Why People Become Overweight人到底為什么會超重

Your weight depends on the number of calories you consume， how many of those calories you store， and how many you burn up1. But each of these factors is influenced by a combination of genes and environment. Both can affect your physiology （such as how fast you burn calories） as well as your behavior （the types of foods you choose to eat， for instance）. The interplay between all these factors begins at the moment of your conception and continues throughout your life.

你的體重取決于攝入、儲存和消耗的熱量，而這些因素又受到遺傳和環境的共同作用。基因和環境既會影響你的生理機制（比如熱量消耗的快慢），也會左右你的行為（比如選擇吃什么食物）。這些因素相互作用，從生命孕育之初就與人相伴，一直到生命結束。

Genetic influences

遺傳因素對體重的影響

Genes contribute to the causes of obesity in many ways， by affecting appetite， satiety （the sense of fullness）， metabolism， food cravings， body-fat distribution， and the tendency to use eating as a way to cope with stress.

基因從多個方面誘導致胖因素，它能影響食欲、飽腹感（吃飽的感覺）、新陳代謝、進食沖動、體脂分布，還有進食減壓的傾向。

The strength of the genetic influence on weight disorders varies quite a bit from person to person. Having a rough idea of how large a role genes play in your weight may be helpful in terms of treating your weight problems.

遺傳因素對體重失調的影響大小因人而異。所以，為了做好體重管理，你需要大體了解基因對你的體重到底有多大作用。

How much of your weight depends on your genes？

遺傳因素對你的體重有多大影響？

Genes are probably a significant contributor to your obesity if you have most or all of the following characteristics：

要是你的情況基本符合以下三點，你很可能受基因影響而過胖：

· You have been overweight for much of your life.

·有長期肥胖的煩惱。

· One or both of your parents or several other blood relatives are significantly overweight. If both of your parents have obesity， your likelihood of developing obesity is as high as 80%.

·父母雙方或一方或直系親屬中多人體重嚴重超標。父母雙方都過胖的話，子女罹患肥胖癥的概率高達80%。

· You can’t lose weight even when you increase your physical activity and stick to a low-calorie diet for many months.

·明明數月加強運動，且堅持低熱量的飲食，卻還是無法減重。

Genes are probably a lower contributor for you if you have most or all of the following characteristics：

如果你的情況基本符合以下三點，則基因對你胖瘦的影響較小：

· You are strongly influenced by the availability of food.

·你的體重主要由進食多少決定。

· You are moderately overweight， but you can lose weight when you follow a reasonable diet and exercise program.

·體重偏高，但是只要合理飲食，加上適量運動就能減重。

· You regain lost weight during the holiday season， after changing your eating or exercise habits， or at times when you experience psychological or social problems.

·在節假日期間、改變飲食或鍛煉習慣后，或是心理或社交方面出問題時，體重就會反彈。

Environmental causes of obesity

環境因素導致肥胖

Environmental influences come into play very early， even before you’re born. Researchers sometimes call these in-utero exposures “fetal programming.” Babies of mothers who smoked during pregnancy are more likely to become overweight than those whose mothers didn’t smoke. The same is true for babies born to mothers who had diabetes. Researchers believe these conditions may somehow alter the growing baby’s metabolism in ways that show up later in life.

環境因素從生命初期就影響人的體重，甚至可以追溯到你出生之前。研究人員有時也把在母親子宮內所受影響比作“胎兒編程”。與不吸煙的孕婦相比，孕婦吸煙會增加孩子超重的概率。同樣地，母親患有糖尿病也會增加孩子肥胖的可能性。研究人員認為，這些狀況或許能改變發育中嬰兒的新陳代謝，其影響在后續的成長中會逐漸顯現。

After birth， babies who are breast-fed for more than three months are less likely to have obesity as adolescents compared with infants who are breast-fed for less than three months.

出生之后，與母乳喂養不到三個月的嬰兒相比，母乳喂養超過三個月的嬰兒在青春期肥胖的可能性較低。

Childhood habits often stick with people for the rest of their lives. Kids who drink sugary sodas and eat high-calorie， processed foods develop a taste for these products and continue eating them as adults， which tends to promote weight gain. Likewise， kids who watch television and play video games instead of being active may be programming themselves for a sedentary future.

兒時的習慣往往伴隨人的一生。小時候喝含糖碳酸飲料、吃高熱量加工食品的孩子，會對這類飲食產生偏好，長大后保持這種飲食習慣，因而容易發胖。同樣道理，小時候看電視、打游戲而不愛運動的孩子，日后會將久坐固化為習慣。

Many features of modern life promote weight gain. In short， today’s “obesogenic” environment2 encourages us to eat more and exercise less.

現代生活方式的許多特點都是發胖的誘因。簡而言之，如今的“致胖”環境誘使人們吃得多，動得少。

The food factor as one of the causes of obesity

食物也是肥胖的誘因

Practically everywhere we go—shopping centers， sports stadiums， movie theaters—food is readily available. You can buy snacks or meals at roadside rest stops， 24-hour convenience stores， even gyms and health clubs.

無論是購物中心、體育場，還是電影院，我們每到一處都有東西可吃。路邊的停車休息區、全天無休的便利店，甚至健身房和健康會所里都能買到零食、吃到正餐。

In the 1950s， fast-food restaurants offered one portion size. Today， portion sizes have ballooned， a trend that has spilled over into many other foods， from cookies and popcorn to sandwiches and steaks. A typical serving of French fries from McDonald’s contains three times more calories than when the franchise began.

在20世紀50年代，快餐店提供的一份餐食份量適中，如今，餐食分量普遍激增，這種趨勢還蔓延到許多其他餐飲品類，從曲奇餅干和爆米花到三明治和牛排，不一而足。以麥當勞為例，其標準份薯條的熱量是該連鎖品牌初創時的三倍。

We’re also eating more high-calorie foods （especially salty snacks， soft drinks， and pizza）， which are much more readily available than lower-calorie choices like salads and whole fruits. Fat isn’t necessarily the problem; in fact， many low-fat foods are very high in calories because they contain large amounts of sugar to improve their taste and palatability.

我們正攝入更多高熱量的食物（尤其是咸味零食、碳酸飲料和比薩餅）——它們比低熱量的蔬菜色拉和鮮果更常見。問題未必出在脂肪含量上；其實，許多低脂食品的熱量奇高，因為想要食物更加美味可口，必然會添加大量糖分。

The exercise equation

鍛煉對體重的影響

The government’s current recommendations for exercise call for an hour of moderate to vigorous exercise a day. But fewer than 25% of Americans meet that goal.

美國政府目前推薦的運動量為每天一個小時的中高強度鍛煉。實際上，能達到這一標準的美國人不到1/4。

Our daily lives don’t offer many opportunities for activity. Children don’t exercise as much in school， often because of cutbacks in physical education classes. Many people drive to work and spend much of the day sitting at a computer terminal. Because we work long hours， we have trouble finding the time to go to the gym， play a sport， or exercise in other ways.

我們的日常生活中沒有太多運動的機會。兒童在學校里缺乏鍛煉，體育課的課時老被削減。很多人開車上班，一整天坐在電腦顯示屏前。因工作時間長，我們很難抽出時間去健身房、參加體育運動或者以其他形式鍛煉身體。

Instead of walking to local shops and toting shopping bags， we drive to one-stop megastores， where we park close to the entrance， wheel our purchases in a shopping cart， and drive home. The widespread use of vacuum cleaners， dishwashers， leaf blowers， and a host of other appliances takes nearly all the physical effort out of daily chores and can contribute as one of the causes of obesity.

我們不再拎著購物袋到附近的商店走走逛逛，而是開車去一站式的超大商場，緊挨著商場入口停車，推著購物車采購，完了開車回家。吸塵器、洗碗機、吹葉機等許多電器的普及幫人們擺脫了幾乎所有家務活的負擔，也成了導致肥胖的原因之一。

Stress and related issues

壓力相關的因素

Stress is a common thread intertwining these factors. In many families， both parents work， which makes it harder to find time for families to shop， prepare， and eat healthy foods together. Round-the-clock TV news means we hear more frequent reports of child abductions and random violent acts. This does more than increase stress levels; it also makes parents more reluctant to allow children to ride their bikes to the park to play. Parents end up driving kids to play dates and structured activities， which means less activity for the kids and more stress for parents. Time pressures—whether for school， work， or family obligations—often lead people to eat on the run3 and to sacrifice sleep， both of which can contribute to weight gain.

壓力與影響體重的這些因素密切相聯。許多家庭里父母都要上班，很難抽出時間采買、烹飪和享用健康的食物。電視新聞日夜不停，更頻繁地報道綁架兒童和隨機暴力的事件。這不但增加了心理壓力，也讓父母更不愿意放孩子騎車去公園玩耍。他們只好開車送孩子去玩伴那里，事先安排固定的活動，結果就是孩子的活動量減小，而家長的壓力徒增。無論是接送孩子上下學、完成工作還是履行家庭責任都需要時間，讓人們吃飯如打仗，犧牲睡眠時間，兩者都會使人變胖。

Some researchers also think that the very act of eating irregularly and on the run may be another one of the causes of obesity. Close connections between the brain’s pacemaker4 and the appetite control center in the hypothalamus5 suggest that hunger and satiety are affected by temporal6 cues. Irregular eating patterns may disrupt the effectiveness of these cues in a way that promotes obesity.

有研究人員指出，匆忙而不規律的飲食習慣正是導致肥胖的另一原因。大腦的節律中樞與下丘腦的食欲控制中樞關系緊密，這表明饑餓感和飽腹感皆受時間信號調控。不規律的飲食模式會打亂這種有效的信號調控，從而導致肥胖。

Similarly， research shows that the less you sleep， the more likely you are to gain weight. Lack of sufficient sleep tends to disrupt hormones that control hunger and appetite and could be another one of the causes of obesity.

研究還表明，睡得越少就越容易發胖。睡眠不足易導致調控饑餓感和食欲的激素紊亂，成為肥胖的另一誘因。

Stress and lack of sleep are closely connected to psychological well-being， which can also affect diet and appetite， as anyone who’s ever gorged on cookies or potato chips when feeling anxious or sad can attest. In turn， overweight and obesity themselves can promote emotional disorders： If you repeatedly try to lose weight and fail， or if you succeed in losing weight only to gain it all back， the struggle can cause tremendous frustration over time， which can cause or worsen anxiety and depression.

壓力和睡眠不足不但關系著心理健康，還影響日常飲食和胃口，就像我們每個人都有過焦慮不安、心煩意亂時狂吃餅干薯片的經歷。反過來，超重和肥胖又會加劇情緒病的發作：如果你減肥老是失敗，或減肥后總是反彈，屢試屢敗的感覺會帶來嚴重的挫折感，繼而引發或加重焦慮和抑郁。

（譯者為“《英語世界》杯”翻譯大賽獲獎者；單位：上海工程技術大學）

1 burn up燒掉，消耗，耗費。

2指在營養和運動兩方面容易導致體重超標甚至肥胖的社會環境。

3 on the run 匆匆忙忙，忙個不停。" 4 pacemaker 原義是賽跑中定速的領跑者，此處指下丘腦的視交叉上核，也被稱為中樞生物鐘，在晝夜節律的產生中起重要作用。" 5 hypothalamus下丘腦是大腦中調節體溫、晝夜節律、饑餓感和情緒等的關鍵部位。" 6 temporal時間的。

Weight Management amp; Healthy Living Tips

Weight management requires ongoing efforts， and you can start by taking small steps to make healthy habits a priority every day.

Try these tips to help manage your weight and stay active.

· Add motion to your day. Schedule time for physical activity and stick to it. Any physical activity， even for a short time， is a good thing.

· Have healthy snacks on hand. Look for snacks that are low in added sugar and salt， like fresh fruit or hummus with sliced veggies.

· Reduce screen time and time spent sitting. Turn off the devices and take a walk， try a new sport with your family， or create a playlist of favorite songs and have a dance contest.

· Use a food diary to track your meals. Whether you use an app on your phone or write it down， track your meals to help you discover changes to help you lose weight.

· Be prepared for setbacks—they are normal. You may have setbacks on your active and healthy journey， but don’t let them hold you back. Reach out to family and friends for support.