Introduction: Primary prevention of hypertension underlines the relevance of body composition abnormalities, particularly of so-called lean body mass. Increased fructose intake can lead to elevated blood pressure. Aim: The aim of this study was to assess the metabolic profile and dietary fructose intake in prehypertensive and hypertensive adolescents. Material and methods: Thirty-one patients (18 boys and 13 girls) aged 12–18 years (median: 15 years) with well controlled hypertension and prehypertension were selected for the study. The authors measured body height and weight, body mass index, waist-to-hip ratio, waist-to-height ratio as well as fat content and lean body mass using bioelectrical impedance analysis. The patients’ diet was assessed in terms of fructose intake and food energy value. Results: Forty-two per cent of children (33% of boys and 61% of girls) had abnormally high body mass index (BMI z-score > 2.0 SDS). The waist-to-height ratio was significantly higher in girls than in boys (0.53 and 0.45, respectively, p = 0.04). The results in waist circumference z-score were similar (2.82 vs. 1.13, respectively, p = 0.02). Girls had greater fat mass than boys (31% vs. 17%, respectively, p = 0.001). The energy value of girls’ diet was lower (1,967 vs. 2,683 kcal, p = 0.003), but excessive energy intake was observed in both groups (120% of requirement). Dietary fructose intake covered 11% of energy requirement. Conclusions: The study demonstrated that girls with elevated blood pressure have a greater amount fat tissue than boys and its distribution is more unfavourable. The diet of children with elevated blood pressure values is characterised by excessive energy delivery, and dietary fructose intake exceeds daily recommended intake of simple sugars.