Word Distinction: Degrees of Fatness

If you want to be polite about someone, do not say they are fat. (Rather) overweight is a more polite way of saying the same thing. Plump is most often used of women and children and means “slightly (and pleasantly) fat”. Chubby (used of babies and children) also means “pleasantly fat”. Stout means “rather fat and heavy” and tubby means “short and rather fat, especially in the stomach”. If someone is extremely fat and unhealthy they are said to be obese.
In the US and the UK it is generally thought to be unattractive to be fat, and many people, especially women, often go on diets in order to try to lose weight. Some people believe they experience discrimination (= unfair treatment, especially at work) because they are fat.
A health farm is a place, especially in the country, where people go for a healthful regimen of regular exercise, special diets, etc. Some of these places are very expensive and they are visited by those who wish to improve their health by losing weight.