Do you eat to live or live to eat? We have a complicated relationship with food. But something we all share is appetite – our desire to eat.Our appetite is also not fixed, it changes across our lifespan as we age.

　　我们吃东西是为了求生?还是生活的意义在于享用美食?我们和事物的关系错综复杂。但是我们都共享食欲。我们的食欲也不是一成不变的，随着年龄的增长，我们的食欲也随之发生变化。

　　The first decade, 0-10

　　第一阶段：0-10

　　In early childhood, the body goes through rapid growth and dietary behaviour built up in early life can extend into adulthood, leading a fat child to become a fat adult.

　　童年早期，身体经历了快速的成长，早期养成的饮食习惯可以延续到成年，让一个肥胖的孩子成长为肥胖的成年人。

　　Fussiness or fear of particular foods can also contribute to meal time struggles for parents of young children, but a strategy of repeated tasting and learning in a positive environment can help children learn about unfamiliar but important foods, such as vegetables.Children should also experience some control, particularly in relation to portion size.

　　对于特定食物的挑剔或恐惧，还可以归功于孩子父母饭点时分的挣扎。但是，在积极的环境里采用反复品尝和学习的策略，可以帮助孩子习得一些不熟悉但是重要的食物，比如蔬菜。孩子还应该经历一些控制，尤其在食物份量上。

　　The second decade, 10-20

　　第二阶段：10-20

　　In the teenage years, a growth in appetite and stature driven by hormones, signals the arrival of puberty. How a teenager approaches food during this critical period will shape their lifestyle choices in later years.

　　青少年时期，受荷尔蒙的驱动，食欲和身高增长，这标志着青春期的到来。青少年如何在这一关键时期享用食物，将形成他未来的生活方式选择。

　　Unfortunately, without guidance, teenagers may adopt eating behaviours and food preferences associated with unhealthy consequences.

　　不幸地是，在没有指导的情况下，青少年可能会接受带来不健康后果的饮食行为和食物偏好。

　　Young women in general are more likely to suffer from nutritional deficiencies than young men because of their reproductive biology. Teenage girls who become pregnant are also at greater risk since their bodies are supporting their own growth in competition with that of the growing foetus.

　　基于繁殖生物学，通常情况下，年轻女性比年轻男性更容易饱受营养不良的折磨。怀孕的青春期少女也面临着更大的风险，因为她们的身体在支撑自我成长和婴儿成长间竞争。

　　The third decade, 20-30

　　第三阶段：20-30

　　As young adults, lifestyle changes such as going to college, getting married or living with a partner, and parenthood can promote weight gain.

　　作为年轻人，诸如上大学，结婚或者合住都会改变生活方式，当父母会增重。

　　Once accumulated, body fat is often difficult to lose. The body sends strong appetite signals to eat when we consume less than our energy needs, but the signals to prevent overeating are weaker, which can lead to a circle of over-consumption. There are many physiological and psychological factors that make eating less difficult to maintain over time. In an area of new research is to develop satiety, the sense of having eaten enough. This is helpful when trying to lose weight, since feeling hungry is one of the main barriers to eating less than your body says you need.

　　体内的脂肪一旦堆积，就很难消失。当我们吃的比能量需求少时，身体就会发出强烈的食欲信号，但是防止过量饮食的信号却比较弱，这会导致过量饮食。很多生理和心理因素让保持少量饮食变得困难。一个新的研究领域就是发展饱腹感。再减肥的时候，这个策略很有用，因为感到饥饿是减少饮食的主要障碍之一。

　　Different foods send different signals to the brain. It’s easy to eat a tub of ice cream, for example, because fat doesn’t trigger signals in the brain for us to stop eating. On the other hand, foods high in protein, water or fibre content make us feel fuller for longer.

　　不同的食物向大脑发送不同的信号。比方说，吃下一桶冰淇淋很简单，因为脂肪不会激发大脑停止吃东西的信号。另一方面，富含蛋白质，水或者纤维的食物能让我们获得更久的饱腹感。