Where are you starting from?
The dietary restriction programme is not a weight-reducing approach as such. Its two aims are: health promotion (whether this be prevention of normal / common age-related health problems, or recovery from current ill health); and promotion of life extension. It is clearly quite impossible to guarantee that either of these aims will be achieved, and so anyone who is applying the methods must understand that they alone will able to judge whether or not they are sufficiently impressed by the evidence to become motivated to apply the programme, and ultimately whether they are pleased with the results.

Although the aims are not weight reduction, dietary (calorie) restriction almost always leads to this, and we must be clear that changes in weight are often an important guide to the way you are responding to the programme (and therefore to how efficiently you are applying the methods).

Assuming your age and health status do not bar you from applying the diet, your first step is to establish an important guideline, and this requires that you determine your 'set point' weight level.

How do you find your 'set point'?
If you have remained fairly stable since your 20s or early 30s, note down your average weight during that time. This is your 'set point. If you have steadily gained weight since that period of your life, then note down what your average weight was in your 20s or early 30s. This is your 'set point. If you have experienced a rapid weight gain (or loss) then this should be investigated by a health professional before you adopt any of the methods outlined. There could, for example, be a hormonal or other imbalance which requires attention.

Once you have established your 'set point' weight level you need to keep it in mind as the dietary approach progresses, ensuring that at no time does your weight fall below it by more than 25 per cent. For example, if your 'set point' is 60 kilos (1321b/9.5 stone) you must not let your weight drop below 45 kilos (991b/7 stone). If your 'set point' is 80 kilos (1761b/12.5 stone) your weight should not be allowed to drop below 60 kilos (1321b/9.5 stone). Simple arithmetic, using the 'set point' as your guide, will give you your absolute limit of weight loss below which safety is being risked.

On the other hand, in order to achieve benefits from the diet you should try to ensure that if your 'set point' and your present weight are the same, that after 12 months you have achieved at least a 10 per cent reduction in weight (which is also a 10 per cent reduction from your 'set point'); and if your 'set point' and weight are different (because you have gained weight since your 20s), that within a year you should have achieved at least a 10 per cent reduction in what your weight was at the start of the diet. (This will not, however, be a 10 per cent reduction in weight from your 'set point, which might take much more than a year to reach.)