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.
你的体重取决于摄入、储存和消耗的热量，而这些因素又受到遗传和环境的共同作用。基因和环境既会影响你的生理机制（比如热量消耗的快慢），也会左右你的行为（比如选择吃什么食物）。这些因素相互作用，从生命孕育之初就与人相伴，一直到生命结束。
Genetic influences
遗传因素对体重的影响
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.
基因从多个方面诱导致胖因素，它能影响食欲、饱腹感（吃饱的感觉）、新陈代谢、进食冲动、体脂分布，还有进食减压的倾向。
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.
遗传因素对体重失调的影响大小因人而异。所以，为了做好体重管理，你需要大体了解基因对你的体重到底有多大作用。
How much of your weight depends on your genes？
遗传因素对你的体重有多大影响？
Genes are probably a significant contributor to your obesity if you have most or all of the following characteristics：
要是你的情况基本符合以下三点，你很可能受基因影响而过胖：
· You have been overweight for much of your life.
·有长期肥胖的烦恼。
· 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%.
·父母双方或一方或直系亲属中多人体重严重超标。父母双方都过胖的话，子女罹患肥胖症的概率高达80%。
· You can’t lose weight even when you increase your physical activity and stick to a low-calorie diet for many months.
·明明数月加强运动，且坚持低热量的饮食，却还是无法减重。
Genes are probably a lower contributor for you if you have most or all of the following characteristics：
如果你的情况基本符合以下三点，则基因对你胖瘦的影响较小：
· You are strongly influenced by the availability of food.
·你的体重主要由进食多少决定。
· You are moderately overweight， but you can lose weight when you follow a reasonable diet and exercise program.
·体重偏高，但是只要合理饮食，加上适量运动就能减重。
· 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.
·在节假日期间、改变饮食或锻炼习惯后，或是心理或社交方面出问题时，体重就会反弹。
Environmental causes of obesity
环境因素导致肥胖
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.
环境因素从生命初期就影响人的体重，甚至可以追溯到你出生之前。研究人员有时也把在母亲子宫内所受影响比作“胎儿编程”。与不吸烟的孕妇相比，孕妇吸烟会增加孩子超重的概率。同样地，母亲患有糖尿病也会增加孩子肥胖的可能性。研究人员认为，这些状况或许能改变发育中婴儿的新陈代谢，其影响在后续的成长中会逐渐显现。
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，与母乳喂养不到三个月的婴儿相比，母乳喂养超过三个月的婴儿在青春期肥胖的可能性较低。
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.
儿时的习惯往往伴随人的一生。小时候喝含糖碳酸饮料、吃高热量加工食品的孩子，会对这类饮食产生偏好，长大后保持这种饮食习惯，因而容易发胖。同样道理，小时候看电视、打游戏而不爱运动的孩子，日后会将久坐固化为习惯。
Many features of modern life promote weight gain. In short， today’s “obesogenic” environment2 encourages us to eat more and exercise less.
现代生活方式的许多特点都是发胖的诱因。简而言之，如今的“致胖”环境诱使人们吃得多，动得少。
The food factor as one of the causes of obesity
食物也是肥胖的诱因
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.
无论是购物中心、体育场，还是电影院，我们每到一处都有东西可吃。路边的停车休息区、全天无休的便利店，甚至健身房和健康会所里都能买到零食、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世纪50年代，快餐店提供的一份餐食份量适中，如今，餐食分量普遍激增，这种趋势还蔓延到许多其他餐饮品类，从曲奇饼干和爆米花到三明治和牛排，不一而足。以麦当劳为例，其标准份薯条的热量是该连锁品牌初创时的三倍。
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.
我们正摄入更多高热量的食物（尤其是咸味零食、碳酸饮料和比萨饼）——它们比低热量的蔬菜色拉和鲜果更常见。问题未必出在脂肪含量上；其实，许多低脂食品的热量奇高，因为想要食物更加美味可口，必然会添加大量糖分。
The exercise equation
锻炼对体重的影响
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.
美国政府目前推荐的运动量为每天一个小时的中高强度锻炼。实际上，能达到这一标准的美国人不到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.
我们的日常生活中没有太多运动的机会。儿童在学校里缺乏锻炼，体育课的课时老被削减。很多人开车上班，一整天坐在电脑显示屏前。因工作时间长，我们很难抽出时间去健身房、参加体育运动或者以其他形式锻炼身体。
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.
我们不再拎着购物袋到附近的商店走走逛逛，而是开车去一站式的超大商场，紧挨着商场入口停车，推着购物车采购，完了开车回家。吸尘器、洗碗机、吹叶机等许多电器的普及帮人们摆脱了几乎所有家务活的负担，也成了导致肥胖的原因之一。
Stress and related issues
压力相关的因素
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.
压力与影响体重的这些因素密切相联。许多家庭里父母都要上班，很难抽出时间采买、烹饪和享用健康的食物。电视新闻日夜不停，更频繁地报道绑架儿童和随机暴力的事件。这不但增加了心理压力，也让父母更不愿意放孩子骑车去公园玩耍。他们只好开车送孩子去玩伴那里，事先安排固定的活动，结果就是孩子的活动量减小，而家长的压力徒增。无论是接送孩子上下学、完成工作还是履行家庭责任都需要时间，让人们吃饭如打仗，牺牲睡眠时间，两者都会使人变胖。
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.
有研究人员指出，匆忙而不规律的饮食习惯正是导致肥胖的另一原因。大脑的节律中枢与下丘脑的食欲控制中枢关系紧密，这表明饥饿感和饱腹感皆受时间信号调控。不规律的饮食模式会打乱这种有效的信号调控，从而导致肥胖。
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.
研究还表明，睡得越少就越容易发胖。睡眠不足易导致调控饥饿感和食欲的激素紊乱，成为肥胖的另一诱因。
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.
压力和睡眠不足不但关系着心理健康，还影响日常饮食和胃口，就像我们每个人都有过焦虑不安、心烦意乱时狂吃饼干薯片的经历。反过来，超重和肥胖又会加剧情绪病的发作：如果你减肥老是失败，或减肥后总是反弹，屡试屡败的感觉会带来严重的挫折感，继而引发或加重焦虑和抑郁。
（译者为“《英语世界》杯”翻译大赛获奖者；单位：上海工程技术大学）
1 burn up烧掉，消耗，耗费。
2指在营养和运动两方面容易导致体重超标甚至肥胖的社会环境。
3 on the run 匆匆忙忙，忙个不停。 4 pacemaker 原义是赛跑中定速的领跑者，此处指下丘脑的视交叉上核，也被称为中枢生物钟，在昼夜节律的产生中起重要作用。 5 hypothalamus下丘脑是大脑中调节体温、昼夜节律、饥饿感和情绪等的关键部位。 6 temporal时间的。
Weight Management & 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.
