Determinants of adherence to a high-protein and high-unsaturated fatty acids dietary intervention: 1-year results of the NutriAct randomized controlled multi-center trial

Background NutriAct is a 36-month randomized controlled multi-center trial designed to assess the effects of a high-protein and high-unsaturated fatty acids (UFA) food pattern on healthy aging. We aimed to determine assess determinants of a successful modulation of dietary pattern after 12 months. Methods: 502 participants were randomized into control group including dietary recommendations of the German Nutrition Society or to intervention group, where a food pattern based on high intake of predominantly plant proteins, UFA and fiber (NutriAct pattern) was implemented. Food intake was assessed by 3-day food records at months 0, 3, 6 and 12. Weight loss was not aimed. Results: Participants with complete food records at baseline were included (242 intervention, 246 control (median age 66y, 37% males)). At baseline, BMI was related to higher protein and saturated fatty acids and lower fiber intake. The intervention resulted in higher intake of protein, mono- and polyunsaturated fatty acids (MUFA, PUFA) and fiber, and lower carbohydrate and saturated fatty acid consumption (p < 0.001). While individuals already at baseline closer to the NutriAct pattern also achieved a diet closer to the proposed pattern at month 12, the strongest changes of dietary behavior were seen in those with dietary patterns further away from the proposed pattern at baseline. Attendance to nutritional sessions was crucial to change PUFA, MUFA, fiber and carbohydrate intake. Conclusions: A successfully modification of dietary pattern was achieved by the intervention within 12 months. Baseline diet and attendance to nutritional sessions were substantial determinants predicting these changes.