People who want to lose weight successfully should drink at least two litres of fluids a day, said the Consumer Rights Protection Centre in the German state of Rhineland-Palatinate.
The centre said that many overweight people drank too little and often mistook thirst for hunger. According to Gewicht im Griff (Weight Under Control), a how-to manual promoted by the consumer centre and recently reprinted, fluids spur metabolism and also improve skin tone.
The body frequently has to "learn" thirst. People not used to drinking a lot of fluids have less of an urge to drink than those who drink fluids regularly. Keeping to a "drinking schedule" can ensure that the former reach for a glass of water more often.
For people who find water boring, alternatives are unsweetened herbal and fruit teas or mixtures of sparkling water and fruit juice. Consumption of coffee and black tea should be kept at moderate levels - no more than two to three cups a day.
Beer lovers need not fully strike the beverage from their evening diet, but beer is a poor thirst quencher and contains a lot of calories.