Dr Tony Goldstone
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Health Explained: What is fat?

1 September 2010 Last updated at 18:53 BST

Dr Tony Goldstone, an obesity expert from the MRC Clinical Sciences Centre at Hammersmith Hospital, Imperial College London, explains what fat is.

Using an MRI machine, he explains why we need fat, how it differs, and why too much fat in the wrong place can be bad for us.