Obesity is the most common disease of affluence of the XXI century. According to WHO (World Health Organization), it is defined as a chronic metabolic disorder manifested by excessive accumulation of adipose tissue with high tendency for familial occurrence. According to WHO, obesity reaches epidemic proportions in many countries. High BMI (Body Mass Index) correlates with coexisting diseases. Traditional dietetic treatment often does not bring any results. A form of conservative (non-surgical) support for patients in fighting with obesity is the reduction of stomach volume by bioenteric intragastric balloon (BIB) treatment. The aim of the work was to develop a diet with anti-inflammatory properties, well-tolerated by the patients after BIB treatment. An American diet was modified by changing the composition of fatty acids, increasing anti-oxidative potential and adding synbiotics for patients treated with BIB. Chemical analysis of reconstructed food ratios of recommended diet was performed, analysing the content of micronutrients, composition of fatty acids, antioxidative capacity, reducing power and the content of polyphenols. Improvement in anthropometric measurement results and satisfying body weight loss were obtained, while preserving fat-free body mass. Improvement in the parameters of lipid metabolism was also observed, that is, decrease in total CH (cholesterol) and TG (triglycerides), and normalized concentration of HDL (high density lipoproteins) and LDL (low density lipoproteins) fractions. Reduced concentration of glucose in blood and lower blood pressure was also noted. Performed study confirms the effectiveness of complex treatment with BIB and properly adjusted individualized diet. Observations and own experience allow to deduce that patients who resign from systematic contact with a dietician cannot maintain reduced body weight. Abandoning previous habits is the only way to maintain the effect of weight loss. Most importantly, the change in patients’ awareness and consequent behaviour in the future are crucial. Even though genes may contribute to obesity, environmental factors mainly determine the possibility of the disease to occur. Therefore, the change of patients’ lifestyle after body weight reduction will decide on their fate.