(CBS) Each year, people spend more than $40 billion on products
designed to help them slim down. None of them seem to be working very
well.

Now along comes hoodia. Never heard of it? Soon it'll be tripping off
your tongue, because hoodia is a natural substance that literally
takes your appetite away.

It's very different from diet stimulants like Ephedra and Phenfen
that are now banned because of dangerous side effects. Hoodia doesn't
stimulate at all. Scientists say it fools the brain by making you
think you’re full, even if you've eaten just a morsel. Correspondent
Lesley Stahl reports.
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Hoodia is a bitter-tasting cactus-like plant. 60 Minutes was told
that if it wanted to try hoodia, it would have to go to Africa. Why?
Because the only place in the world where hoodia grows wild is in the
Kalahari Desert of South Africa.

Nigel Crawhall, a linguist and interpreter, hired an experienced
tracker named Toppies Kruiper, a local aboriginal Bushman, to help
find it. The Bushmen were featured in the movie “The Gods Must Be
Crazy.”

Kruiper led 60 Minutes crews out into the desert. Stahl asked him if
he ate hoodia. "I really like to eat them when the new rains have
come," says Kruiper, speaking through the interpreter. "Then they're
really quite delicious."

When we located the plant, Kruiper cut off a stalk that looked like a
small spiky pickle, and removed the sharp spines. In the interest of
science, Stahl ate it. She described the taste as "a little cucumbery
in texture, but not bad."

So how did it work? Stahl says she had no after effects – no funny
taste in her mouth, no queasy stomach, and no racing heart. She also
wasn't hungry all day, even when she would normally have a pang
around mealtime. And, she also had no desire to eat or drink the
entire day. "I'd have to say it did work," says Stahl.

Although the West is just discovering hoodia, the Bushmen of the
Kalahari have been eating it for a very long time. After all, they
have been living off the land in southern Africa for more than
100,000 years.

Some of the Bushmen, like Anna Swartz, still live in old traditional
huts, and cook so-called Bush food gathered from the desert the
old-fashioned way.

The first scientific investigation of the plant was conducted at
South Africa’s national laboratory. Because Bushmen were known to eat
hoodia, it was included in a study of indigenous foods.

"What they found was when they fed it to animals, the animals ate it
and lost weight," says Dr. Richard Dixey, who heads an English
pharmaceutical company called Phytopharm that is trying to develop
weight-loss products based on hoodia.

Was hoodia's potential application as an appetite suppressant
immediately obvious?

"No, it took them a long time. In fact, the original research was
done in the mid 1960s," says Dixey.


It took the South African national laboratory 30 years to isolate and
identify the specific appetite-suppressing ingredient in hoodia. When
they found it, they applied for a patent and licensed it to
Phytopharm.

Phytopharm has spent more than $20 million so far on research,
including clinical trials with obese volunteers that have yielded
promising results. Subjects given hoodia ended up eating about 1,000
calories a day less than those in the control group. To put that in
perspective, the average American man consumes about 2,600 calories a
day; a woman about 1,900.

"If you take this compound every day, your wish to eat goes down. And
we've seen that very, very dramatically," says Dixey.

But why do you need a patent for a plant? "The patent is on the
application of the plant as a weight-loss material. And, of course,
the active compounds within the plant. It’s not on the plant itself,"
says Dixey.

So no one else can use hoodia for weight loss? "As a
weight-management product without infringing the patent, that’s
correct," says Dixey.

But what does that say about all these weight-loss products that
claim to have hoodia in it? Trimspa says its X32 pills contain 75 mg
of hoodia. The company is pushing its product with an ad campaign
featuring Anna Nicole Smith, even though the FDA has notified Trimspa
that it hasn’t demonstrated that the product is safe.

Some companies have even used the results of Phytopharm’s clinical
tests to market their products.