I could eat what I liked without getting fat.
After five minutes, the fat woman in the seat in front of me was asleep.
If you describe someone as fat, you are speaking in a very direct way, and this may be considered rude. If you want to say more politely that someone is rather fat, it is better to describe them as plump, or more informally, as chubby. Overweight and obese are used to describe someone who may have health problems because of their size or weight. Obese is also a medical term used to describe someone who is extremely fat or overweight. In general you should avoid using any of these words in the presence of the person you are describing.
用 fat 来形容某人肥胖过于直接，而且有可能会被认为没有礼貌。表达此意更礼貌的说法是 plump 或 chubby，其中 chubby更口语化。形容某人因块头过大或体重过重而出现健康问题时用 overweight 和 obese。obese 还是医学术语，用以形容某人极度肥胖或过重。一般说来，这些词都应该避免当面使用。