Hypothyroidism is the term to describe an underactive thyroid. This means the gland is producing less hormone than it should which in turn causes the metabolism to run too slow.
Dr Renee Hoenderkamp, GP and medical writer, touched on the subject in her online video blog.
She explained: "I have a vested interested in this topic as I lost my thyroid to a nasty lump about seven years ago. Across that time I have built up lots of experience, done lots of research and been through the mill."
Do read the comments. Gillian23 is very underwhelming!