After summer holidays, miracle-diet adherents stick to these diets to lose the weight gained in the last months in record time. Gyms also become overcrowded with people making a final sprint of sacrifice whose results do not exactly match previous expectations and with few benefits for health. In the field of nutrition, miracles do not exist: in the same way we gain weight as years pass by, weight loss should be equally progressive, states Professor Emilio Martínez de Victoria Muñoz, Head of the Institute of Nutrition and Food Technology (http://www.ugr.es/~winyta/) at the University of Granada (Universidad de Granada) in Spain. Energy balance It becomes clear that the energy needed by the body to carry out its functions comes essentially from food. Nevertheless, a whole range of hormonal and nervous mechanisms take part in body weight regulation, which makes such process a bit more complex. When the amount of consumed calories is similar to that of calories used during the day, the energy balance is kept stable and, therefore, weight is kept constant. However, when consumed calories exceed used calories this balance is disturbed and weight is gained, as excess calories are stored as fat in the body. As an example, Professor Martínez de Victoria points out that an energetically-balanced girl who is given a chocolate cookie a day during four years will gain 20 lbs (approximately 9 kg) in that time. Easy lost, easy back The researcher affirms that miracle diets are useless to get a stable negative energy balance. There are no scientific foundations behind the vast majority of these diets and they usually restrict consumption of certain food groups, which entails nutrient deficiency whose consequences are serious health problems. In addition to this, miracle diets only help to lose weight in the form of glycogen and water – not fat – that being the reason why rapidly lost pounds are immediately recovered. Among those panacea diets, and absolutely ignoring all medical recommendations on what a healthy diet should be like, consumers will come across the South Beach diet, a revolutionary plan that allows you to eat as much as you wish while assuring that to lose weight you will have to undergo a two-week purifying period based upon the elimination of sugar and simple carbohydrates. Atkins nutritional method is another example: with this diet you can eat unlimited amounts of fats – such as butter – as well as of meat, fish, eggs and dairy products, whilst restricting vegetables and fruit. These are only two of the endless list of miracle diets, in which the Artichoke diet or the Blood Type diet also occupy leading positions. Keeping weight under control Prof. Martínez de Victoria insists that the best way to control body weight is to combine a limited food intake with regular physical exercise. In this sense, he states that with a 500 to 700 calorie deficit, depending on body weight, age and physical exercise, a person can gradually lose 6.5 lbs a month, with the guarantee of not recovering double the weight they lost in half the time they lost it. In the same way, this researcher stresses the fact that a high-fibre diet helps control obesity, as fibre-rich foods facilitate a lower intake because their mastication time is longer and, due to their volume, produce the filling sensation more quickly. Furthermore, fibre speeds intestinal transit time while slowing food absorption. All these data have been recently presented in the University of Granada’s http://www.ugr.es summer course Healthy Food and Physical Activity (Alimentación Saludable y Actividad Física), organised by the UGR’s Centro Mediterráneo http://www.ugr.es/~cm/.