Do I have to eat all of my calorie allowance?

The short answer is no, if you are feeling genuinely satisfied on less calories and getting a balanced diet. Around 1,200 calories per day is fine, but we strongly advise against going below this.

To explain your targets

Around 1,400 cals a day is a sensible and sustainable calorie target if you are trying to lose weight. Trying to stick to a lower target is likely to result in failure as your diet will be much more restrictive and much harder to sustain. The secret of success is to keep going with a reduced calorie intake over a period of time – your goal is steady weight loss. We all want an overnight miracle, but this approach is far more likely to succeed – and importantly result in long term maintenance.

In fact your body's weight loss efficiency falls at a lower calorie level – in other words, the extra weight loss benefit of eating say 1,000 calories/day compared with eating 1,200 calories/day – is so small as to make the extra deprivation and hunger just not worth it.

Your daily target has been set to create the required calorie deficit for weight loss – so there is no need to feel like you should restrict yourself further in order to lose weight.