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  • Ever counted calories using nutritional labels?

    計算過食品標示上的卡路里嗎?

  • But just how accurate are they anyway?

    但它們到底多準確呢?

  • Hey, guys, Julia here for DNews.

    大家好,我是 DNews 的 Julia。

  • Food labels are great.

    食品標示很棒。

  • They give you an estimate of how many calories are in any certain food.

    它讓你吃東西時可以知道自己攝取了多少卡路里。

  • But they have a teeny bit of a flaw.

    但它們有一個小小的缺陷。

  • They fail to take into account cooking.

    它們沒有考量到食物的烹調方式。

  • So we end up with a system that likely overestimates the calories available in unprocessed foods and underestimates the calories in processed food.

    所以這讓我們總是高估未加工食物的卡路里量,且低估加工食品的卡路里量。

  • The way we currently count calories is based on the Atwater System, which is at least a hundred years old.

    我們目前是基於「艾特瓦特系統」去計算卡路里,而它至少有 100 年的歷史了。

  • The System standardized the idea of the amount of energy available in food, 9 calories in a gram of fat or 4 calories in every gram of protein.

    這個系統訂定各種食物中成份固定量所含的能量,脂肪每克 9 大卡,蛋白質每克 4 大卡。

  • But this measures the availability of energy in food, not the digestibility.

    但理論上這只計算到食物上能量的可利用性,沒有考量到它的可消化程度。

  • A calorie is a unit of energy.

    卡路里是能量的單位。

  • It's technically the amount of energy needed to heat up a kilogram of water by 1 degree Celsius.

    理論上來說,1 大卡是使 1 公斤的水提高 1℃ 所需要的能量。

  • Our body burns calories in food through metabolizing the carbohydrates and proteins and whatnot into smaller molecules our body can use as energy.

    我們身體通過代謝來燃燒碳水化合物和蛋白質等物質所含的卡路里,並把它們轉變成更小的分子讓我們的身體可以作為能量使用。

  • Cooking food changes how many calories are digestible.

    而食物的烹調方式會影響它的可消化性。

  • Take potatoes for example.

    拿馬鈴薯舉例。

  • When raw, the sugar molecules in potatoes are too tightly packed for our digestive system to handle.

    當生吃時,馬鈴薯的醣分子因為太緊密連結的關係,使得我們很難去消化。

  • Cooking causes the starches in the potato to gelatinize.

    而經烹調後會使馬鈴薯中的澱粉變為膠狀。

  • That process allows us to access the sugars stored in the starch, so we get more calories out of the cooked potato.

    這道程序會讓我們更能去吸收澱粉裡的醣分子,所以當我們在吃煮過的馬鈴薯時攝取的卡路里也較高。

  • On top of that, the type of cooking method might change the chemistry of food as well, whether it's boiled, baked, or microwaved.

    除此之外,烹調的方法還可能去改變食物中的分子結構,無論是用煮的、用烤的或是用微波的。

  • On the other hand, digesting raw food takes work: A stick of celery might have 10 calories, but the chewing and digesting burns about half of them.

    另外,消化生食時會需要額外的能量,像是一根芹菜裡可能有 10 卡路里,但在嚼它和消化它的過程中可能就先消耗掉 5 卡路里了。

  • All that work means there are fewer calories for your body to absorb for energy.

    這代表在吃這些生食時,我們會吸收到較少的卡路里。

  • But before you go nibbling on an all-carrot diet, consider this:

    但如果你因為這樣就只想去吃一堆生紅蘿蔔,你應該考慮一下:

  • For our ancestors, cooking meant the difference between life and death.

    對我們的祖先來說,烹調食物意味著生與死的差別。

  • The invention of a cooked meal might have changed everything.

    「烹調」這個發明可以說是改變了一切。

  • Cooking food provided more energy and led to humans with bigger brains and bigger babies.

    食物經過烹調可以提供更多的能量,使人類演化出更健全的大腦,更健康的嬰兒。

  • And people who consume an all-raw diet now might not be getting enough calories, even when eating food packed with nutrients.

    而如果有人現在只吃生食,就算那些食物都非常有營養,也還是有可能攝取不到足夠的熱量。

  • Some women on an all-raw diet get irregular menstrual cycles—a sign of undernourishmentnot to mention the bacteria of your gut steal a few of the calories for themselves.

    有些婦女也在吃全生食的過程中出現亂經、營養不良等症狀,更不用說你吃進去的細菌在你腸道裡自己偷偷消化了多少卡路里。

  • So the exact number of calories you're getting is affected by way too many factors for those labels to be truly accurate.

    所以有太多可能的因素會去導致你實際吸收的熱量,與標示上的熱量不太一樣。

  • But while modifications to the Atwater system have improved it some over the years, there's still no real alternative.

    雖然經過改良艾特沃系統後這情況有稍微得到改善,但我們還是沒有什麼其他計算熱量的選擇。

  • So until nutrition scientists come up with a better calorie counting system, take food labels with a grain of salt.

    因此,除非營養科學家們想出了一個更好的卡路里計算系統,食物標示參考參考就好啦。

  • See what I did there? Grain of salt? It's a... pun... ok.

    看我做了什麼?一撮鹽 / 持保留態度?這是...雙關語...

  • Switching gears for a second, I wanted to let you know that tomorrow, Trace, Amy, and Ian are gonna be chatting with a real-live astronaut about what it's like to live and work in space.

    題外話一下, 我想跟你們說,就在明天 Trace、Amy 跟 Ian 就要訪談一位太空人,聊聊真正在太空中工作和生活是什麼感覺。

  • And if you wanna hang out with us space nerds, be sure to RSVP using the link we've got in the description.

    如果你也想一起加入的話,請利用以下連結回覆給我們。

  • That's at 3 p.m. Eastern time, noon Pacific.

    時間訂在東部時間下午三點,中午太平洋時間。

  • So, do you trust nutritional labels?

    所以你現在還相信食物標示嗎?

  • Do they need to be updated?

    你覺得它們應該要更新一下嗎?

  • Leave your thoughts and comments below, and don't forget to subscribe for more DNews everyday.

    請在下面留下您的想法和評論,還有別忘記訂閱我們的頻道鎖定更多每日快訊。

Ever counted calories using nutritional labels?

計算過食品標示上的卡路里嗎?

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