness.8 Some crops， like leafy greens， are more susceptible to pathogens，9 and processing helps get them clean. Freezing， a form of processing， can preserve nutrients， whereas fresh fruits and vegetables begin to lose those nutrients under all sorts of conditions， including exposure to heat， rough handling， and refrigeration.10

And while “processed food” may sound like a modernday invention， nothing could be farther from the truth.11 The history of processed food actually begins 1.8 million years ago， when our ancestors began roasting meat； two later examples are bread and beer.

Katherine Pett， a registered dietician， finds the term“processed food” far too nebulous.12 “Various experts who promote different ways of eating or their own food products [all] have different definitions of what constitutes processed food，” she says. The category definitely includes chips， crackers， and cookies， but it also includes things like canned tomatoes， dried pasta， and hummus.13

In his book In Defense of Processed Food， Robert Shewfelt defines processed food as “a product that has been modified to improve its safety， extend the shelf life， enhance its quality， and improve its convenience.”14 Processing can also open up our diets to healthy foods that might otherwise be too time-consuming or difficult to make： Beans， for example， require overnight soaking and hours of cooking， unless theyre the canned， processed kind you find on grocery-store shelves （as Pett explains， “buying a can of beans is a good and easy way to introduce beneficial legumes”）.15 The advent of bagged lettuce，16 meanwhile， likely led to an increase in our consumption of healthy leafy greens.

Unprocessed food， then， isnt necessarily better. And as food historian Rachel Laudan notes in her essay “A Plea for Culinary Modernism，” processing can improve the flavor of healthy foods， too： “For our ancestors， natural was something quite nasty.17 Natural often tasted bad，” she writes. “Fresh meat was rank and tough， fresh milk warm and unmistakably a bodily excretion； fresh fruits （dates and grapes being rare exceptions outside the tropics） were inedibly sour， fresh vegetables bitter.”18

But what about the chemicals？ You might be thinking. Well， technically， everything is a chemical. And organic pop tarts and non-GMO chips arent any healthier， or less processed， than those made by Kelloggs or Lays.19 Weighing the health risk of certain ingredients， its important to remember that old maxim： The dose makes the poison.20 Most preservatives， additives， and other chemicals in our food are present only in trace amounts that arent dangerous or unhealthy.21

In part， our suspicion of processed foods is about nostalgia22， too. The newold trend of pickling and home canning， for example， doesnt make the end result any healthier just because the processing happens in your kitchen.23 And while we tend to feel better about homemade cookies and cakes， they usually arent any healthier than storebought， “processed” cookies； their advantage comes from the fact that they connect us to familial24 and cultural traditions.

Its worth noting， though， that this nostalgia isnt harmless： “While family meals of wholesome， home-cooked foods are increasingly romanticized，”as environmental historian Jennifer Bernstein wrote，“its likely that they are romanticized by those on the receiving end of those meals.” And as Shewfelt has noted， “shelf stable foods25， the development of ready-to-eat products， and use of microwave ovens dramatically decreased food preparation times which may have contributed to the entry of more women to the workforce.”

1. bad rap： 壞名聲。

2. “吃真食物”看起來(lái)只是簡(jiǎn)單的飲食建議，但實(shí)則不然。dietary： 飲食的；anything but： 絕不是，毫不。

3. 一方面，這一建議聽(tīng)起來(lái)簡(jiǎn)單易行，因?yàn)樗坪踅o大多數(shù)食物都留有余地。

4. slippery： 不明確的。

5. 對(duì)于“真正的食物”沒(méi)有一個(gè)統(tǒng)一的理解，人們就用它來(lái)指稱(chēng)加工食品以外的食物——然而，這一二分法卻沒(méi)有起到任何作用。dichotomy：二分法。

6. de-leaf： 脫葉；disinfect： 消毒；chlorine： 氯；chill： 冷凍，冷藏；peel：去皮。

7. shred： 切碎。

8. fortify： 加入維生素、礦物質(zhì)等以提高食品的營(yíng)養(yǎng)價(jià)值；homogenize：使牛奶中的油脂粒均勻分布；pasteurize：用巴氏消毒法對(duì)牛奶、啤酒等消毒滅菌；pasteurization： 巴氏消毒法，在某一控制溫度下給液體食物或飲料加熱以提高保藏質(zhì)量，殺死有害的微生物；foodborne illness： 食源性疾病。

9. leafy greens： 綠葉菜；susceptible： 易受感染的；pathogen： 病原體，病菌。

10. nutrient： 營(yíng)養(yǎng)物質(zhì)；refrigeration： 冷藏。

11. 盡管“加工食品”聽(tīng)起來(lái)像是現(xiàn)代的發(fā)明，真相卻遠(yuǎn)非如此。

12. dietician： 營(yíng)養(yǎng)師；nebulous： 含糊的。

13. cracker： 薄脆餅干；canned tomatoes： 罐裝番茄；hummus：鷹嘴豆泥，把鷹嘴豆搗碎后加麻油、大蒜、歐芹等配制成的冷食，為中東等國(guó)家的開(kāi)胃食品。

14. In Defense of Processed Food ：《為加工食品辯護(hù)》，在本書(shū)中，作者將加工食品定義為“那些經(jīng)過(guò)加工改造，改善其安全性，延長(zhǎng)保質(zhì)期，提升便捷性的產(chǎn)品”；shelf life： 保質(zhì)期。

15. 食品加工也讓我們能吃到更多健康食物，因?yàn)槿绻唤?jīng)過(guò)加工的話，這些食物烹飪起來(lái)費(fèi)時(shí)又費(fèi)力。比如說(shuō)，除非是超市貨架上罐裝的、加工好的豆子，未加工的豆子要泡一整晚，再煮上幾個(gè)小時(shí)才能食用（正如佩特所說(shuō)，吃罐裝豆子能夠簡(jiǎn)單又便捷地獲取對(duì)人體有益的豆科植物）。legume： 豆類(lèi)，豆科植物。

16. advent： 出現(xiàn)；lettuce： 生菜。

17. “A Plea for Culinary Modernism”：《呼吁烹飪現(xiàn)代主義》，在本文中，作者提出對(duì)于天然和純手工食品的癡迷早已過(guò)時(shí)，我們應(yīng)該追求更高質(zhì)量的工業(yè)食品；nasty： 難吃的。

18. rank： 惡臭的；excretion： 排泄物，分泌物；date： 椰棗，海棗；inedibly： 不可食用地。

19. organic： 有機(jī)的；pop tart： 一種上面有果醬或果餡的小圓餅；GMO： 轉(zhuǎn)基因生物，全稱(chēng)genetically modified organism；Kelloggs： 美國(guó)家樂(lè)氏公司，在全世界出售各種谷類(lèi)早餐；Lays： 美國(guó)薯片品牌。

20. ingredient： 原料，成分；maxim： 準(zhǔn)則；The dose makes the poison： 劑量決定毒性。這是毒理學(xué)的重要信條，即所有物質(zhì)都有一定毒性，必須基于使用的劑量來(lái)討論才有意義。

21. preservative： 防腐劑；additive： 添加劑；trace amount： 痕量，微量，指化學(xué)上極微小的量，微小到只有一點(diǎn)兒痕跡。

22. nostalgia： 懷舊。

23. 比如說(shuō)，當(dāng)下流行但由來(lái)已久的食物腌制和罐頭自制，不會(huì)因?yàn)槭窃谧约覐N房里加工的而就更加健康。pickle：腌制；home canning： 家庭自制罐頭。

24. familial： 家庭的。

25. shelf stable food： 耐貯存食品。