The real truth about hoodia and weight loss...

Losing weight requires burning more calories than you consume on a consistent basis. Unfortunately, the drive to eat is very powerful. If you've spent more than a few days on a diet, you're probably familiar with that intense sense of hunger that just won't go away.

If we're to believe the hype, a small cactus-like plant in the South African Kalahari Desert called Hoodia gordonii could hold the key. The San Bushmen of the Kalahari have been eating hoodia (pronounced HOO-dee-uh) for thousands of years to stave off hunger during long hunting trips.

Known to the Bushmen as ghaap, hoodia grows to seven feet tall in the arid and inhospitable environment of the Kalahari. The fleshy, finger-like stems are peeled and chewed by the Bushmen as they prepare to spend days without food in the desert.

They cut a piece of the plant, which is about the size of a cucumber, and eat it. It takes a piece of fresh hoodia, about 2 or 3 inches long, to get the appetite suppressing benefit.

So, why should you care about a plant in the Kalahari Desert?

Supplements that supposedly contain hoodia are now widely available on the Internet. Their manufacturers claim they'll help you lose weight by taking away your desire to eat.

Do they work? We'll come to that in a moment. First, let's take a closer look at the reasons why hoodia has generated so much interest.

P57

In the 1990s, South African scientists isolated the active ingredient in Hoodia gordonii responsible for the appetite reducing effect, which has become known as P57. In 1997, this was licensed exclusively to British pharmaceutical company Phytopharm by the South African Council for Scientific and Industrial Research.

Research carried out by Phytopharm shows that a group of 18 morbidly obese volunteers cut the number of calories they consumed by as much as 1000 calories per day after taking the hoodia extract for two weeks (see below).

However, this is only one small "in-house" study, and I couldn't find it in any peer-reviewed journal.

Research published in a peer-reviewed journal carries more credibility because it undergoes scrutiny from a panel of experts. Without more information about how the study was done, it's difficult to make a judgment about what the results really mean for you and me.

Hoodia was also featured in a TV documentary shown on BBC2 in 2003. In the documentary, BBC correspondent Tom Mangold drove into the desert so he and his cameraman could try it for themselves.

"Once there, we found an unattractive plant which sprouts about 10 tentacles, and is the size of a long cucumber. Each tentacle is covered in spikes which need to be carefully peeled. Inside is a slightly unpleasant-tasting, fleshy plant."

"At about 6.00pm I ate about half a banana size — and later so did my cameraman. Soon after, we began the four hour drive back to Capetown."

"The plant is said to have a feel-good almost aphrodisiac quality, and I have to say, we felt good. But more significantly, we did not even think about food. Our brains really were telling us we were full. It was a magnificent deception."

"Dinner time came and went. We reached our hotel at about midnight and went to bed without food. And the next day, neither of us wanted nor ate breakfast. I ate lunch but without appetite and very little pleasure. Partial then full appetite returned slowly after 24 hours."

How does hoodia work?

According to Phytopharm chief Dr Richard Dixey, P57 targets the satiety centre in the brain, known as the hypothalamus.

"There is a part of your brain, the hypothalamus," says Dixey. "Within that mid-brain there are nerve cells that sense glucose sugar. When you eat, blood sugar goes up because of the food, these cells start firing and now you are full. What the Hoodia seems to contain is a molecule that is about 10,000 times as active as glucose. It goes to the mid-brain and actually makes those nerve cells fire as if you were full. But you have not eaten. Nor do you want to."

This has led a number of businesses to market hoodia products on the back of Phytopharm's research. "We have been appalled by the number of companies that have used our data," says Dixey.

"Yet our manufacturing technique, nor the dosage used, has ever been in the public domain. These companies are making wild and unsubstantiated claims, without any evidence for the product they are selling."

Obesity drug

Phytopharm initially pinned its hopes for hoodia on the diet drug market. It sold the worldwide marketing rights to Pfizer (the company behind Viagra), which intended to study the molecule and develop a synthetic version for use as an oral prescription drug to treat obesity. However, Pfizer discontinued clinical development of P57 and returned the rights to Phytopharm in 2003.

According to a Phytopharm press release (which, given the large drop in the value of Phytopharm stock when the announcement was made, may or may not be entirely accurate), Pfizer decided that the "development of P57 might be best achieved by another organization."

Of course, the fact that Pfizer returned the rights could mean that the stuff didn't work in oral form. Maybe it was simply too expensive.

"For Pfizer to release something dealing with obesity," says Paul Hutson, associate professor in the University of Wisconsin-Madison School of Pharmacy, "suggests to me that they felt there was no merit to its oral use. [But] there's really no human literature that I can point you to, to prove or disprove this stuff."

Tests show that P57 works well when it's injected into rats. "They tended to appear more satiated," says Hutson of the rats. "That's the only reference I can suggest from a legitimate scientific journal that I have access to."

Unilever obtained the global rights to P57 in December 2004. The first new hoodia products will “probably reach the market in three years,” according to Unilever spokesman Trevor Gorin, and may come under the Slim Fast brand or be included in other Unilever brands.

So, what about all these hoodia supplements on the market right now? Do they actually work?

These products claim to contain dried, powdered hoodia. However, Hoodia gordonii is very rare and is protected by national conservation laws in South Africa and Namibia. It can only be collected or grown with a permit.

Moreover, these products are not regulated or inspected. Given the fact there is presently no accepted standard for assessing the quality of hoodia as an ingredient, the quality of these supplements remains largely uncertain. I'm guessing that many don't contain any Hoodia gordonii at all. And even if they do contain hoodia, there are no published clinical trials to establish an optimal dose that is safe and effective.

Before I write to you about a supplement, I usually try it first. Hoodia is one of the exceptions. I've been wrong about this kind of thing before, and my skepticism about hoodia supplements could be totally misplaced.

But, it's also possible that the Federal Trade Commission will soon be charging hoodia marketers for claiming, falsely and without substantiation, that their products can cause weight loss, just as they did with CortiSlim in 2004.

Compounds that help with appetite control are a viable way to help you lose fat. Most of the weight loss seen with ephedrine and caffeine, for example, comes from their effect on appetite and calorie intake (see Is Ephedra Making a Comeback? in the Members-Only Area). However, until there's more data on hoodia, it's not a supplement that I would use myself or recommend to you.

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