hi mihir ,
well unhealthy weight loss is when you over do the diet part .. that is go on a very low cal diet , like less than 1000 cal a day .. or you get stuck with only one or 2 food items and avoid the rest completely. or if you over do on th exercise part and tire yourself out so much that you dont have the stamina to do anything else throughout the day. these methods are not only unhealthy but also temporary. according to the indian dietitic association and other nutritional constitutions, it is advicable to lose only around 1/2 kg of weight or so in a week.. this kind of a weight lioss is considered healthy and steady. as weight loss is reletated to causing relief from a lot of a health problems, it is good till you are feeling all fresh and energetic due to the loss. and positive from within. it gets unhealthy the moment you start feeling weak and worn out .. if you have been sticking to these ground rules and losing 4 kgs a month .. we are good with it .. but if you are going too over board with any of it and overdoing it to lose this kind of weight then it certainly is unhealthy ..