You are what you eat, as the maxim goes. But are you really?

Let's break this question up into two parts: What are you? and What do you eat?
So what is the shape of the human body? If you answered "Blob", no one would blame you. But the problem is, you're a blob, I'm a blob, Anne Hathaway is an extremely shapely blob; but how do we distinguish them? We can't. At least not scientifically. No one has any trouble distinguishing me from Anne Hathaway.

But, this is science; so we have to do things in a logical, orderly, reproducible way.

Enter topology, the field of mathematics that deals with this kind of problem.
Here's what Wikipedia has to say about it:

Topology (from the Greek τόπος, "place", and λόγος, "study") is the mathematical study of shapes and topological spaces. It is an area of mathematics concerned with the properties of space that are preserved under continuous deformations including stretching and bending.

Let's take a quick detour to look into topology a little more deeply and then using that knowledge, address our original question.
The most important aspect of topology is that it is not concerned with the exact shape or figure of the body, only the characteristic properties.
Let's look at some common shapes for examples. Any three-dimensional body with no holes through it would be topologically equivalent to a sphere. An ellipsoid is also a sphere, that is compressed from the sides. Remember that in topology, stretching and bending are allowed, and don't constitute a shape change. So topologically, a sphere is equivalent to an ellipsoid.

A sphere  (http://en.wikipedia.org/wiki/Sphere#Topology) — A sphere (http://en.wikipedia.org/wiki/Sphere#Topology)

An ellipsoid (http://virtualmathmuseum.org/Surface/ellipsoid/ellipsoid.html)

Ok, but what does this have to do with the human body?
Well, the human body is three dimensional, but, it does have a hole through it.
Wait, what?!
Yup, your digestive canal is actually a direct hole from your mouth to your, well, butt.
That shape is defined as a toroid. Here's a picture of it.

A mesh diagram of a toroid.  (http://upload.wikimedia.org/wikipedia/commons/1/17/Torus.png) — A mesh diagram of a toroid. (http://upload.wikimedia.org/wikipedia/commons/1/17/Torus.png)

Look familiar?
The toroid also has another casual name. We also refer to it as - the donut.

So bringing it all together, the human body has the same (topological) shape as a donut.
And that provides us with the solution to our question.

You are what you eat; if you eat a donut.

Now you recognise it. And your mouth is watering.  (http://en.wikipedia.org/wiki/File:Glazed-Donut.jpg) — Now you recognise it. And your mouth is watering. (http://en.wikipedia.org/wiki/File:Glazed-Donut.jpg)

Now that we know about topology, let's take it a bit further too.

Topology also allows continuous deformations. Here, you can pull and bend the solid (theoretically, of course) in ways that arn't physically possible (typical mathematicians).
Consider your coffee mug. Doesn't seem like a simple object to model, but when you consider it from a topological perspective, it is still a distinct shape.

Did you guess what is was?
If you bend it, stretch it, and push a little bit...

A coffee mug is a donut too!

So the next time someone asks you what you are drinking, you can honestly tell them it's coffee in a donut.

Further reading:
http://en.wikipedia.org/wiki/Topology
http://mathworld.wolfram.com/Topology.html

Do you have any other interesting shapes that topologically form interesting things?
Let us know in the comments!