How many calories are in this cookie?

常常有人會問：這餅乾有多少卡路里？

How many are burned by 100 jumping jacks, or long distance running, or fidgeting?

那跳 100 下的開合跳 (跳起來雙臂舉起，雙腿向外展開的一個動作) 、長距離跑步、或是動動身體可以燃燒多少卡路里？

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

但是，到底什麼是卡路里？而我們到底需要多少熱量？

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

卡路里是一種追蹤身體能量消耗與攝取的方式

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

當我們攝取的卡路里與我們消耗掉的相同時，身體就達到平衡

If we consistently put more energy into our bodies than we burn, the excess will gradually be stored as fat in our cells, and we'll gain weight.

但是，如果過量的熱量進入我們的身體則會變成脂肪儲存在我們的細胞 (大量儲存下會導致脂肪細胞肥大化)我們的體重因而增加

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

相對的，如果我們消耗的熱量遠遠多於所攝取的話，我們則會變瘦

So we have to be able to measure the energy we consume and use, and we do so with a unit called the calorie.

所以，我們必須知道如何計算我們攝取和消耗的熱量我們用一個叫做卡路里的單位來幫助我們計算

One calorie, the kind we measure in food, also called a large calorie, is defined as the amount of energy it would take to raise the temperature of one kilogram of water by one degree Celsius.

卡路里是我們用來計算食物的熱量的單位，也稱為一大卡一大卡的定義為可以將一公斤的水加熱攝氏一度的能量

Everything we consume has a calorie count, a measure of how much energy the item stores in its chemical bonds.

而我們所吃的每樣東西都有它的卡路里總量可以讓我們知道食物的化學鍵結中蘊藏了多少的能量

The average pizza slice has 272 calories, there are about 78 in a piece of bread, and an apple has about 52.

普通一片披薩有 272 的卡路里一片麵包大約有 78 的卡路里而蘋果則有 52 的卡路里

That energy is released during digestion, and stored in other molecules that can be broken down to provide energy when the body needs it.

透過消化，這些能量會被從食物中釋放出來，接著被儲存在分子中而這些分子會被分解以提供身體所需的能量

It's used in three ways: about 10% enables digestion, about 20% fuels physical activity, and the biggest chunk, around 70%, supports the basic functions of our organs and tissues.

這些能量使用於三個地方：其中的10%被用來進行消化作用 (消化食物消耗的熱量)20% 運作身體的活動 (身體運動消耗的熱量)而大半，約 70% 的的能量負責支撐我們身體器官或組織的功能運作

That third usage corresponds to your basal metabolic rate, a number of calories you would need to survive if you weren't eating or moving around.

第三個與你的基礎代謝率有關 (就是正常人一天要消秏的熱量)在你不動也不吃的狀態下，你的身體最基本需要消耗的最低熱量

Add in some physical activity and digestion, and you arrive at the official guidelines for how many calories the average person requires each day:

再加上一些運動和消化你就能算出一個人一天需要攝取卡路里的標準值你就能算出一個人一天需要攝取卡路里的標準值

2000 for women and 2500 for men.

女性需要 2000 卡路里，而男性需要 2500 卡路里

Those estimates are based on factors like average weight, physical activity and muscle mass.

這估計是根據平均體重、運動量、和肌肉量而來的

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

所以這代表每個人都需要攝取大約 2000 卡的卡路里嗎？

Not necessarily.

未必

If you're doing an energy guzzling activity, like cycling the Tour de France, your body could use up to 9000 calories per day.

如果你做一個高耗能的運動像是環法自行車賽你的身體每天則可以消耗到 9000 多卡的卡路里

Pregnancy requires slightly more calories than usual, and elderly people typically have a slower metabolic rate, energy is burned more gradually, so less is needed.

懷孕時則會消耗比平常多一點的卡路里而老年人則有著較低的新陳代謝率能量消耗得較慢，所以需要攝取的熱量也相對的少

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

在你計算卡路里前，你應該知道這些事項

The calorie counts on nutrition labels measure how much energy the food contains, not how much energy you can actually get out of it.

食物包裝上的營養成分計算的是食物所含的熱量而不是你實際上能攝取到的熱量

Fibrous foods like celery and whole wheat take more energy to digest, so you'd actually wind up with less energy from a 100 calorie serving of celery than a 100 calorie serving of potato chips.

纖維性的食物，像是芹菜和全麥，都需要更多的能量能消化所以，其實你吃 100 卡路里的芹菜所攝取的能量會比 100 卡路里的洋芋片來得少

Not to mention the fact that some foods offer nutrients like protein and vitamins, while others provide far less nutritional value.

更何況在有些食物中也含了其他營養成分，像是蛋白質和維他命；而另外一些食物甚至有著較低的營養價值

Eating too many of those foods could leave you overweight and malnourished.

如果吃太多這樣不營養的食物，則會導致你過胖或是營養不良

And even with the exact same food, different people might not get the same number of calories.

另一方面，即使你們都吃一樣的食物，不代表你們都攝取一樣的卡路里

Variations in things like enzyme levels, gut bacteria, and even intestine length, means that every individual's ability to extract energy from food is a little different.

因為每個人都有著不同的酵素含量、腸道細菌、甚至是腸子長度因此，每個人吸收熱量的能力都不一樣

So a calorie is a useful energy measure, but to work out exactly how many of them each of us requires we need to factor in things like exercise, food type, and our body's ability to process energy.

所以卡路里是個實用的能量計算方式但是要算出我們每個人所需要的熱量我們必須考慮其他因素，像是運動、食物種類、和我們身體消化的能力

Good luck finding all of that on a nutrition label.

如果你想在營養標示上找到所有資訊的話，祝你好運！