Why are nudists never hot?

[Oliver_W]

I'm watching Four In A Bed, and one of the B&B owners is a nudist ... And a saggy old man.

Why do they never look like Zac Efron or something?

[Alf]

When you're out in the cold in your birthday suit, you need a bit of meat on you, for warmth.

[Shaun]

I'd imagine not caring about being free and naked probably goes hand in hand with not caring what others think of your body.