fat and fats , food and foods

I don't totally agree with the above respondant.

Food:

While the term [food] as a general term to what we eat and [foods] can be referring to different food sources, like foods from animals, foods from plants, or as the above has said, foods from different countries...

It is not necessarily the same case for Fat/ Fats. The main difference is:

Fat:

-Use as a noun refers to the oily compound that are found in animal or plant tissues.
-Use as an adjective: He is fat.

WHILE FATS...
-is the plural of fat...

BUT MORE IMPORTANTLY,
-refers to the organic compound that are made up of triglycerides, i.e. the whole branch of lipids when talking of biochemistry (which I can have lots to talk about)

- fats must be included in a balanced diet to provide energy, precursor to turn on body mechnisms, and absorption of vitamins...

Food can be used as plural as well as singular (Foods and Food)

We can say, Too many junk food is not good for you (a category)

we can also say, The foods of China, Japan and Korea are very tasty. (food of three different countries)

Such is the case with the word fat

2007-01-30 09:36:55 補充：
For example we can say: A fat analysis revealed I have 18.6% body fat.(singular) or There are many different kinds of fats.(plural). The word fat could also be used as an adjective when describing a noun: The dog was a fat one.

2007-01-30 10:04:38 補充：
Sorry I have to break my answer into 2 parts, as I was in a meeting yesterday when I was trying to give my respond. Hopefully it is simplest enough for you to understand.