A key problem in all weight-loss programs to fight obesity is the extent to which the body weight is maintained on a long-term basis. The study examines whether the 1-year consumption of healthy Nordic foods can result in better sustainable weight control compared to a control diet.

After a successful 6-week VLCD period in obese subjects (n = 80, 52 ± 10y, BMI 34.4 ± 3.1 kg/m2, 69% female; 93% completers, -10.9 ± 3.0 kg, p < 0.001), the subjects were randomized to a new Nordic diet (NND) and a traditional Nordic diet (TND) group. The following 1-year period was a body weight maintenance period where the diets were implemented ad libitum. Weight, BMI, waist circumference and sagittal abdominal diameter were measured at 0 (immediately after VLCD), 6 and 12 months. Results are reported as mean ± SEM. Differences in the anthropometric parameters between the diets at different time points compared to the start of the dietary intervention were statistically evaluated using a general linear model (GLM-ANOVA, Minitab Inc.).

Forty-three subjects were randomized to NND and 37 to TND. In the NND group, 31 subjects completed the 6-month visit and 30 subjects 12-month visit. In the TND group, 24 and 21 completed 6-month and 12-month visit, respectively. We observed a non-significant difference in weight change at 6 months between NND (0.04 ± 0.87kg) and TND (2.65 ± 1.08kg). At 12 months, the weight change was significantly different between the diets (NND 1.94 ± 0.99 kg and TND 5.69 ± 1.41 kg, p = 0.029, R2 = 9.39). Change in the BMI at 12 months was significantly lower for NND (0.65 ± 0.33 kg/m2) compared to TND (1.87 ± 0.46 kg/m2, p = 0.034, R2 = 8.87) but not at 6 months (0.01 ± 0.30 kg/m2 for NND and 0.84 ± 0.36 kg/m2 for TND). Differences in waist circumference (at 6 months 0.26 ± 0.93 cm for NND and 3.30 ± 1.45 cm for TND; at 12 months 1.04 ± 1.01 cm for NND and 3.85 ± 1.79 cm for TND) were not statistically different. The sagittal abdominal diameter was borderline statistically different at 6 months (NND -0.28 ± 0.29 cm and TND 0.49 ± 0.22 cm, p = 0.049, R2 = 7.09) but not at 12 months (NND 0.41 ± 0.38 cm and TND 1.23 ± + 0.42cm).

Results show a tendency that the type of diet has an impact on successful weight maintenance, with a benefit for the NND. Further statistical analyses including dietary compliance and biomarkers are needed and will be performed. Moreover, the study is ongoing with a total of 2-year follow-up.