Three month combining diet is the most used diet for loosing body weight. The basis of this diet is macronutrient separation within the each day. The diet consists of four day types (protein day, fruit day, starch day, carbohydrate day). In our study this diet was nutritionally evaluated with estimation intake method and computer based nutritional programme Prodi 5.7. Data were compared with the recommended values for nutrient intake. Results showed that estimated average daily energy intake (4196+-1483 kJ) does not achieve the basal metabolic rate of an average woman nor average man. Macronutrient intake in terms of energy caloric profile according to day type was not satisfactory but on average macronutrient energy ratio meets the recommendation. Protein intake was the highest on protein day whereas carbohydrate intake was the highest on carbohzdrate day, as according to our expectations. Fat intake was low, on average 23% of daily energy intake. Three month combining diet is very low energy diet for this reason weight lost is assured. On average this diet does not meet the recommended values for total dietary fibre, vitamin B1, B2, biotin, folic acid, vitamin A, D, E and minerals calcium, magnesium and iodine. Due to nutrient deficiency this diet can lead to health problems, therefore long-term usage is not recommended.