2.10. Statistical Analysis
The obtained data were analyzed using the methods specified in the statistical analysis plan prepared prior to the start of the study. The nutrient intake levels were presented as mean ± standard deviation for pre-intervention (week 0) and post-intervention (weeks 4, 8, and 12) calculated values. In addition, measurements of body composition, muscle strength, and TUG were taken, calculating the changes from pre-intervention (week 0) as the reference to post-intervention (weeks 4, 8, and 12), and the values were presented as mean ± standard deviation.Nutritional intake during the intervention period was subjected to multiple comparisons to compare the control and test diet groups. First, the presence or absence of homogeneity of variance was confirmed for each data using Levene’s test, then Steel’s test was conducted if significance was found, and Dunnett’s test was used if it was not significant.For other measured variables, first, multiple comparisons were conducted among the four groups for the value at week 0 of intake. If no significant differences were found, a linear mixed-effects model was utilized (with fixed effects for diet and time of measurement, and a random intercept for subjects) to examine the interaction between diet effects and time effects for the repeated measurements. If no interaction effect was observed, a linear mixed-effects model equation without the interaction term was used to confirm the presence of diet effects for the repeated measurements (weeks 4, 8, and 12). If diet effects were detected, multiple comparisons were conducted among the four groups at each time point (weeks 4, 8, and 12). If an interaction effect was observed, a one-way analysis of variance (ANOVA) was performed to confirm the diet effects, and if significant differences were found, multiple comparisons among the four groups at each time point (weeks 4, 8, and 12) were conducted. The multiple comparisons among the four groups were tested using Levene’s test for homogeneity of variance, and if significance was observed, Steel’s test was employed for testing, while Dunnett’s test was used when significance was not observed.For within-group comparisons between the data at week 0 and the data at weeks 4, 8, and 12 of test food intake, multiple comparisons were conducted using Levene’s test to assess homogeneity of variance. If significance was observed, Steel’s test was employed for testing, while Dunnett’s test was used when significance was not observed.The basic statistics of the analyzed data were calculated using Microsoft Excel for Office365 MSO (Microsoft Japan Corporation, Tokyo, Japan), and statistical processing was performed using R statistical software v4.1.0 for Windows (R Core Team, Vienna, Austria). In all significance analyses, a significance level below 5% was considered statistically significant, while a level between 5% and less than 10% was considered as a trend.