Sex is the most practical and funniest (full of fun) ways of losing weight.
Look how many calories you can burn:

Taking Off The Clothes
With her agreement 12 cal
Without her agreement 187 cal
Taking Off The Bra
With both hands 8 cal
With one hand 12 cal
With one hand being slapped 37 cal
With the mouth 85 cal
Putting On The Condom
With erection 6 cal
Without erection 315 cal
Preliminaries
Trying to find the clitoris 8 cal
Trying to find G spot 92 cal
Without caring at all 0 cal
When Doing It
Holding her up 12 cal
Just on the floor 8 cal
Positions
Daddy-mummy 12 cal
69 laying 8 cal
69 standing up 112 cal
Trolley 216 cal
Italian chandelier 912 cal
Having An Orgasm
Real 112 cal
Fake 315 cal
Post Orgasm
Staying in bed 18 cal
Jumping off the bed 36 cal
Explaining why she jumped off the bed 816 cal
Getting The Second Erection
Between 16 and 19 years of age 12 cal
From 20 to 29 36 cal
From 30 to 39 108 cal
From 40 to 49 324 cal
From 50 to 59 972 cal
Over 60 2916 cal
Putting On The Clothes
Quietly 32 cal
Being in a hurry 98 cal
With her husband opening the door 1218 cal