Not all calories are equal

While the number of calories in compared to the number of calories out is important, so to is the source of those calories and their ratios.

It is also important to consider what proportion of the calories you ingest come from protein, carbohydrates and fats.

The quality of the food is also a consideration. There can be plenty of calories but a serious deficiency in quality nutrients.

There's no hard and fast 'these-figures-fit-all' answer when it comes to calories. Basically though the best way to lose weight is to increase activity rather than constrict calories. The calories consumed from fats could easily be cut and replaced by calories from better sources.

Find out how many calories you need for your ideal weight and lifestyle and that's your benchmark. If you want to reduce simply exercise more. If you want to build up, exercise more (with weights) and increase your quality calories.

That's about as simple as I can make it, though when you go into it in depth it can be quite complex.