I can give you my advice based on actual results and experience:
It will depend on your current weight, but if you have an entire month you could lose a LOT of weight. If you are, say, 11 stone and 5 feet 10 inches, losing 10 pounds should be very easy. Following a true (still very healthy) detox diet could see you lose well over 20 pounds. Shock Horror! But true. You needn't go to those lengths however.
Our lifestyles these days are so much less active than 50 years ago. Most of the logic that tells us to eat 3 square meals a day is from a very, very outdated era. I would be personally very happy to eat 3 square meals a day if my job involved running around all day on my feet (and I don't mean 'running' as a metaphor), or a very high degree of manual labour.
These days, most of us (me included) spend all day sitting down rather than moving around burning off fat. You ought to ask yourself, first of all, if the quantity you are eating each day is really required by your body. I doubt it. Most likely, you are addicted to eating at specific times of the day and in specific quantities due to a combination of boredom, greed, or cravings for specific tastes.
Many people in the West have almost no comprehension of the actual physical feeling of hunger anymore, since we have fully stocked fridges at all times! In order to physically feel hunger (and remember what the word actually means), try going all day without eating until, say, 8pm at night. You should start to feel a slightly sick feeling in your stomach. This is hunger.
The little you do eat should be very healthy. Eat less (possibly much less) and eat healthy, nutritious food. You will need to adjust your food intake according to your lifestyle, but to give you an idea, take the following scenario:
I spend all day working on a computer, and I never exercise. In order to maintain optimum health I eat just one medium-sized meal a day (a bowl of pasta, some pitta break on the side, a glass of juice), sometimes a little more if I think I *need* it. Not only am I physically significantly healthier than my friends (and more toned, slim and much more muscular physique), I am also able to perform any physcial activity such as soccer or tennis, with far greater endurance than them, on the rare occasions (once or twice a year) when I am coaxed into taking part.
Another plus = I never get tired (my body is not wasting energy digesting endless food). I find I need just 5 or 6 hours sleep a night max. I wake early (6 or 7 am) and go to bed late (1 or 2 am)
Hope some of this helps. There will be many conflicting answers to your question. Mine is, I like to feel, hardcore realist. It is very popular these days to have a politically correct attitude to such things however

For this reason I would expect my post to be flamed.