What is a calorie? - Emma Bryce

Translator: Matthew Brave Reviewer: Alan Watson

We hear about calories all the time.

我哋成日聽到「卡路里」

一塊餅乾有幾多卡路里？

How many calories are in this cookie?

How many are burned by 100 jumping jacks,

100 次「星星跳」可以消耗 幾多卡路里？

or long distance running,

長跑又消耗幾多呢？

or fidgeting?

咁細嘅動作呢？

But what is a calorie, really, and how many of them do we actually need?

但係卡路里到底係咩意思？ 仲有我哋需要幾多卡路里？

Calories are a way of keeping track of the body's energy budget.

卡路里其實係我哋掌握 身體嘅能量攝取同消耗嘅一個工具

A healthy balance occurs when we put in about as much energy as we lose.

如果能量嘅攝取同消耗可以一樣 係最健康嘅狀態

If we consistently put more energy into our bodies than we burn,

如果我地攝取嘅能量多過身體所需

the excess will gradually be stored as fat in our cells,

過量嘅部分就會被轉化成脂肪 儲存喺細胞裏面

and we'll gain weight.

然後我哋體重就會增加

If we burn off more energy than we replenish, we'll lose weight.

相反，如果消耗嘅能量超過攝取量 我哋體重下降

So we have to be able to measure the energy we consume and use,

所以我哋需要計算到我哋 身體嘅能量攝取同消耗

and we do so with a unit called the calorie.

於是我哋就用卡路里呢個單位去計

One calorie, the kind we measure in food, also called a large calorie,

我哋所量度食物當中嘅 1 卡路里 亦可以叫做 1 大卡路里

is defined as the amount of energy

佢嘅定義係 1 公斤嘅水

it would take to raise the temperature of one kilogram of water

溫度升高攝氏 1 度嘅時候

by one degree Celsius.

所需要吸收嘅熱量

Everything we consume has a calorie count,

每一種食物都有一個卡路里數值

a measure of how much energy the item stores in its chemical bonds.

用黎計食物入邊嘅化學鍵嘅能量

The average pizza slice has 272 calories,

一件普通披薩有 272 卡

there are about 78 in a piece of bread,

一塊麵包大概有 78 卡

and an apple has about 52.

一個蘋果就大約 52 卡

That energy is released during digestion,

呢啲能量喺消化過程當中會被釋放出黎

and stored in other molecules

然後儲存喺其他分子當中

that can be broken down to provide energy when the body needs it.

呢啲分子可以降解 為身體需要嘅地方提供能量

It's used in three ways:

呢啲能量會喺三個情況下使用

about 10% enables digestion,

大概 10% 會用喺消化過程當中

about 20% fuels physical activity,

20% 用喺身體活動度

and the biggest chunk, around 70%,

最大嘅 70% 左右

supports the basic functions of our organs and tissues.

用黎支持器官同組織嘅基本運作

That third usage corresponds to your basal metabolic rate,

第三個用途其實就係 同我哋身體嘅基礎代謝率有關

a number of calories you would need to survive

當你唔吃飯唔郁嘅時候都好

if you weren't eating or moving around.

你都需要一啲卡路里去維持生命

如果加埋消化同身體活動

Add in some physical activity and digestion,

and you arrive at the official guidelines

你就會到達指引裏邊嘅數值

for how many calories the average person requires each day:

就係一個人一日需要幾多卡路里

2000 for women and 2500 for men.

女性 2000 卡，男性 2500 卡

呢啲估算係基於一啲因素

Those estimates are based on factors

like average weight, physical activity and muscle mass.

好似平均體重、運動量同肌肉水平

So does that mean everyone should shoot for around 2000 calories?

咁係咪每個人嘅目標都係 2000 卡？

Not necessarily.

其實唔一定

If you're doing an energy guzzling activity,

如果你做一次劇烈嘅體能活動

like cycling the Tour de France,

譬如話環法單車賽

your body could use up to 9000 calories per day.

你身體每日就會消耗最多 9000 卡

Pregnancy requires slightly more calories than usual,

比起未懷孕個陣 孕婦需要多少少嘅卡路里

and elderly people typically have a slower metabolic rate,

而老年人身體代謝率通常比較慢

energy is burned more gradually, so less is needed.

能量會消耗得比較慢 所以身體需要較少嘅卡路里

Here's something else you should know before you start counting calories.

以下亦都係一啲你開始計卡路里之前 需要知道嘅嘢

食物標籤上面標註嘅卡路里數值 係指食物中含有嘅熱量總數

The calorie counts on nutrition labels measure how much energy the food contains,

not how much energy you can actually get out of it.

唔等於你可以從中攝取嘅熱量

Fibrous foods like celery and whole wheat take more energy to digest,

芹菜同埋全麥食品呢類纖維食物 消化嘅時候需要更多嘅能量

so you'd actually wind up with less energy from a 100 calorie serving of celery

所以如果芹菜同埋薯片都含有 100 卡

食完芹菜之後會比食薯片獲得更少熱量

than a 100 calorie serving of potato chips.

唔單止噉 當一啲食物提供咗蛋白質、維他命

Not to mention the fact that some foods offer nutrients like protein and vitamins,

while others provide far less nutritional value.

其他就提供唔到咁多嘅營養

Eating too many of those foods

如果食太多低營養嘅食物

could leave you overweight and malnourished.

有可能導致體重超標或者營養不良

And even with the exact same food,

就算係兩份完全相同嘅食物

different people might not get the same number of calories.

唔同嘅人食落去都會獲得唔同嘅熱量

Variations in things like enzyme levels,

因為人體內消化酵素嘅數目

gut bacteria,

腸道細菌

and even intestine length,

甚至係腸嘅長短

都會影響人喺食物中

means that every individual's ability to extract energy from food

攝取卡路里嘅能力

is a little different.

所以，就算卡路里係有效量度熱量

So a calorie is a useful energy measure,

but to work out exactly how many of them each of us requires

但係要計每個人具體需要幾多卡

we need to factor in things like exercise,

我哋需要同時考慮唔同因素 好似運動量

food type,

食物種類

and our body's ability to process energy.

同埋我哋身體消化吸收嘅能力

Good luck finding all of that on a nutrition label.

祝你哋以後搵食物標纖嗰陣好運