You're about to listen to a BBC podcast and maybe it's when I had a hand in.

I'm Tammy Walker and I produce podcasts for the BBC.

My role is to give new and diverse creators a voice with the opportunity to build a career.

That's the thing I love about podcasts.

You start with just a good idea, but then you have the space to see where it goes.

And doing that at the BBC means we can really run with the best stories

while developing the most unique audio talent.

So if you like what you hear, why not check out the huge range of podcast we've got on BBC Sounds?

Hello and welcome to Crowd Science on the BBC World Service. I'm Marnie Chesterton. Normally we take a single question from you and travel the world to find answers.

But this week we've got the world, or rather,

questions from around the world to come to us

and we've set up a party in the studio.

And all of this is sparked off by a particular query from listener Regina.

Hi crowd science on the BBC World Service.

I'm Regina Ebonne and I'm calling you from Frankfurt and Germany.

I know researchers have found that our brains use quite a lot of energy.

My question for today's program is, can we lose weight just by sinking or concentrating really hard?

How much energy can I burn by thinking?

Thank you Regina.

Like I said, yours was not the only energy-themed email in the crowd science inbox.

Thanks to everyone intrigued by this topic.

So, we've picked a selection and lured three of University College London's finest scientists here to provide answers.

...