In Qur'an, Ramadaan is not used for a month but rather a category of 'Negatives of life' like 'Don'ts of life'. In human nature, the negative approaches such as self caring, non-factual, emotional, blind following, or thinking only of him/herself, family etc and not of collective life is where the problem is. With such approaches, it may not be devastating upfront, but collective human life suffers miserably when all is said and done. That's what was referred 'Ramadaan' as a category and was mentioned that Qur'an was brought forth for this category of approach since guidance is needed only where there are things that are not to be done. The objective was successful, progressive, bountiful, responsible, harmonious human life in this world.

Whenever, wherever you encounter that category, stay away (Saum) from it. If humans did not have that negatives in biological makeup, they would not need any guidance. So it was not any month of Ramadaan or fasting of food that Qur'an talked about. Its message was to address individual approach of life based on successful collective human life so that whatever we do in our individual capacity, it should be a very thought out approach based upon successful of collective human life. That's what is most difficult for human being.