A weight management system comprising: - a cash register system, a user client and a weight management module, coupled via a wide area network, and - a personal card with a code, the code identifying a user to the cash register system and being related to a user ID, - the cash register system being arranged for automatically sending, when the user pays for a food item, corresponding food intake information and the user ID to the weight management module, - the weight management module comprising: - a food information system for storing a respective calorie content for a plurality of food items, - a calorie intake component, coupled to the food information system, for calculating an amount of calories taken by the user based on the received food intake information, - a calorie balance component, coupled to the calorie intake component, for calculating a calorie balance for the user, based on the amount of calories taken by the user, - the user client being arranged for obtaining the calorie balance from the weight management module and comprising output means for providing the calorie balance to the user, characterised in that the user client is coupled to a weight scale configured to provide user weight, wherein the calorie balance component is further configured to compare the user weight with the calorie balance and to provide feedback to the user based on the comparison. - a cash register system, a user client and a weight management module, coupled via a wide area network, and - a personal card with a code, the code identifying a user to the cash register system and being related to a user ID, - the cash register system being arranged for automatically sending, when the user pays for a food item, corresponding food intake information and the user ID to the weight management module, - the weight management module comprising: - a food information system for storing a respective calorie content for a plurality of food items, - a calorie intake component, coupled to the food information system, for calculating an amount of calories taken by the user based on the received food intake information, - a calorie balance component, coupled to the calorie intake component, for calculating a calorie balance for the user, based on the amount of calories taken by the user, - the user client being arranged for obtaining the calorie balance from the weight management module and comprising output means for providing the calorie balance to the user, characterised in that the user client is coupled to a weight scale configured to provide user weight, wherein the calorie balance component is further configured to compare the user weight with the calorie balance and to provide feedback to the user based on the comparison. - a food information system for storing a respective calorie content for a plurality of food items, - a calorie intake component, coupled to the food information system, for calculating an amount of calories taken by the user based on the received food intake information, - a calorie balance component, coupled to the calorie intake component, for calculating a calorie balance for the user, based on the amount of calories taken by the user, - the user client being arranged for obtaining the calorie balance from the weight management module and comprising output means for providing the calorie balance to the user, characterised in that the user client is coupled to a weight scale configured to provide user weight, wherein the calorie balance component is further configured to compare the user weight with the calorie balance and to provide feedback to the user based on the comparison.