This club was not a club selling diet drinks (but it clearly did that). It was a club selling the social support group necessary to drink diet drinks. These diet drinks work (especially when combined with a modicum of exercise). What happens though is that normal people do not have the will-power to maintain a diet drink and exercise regime. My friend in Singapore did – but then he rowed competitively and people into rowing are austere driven people (think all those 4 AM starts).
But I am a fairly disciplined person and - without social support I could not drink these shakes.
In the richer-parts of our society we have a solution to diet-and-exercise will-power problem. We hire a personal trainer (usually someone cheerful, younger and good looking) and they cajole us into weight-loss. This is a “for-hire” personal support group.
But Herbalife is another valid mechanism of getting personal support – and it clearly worked on the customers I saw.