What percentage of these "before and after" pictures advertising diets or fitness vhs tapes, are actually "after and before" pictures?

None. its an advertising scam…I have seen supposedly ordinary people who lost 20 Lbs in 13 weeks…not much and I read the fine print..always read that!

It states so and so lost 20 or 30 lbs by following this diet but also coupling it with exercise so many times per week too.

My self I lost 80 lbs taking” Slim Fast Ultra”( faster) and that took almost 8 months nut I also was working three jobs and hiking on days off.

It stayed off for three years until I had an accident and could not exercise etc..gained some weight but not that much.

Later other complications..off work and no use of hands or wrists ( tendons) and gained weight on medical leave.

Still struggling now, but on “Slim Fast”
( no Ultra available , prob was a food hunger suppressant?)

Going hiking now that its Summer and feel energetic already after only two days of only having the slim fast for only replacing Breakfast.

I eat a normal ( light) supper.

https://www.youtube.com/watch?v=p6Op2P2153A

@Caravanfan

Wow! I bet a lot of celebrities use that.

I thought that a lot of before pictures were pregnant women?

And after they had their baby then the after shot is shown months later?
Otherwise how come the before photographs always look big around only the stomach..pregnant?

Some diets work for some people, but not many diets work for very many people.

Metabolife worked well for me back in the 1999/2000 era. Fifty pounds lost in 2–½ months.

But nothing else has—not even those tiny portion mealette-style plans haven’t done diddly, nor has anything shown on Doctor Oz—like Green Coffee or Green tea. So results really don’t mean anything, faked or not.

I’m going to say none.

Even if they are actually before and after of the same person they are false representations. I can look 15 pounds thinner with make-up, hair, clothing, standing up straight, and sucking in my gut.