People will lose weight when they slim down with a friend.

人们若和朋友一起减肥，就会减轻体重。

《柯林斯英汉双解大词典》

Of course, people put on weight when they consume more calories than they burn off.

当然，当人们摄入的能到超过他们消耗的能量时，体重就会增加。

youdao

She says: \ I \ ve only ever lost weight when I was unhappy, not obsessing about being thin.

我只有当自己不快乐时才会减肥，所以我不会刻意想去苗条。

youdao

People with heart failure tend to gain weight because fluids build up when the heart can't pump enough blood.

VOA: standard.2010.06.04

Let me ask another question, if you give this-- and we'll talk about this in a later lecture, but if you give this diet to laboratory animal-- rats, mice, whatever-- it's very common for animals to gain a good bit of weight when given access to this diet.

我们来看另一个问题,如果你给,我们将在以后的课上讨论这个话题,但如果你给实验室动物,像小白鼠之类的,给予某种类型的饮食,这种饮食习惯会使得体重增加

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

This normal weight animal like this has its whole equilibrium thrown off, its homeostasis thrown off when its dietary conditions change.

在饮食条件发生变化时,这些正常体重动物的生理平衡被打破,于是摈弃了原来的平衡饮食

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

Mice from all three groups lost weight when they exercised, and their cholesterol levels lowered.

BBC: Exercise is good for health

Recent studies have suggested that up to 40% of people are under-weight when they're admitted to hospital.

BBC: NEWS | Health | 'I tried not to think about food'

The elderly and people of Asian descent are more likely to be at normal weight when diagnosed, for example.

CNN: Obesity paradox: Why being thin with diabetes is dangerous