I remember about five (?) years ago when both the English language terrestrial channels had basically the same schedule, anchored around a second-rate film at 9.30. Then ATV World changed to a lineup that was based around documentaries, though they subsequently added more drama and a lot of sport (mainly horse racing). Gradually, TVB Pearl has added more documentaries and drama and also cut back on the films. So now the two channels once again have similar schedules!
Pearl insist on creating themes for the programs they buy, including the so-called "MI 9-30" slot (they don't seem to care that actually the programmes are transmitted at 9.35 or 9.40 rather than 9.30). I have to give them credit for showing some interesting documentaries in this slot, usually from the BBC or Discovery Channel.
This week they showed a BBC 'Horizon' documentary about the Atkins Diet that was first aired in the UK in January. The programme got significant coverage at the time (here for example, registration required) because the diet has been regarded as something of a mystery scientifically. How could people eat more and still lose weight?
Dr Atkins's theory is that the body consumed more calories converting fat (rather than carbohydrates) into energy, but the program came up with a simpler and much less controversial explanation - people on the Atkins diet actually consume fewer calories, so it is no surprise that they lose weight. Although the diet says that you can eat as much as you want, people actually consume fewer calories than before they started the diet, but it's not totally clear why this should be the case. The programme tested the theory that eating more fat makes you feel full but in fact the reverse seems to be true. In fact, no-one fully understands how appetite works - clearly people feel hungry when they have no physical need to eat, and this is a major factor in obesity (especially when food is so readily available and so cheap), so if scientists can figure that one out then they could help a lot of people.
During most of the programme there seemed to be some confusion between fat and protein, presumably because Atkins argued that you could eat unlimited quantities of both. This was eventually addressed at the end of the programme, and here (once again) we seem to return to the realm of common sense - a high-protein diet is good for you, whereas a high-fat diet is not. If you eat more protein, slightly more fat and cut down on carbohydrates then you will lose weight. This runs counter to orthodoxy of the food triangle, but is less controversial than simply saying that a high-fat diet will make you thin.
One of the stranger aspects of the diet is that it induces Ketosis (the process the body undergoes when you stop eating carbohydrates and the body starts turning fat into energy). This has always been one aspect of the diet that concerned me - firstly because it seems unnatural, and secondly because it means that if you abandon the diet you have to start again with the first stage. The scientific study (on two volunteers locked in a room for 20 days each) seemed to prove that the body is not burning additional calories to turn fat into energy, and no significant number of calories are lost in urine. Since these are the two main benefits that Ketosis is supposed to bring, it doesn't seem that the Atkins diet works in the way that Dr Atkins believed.
However, if the Atkins diet manages to get people to consume fewer calories whilst feeling happy with their diet and not feeling hungry then clearly it is successful, though various mysteries remain. It is possible that people do indeed feel less hungry when they eat more protein, but alternatively it may be psychological - feeling that you can eat whatever you like at lunch or dinner may make you less likely to eat snacks between meals. The other factor is surely that Atkins limits what you can eat and cuts out many of the obvious snack foods (biscuits, potato chips, sweets, etc). If you have the discipline to stick to that regime then you can hardly fail to lose weight.
The irony here is that the very success of Atkins may create new problems. So many people are following the diet that there are now a range of special low-carbohydrate foods available, some sold or endorsed by Atkins Nutrionals. If it is possible to eat large quantities of these foods (in addition to the normal protein and fat diet) and lose weight, then that would prove that the science behind the Atkins diet is correct. My guess is that it won't work, and people are better sticking to the real principles of the diet rather than cheating in this way.
I am willing to believe that eating a low-carbohydrate diet can be beneficial, and I think that Robert Atkins was right to challenge the orthodox view of what we should eat, but I seriously doubt that he was correct to argue that you can eat unlimited amounts of fat and still lose weight. The Horizon programme addressed a number of the claims that are made about the Atkins diet, but there is still more to understand about why it works.