Calculated vs analysed nutrient composition of weight reduction diets

The aim of the study was to compare calculated values with analysed values of some nutrients in weight reduction diets. Ten obese adults were instructed to follow a balanced low-energy diet (5.0 MJ/1200 kcal per day) for 6 months. They were asked to collect samples of all food and beverages they consumed on 3 consecutive days in two phases. During these days, the subjects filled in food records. In addition, samples of a low-energy model diet were collected. The following nutrients were analysed: protein, fat, fatty acids, dietary fibre, calcium, magnesium, iron, zinc, copper, selenium, manganese, molybdenum, sodium, potassium, cadmium and lead. The composition of the diets was calculated from food records by using the Nutrica computer program. Fifteen food samples were included in the final analysis. For most nutrients, calculated values were higher than the analysed ones. Results of our study suggest that the calculation method using food records and the current Finnish database can provide: (1) a reasonably good estimation for the intake of protein, fat, fatty acids, dietary fibre, calcium, magnesium, potassium and manganese; (2) a moderate or uncertain estimation for the intake of iron, sodium, zinc and selenium; and (3) a poor estimation for the intake of copper, molybdenum, cadmium and lead.