**Table 3.** Primary outcome weight pre and post intervention.


Values are presented as the mean ± SD. *n* = number of participants. *p* value obtained from a two-way mixed ANOVA test on pre and post data only. \*denotes significant difference from baseline, *p* < 0.05.



The main effect of group showed a substantial statistically significant difference in diastolic blood pressure between the intervention groups, F(1, 44) = 4.524, *p* = 0.039, partial η<sup>2</sup>

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**Figure 2.** Individual response to weight change for participants completing pre and post measures **Figure 2.** Individual response to weight change for participants completing pre and post measures in the mRMR (*n* = 24) and eRMR groups (*n* = 23). that blood glucose was significantly lower at week 12 (−0.3 mmol/L, *p* = 0.004) compared to baseline (5.2 mmol/L, SE 0.12) (Figure 3).

**mRMR Group (n = 24) eRMR Group (n = 23)**

tration over time, F(1, 43) = 9.120, *p* < 0.0005, partial η2 = 0.175. Post hoc analysis revealed

r = 0.00. There was no significant interaction between the intervention and time on HC (Table 2), F(1, 44) = 0.010, *p* = 0.921, partial η2 = 0.000. The main effect of group showed **Figure 3.** Blood glucose (mmol/L) measured at baseline and week 12 for the mRMR (*n* = 23) and eRMR groups (*n* = 22).*3.13. Total Cholesterol*  **Figure 3.** Blood glucose (mmol/L) measured at baseline and week 12 for the mRMR (*n* = 23) and eRMR groups (*n* = 22).

(*p* = 0.001) at week 12 (−8.4 cm) compared to baseline (117.1 cm, SE = 2.1).

= 112.25, *n* = 28) and eRMR participants (Md = 113.00, *n* = 25), U = 351, z = 0.027, *p* = 0.979,

that there were no statistically significant differences in HC between the intervention

There was a significant difference in baseline total cholesterol between mRMR (Table

*p* < 0.0005, partial η2 = 0.32. Post hoc analysis revealed that HC was significantly reduced

0.017, r = 0.34. There was no significant interaction between the intervention and time on total cholesterol concentration (Table 4), F(1, 41) = 0.584, *p* = 0.449, partial η2 = 0.014. The

*3.7. Waist to Hip Ratio* 

partial η2 = 0.000 (Figure 4).

main effect of group showed no significant difference in total cholesterol between the intervention groups, F(1, 41) = 1.836, *p* = 0.183, partial η2 = 0.043. The main effect of time showed no significant difference in total cholesterol over time, F(1, 41) = 0.011, *p* = 0.918,

**Figure 4.** Total cholesterol (mmol/L) measured at baseline and week 12 for the mRMR (*n* = 23) and eRMR groups (*n* = 20).*3.14. High-Density Lipoprotein*  **Figure 4.** Total cholesterol (mmol/L) measured at baseline and week 12 for the mRMR (*n* = 23) and eRMR groups (*n* = 20).

*Nutrients* **2021**, *13*, x FOR PEER REVIEW 16 of 26

**Figure 5.** High-density lipoprotein (mmol/L) measured at baseline and week 12 for the mRMR (*n* = 23) and eRMR groups (*n* = 20).*3.15. Total Cholesterol to High-Density Lipoprotein Ratio*  **Figure 5.** High-density lipoprotein (mmol/L) measured at baseline and week 12 for the mRMR (*n* = 23) and eRMR groups (*n* = 20).

There were no significant differences in baseline TC:HDL (Table 1) between mRMR

on TC:HDL (Table 4), F(1, 40) = 0.028, *p* = 0.869, partial η2 = 0.001. The main effect of group showed no significant difference in TC:HDL between the intervention groups, F(1, 40) = 3.383, *p* = 0.073, partial η2 = 0.078. The main effect of time showed no significant difference in TC:HDL over time (Table 2), F(1, 40) = 3.043, *p* = 0.089, partial η2 = 0.071 (Figure 6).

**Figure 6.** Total cholesterol to high-density lipoprotein ratio calculated at baseline and week 12 in

**mRMR Group (n = 23) eRMR Group (n = 19)**

**Baseline Week 12**

**Time**

both the mRMR (*n* = 23) and estimated eRMR groups (*n* = 19) groups.*3.16. Low-Density* 

*Lipoprotein* 

**0.0**

**1.0**

**2.0**

**3.0**

**TC:HDL**

**4.0**

**5.0**

**0.0**

**0.5**

**1.0**

**HDL (mmol/L)**

**1.5**

**2.0**

**Figure 5.** High-density lipoprotein (mmol/L) measured at baseline and week 12 for the mRMR (*n* =

**Baseline Week 12**

**Time**

**eRMR Group**

**(n = 21)**

There were no significant differences in baseline TC:HDL (Table 1) between mRMR (Md = 3.4, *n* = 28) and eRMR participants (Md = 3.0, *n* = 21), U = 206, z = −1.771, *p* = 0.077, r = 0.25. There was no statistically significant interaction between the intervention and time on TC:HDL (Table 4), F(1, 40) = 0.028, *p* = 0.869, partial η2 = 0.001. The main effect of group showed no significant difference in TC:HDL between the intervention groups, F(1, 40) = 3.383, *p* = 0.073, partial η2 = 0.078. The main effect of time showed no significant difference in TC:HDL over time (Table 2), F(1, 40) = 3.043, *p* = 0.089, partial η2 = 0.071 (Figure 6).

23) and eRMR groups (*n* = 20).*3.15. Total Cholesterol to High-Density Lipoprotein Ratio* 

**mRMR Group**

**(n = 23)**

**Figure 6.** Total cholesterol to high-density lipoprotein ratio calculated at baseline and week 12 in both the mRMR (*n* = 23) and estimated eRMR groups (*n* = 19) groups.*3.16. Low-Density*  **Figure 6.** Total cholesterol to high-density lipoprotein ratio calculated at baseline and week 12 in both the mRMR (*n* = 23) and estimated eRMR groups (*n* = 19) groups. mmol/L, *p* = 0.021). The main effect of time showed no statistically significant difference in LDL over time, F(1, 34) = 0.642, *p* = 0.429, partial η2 = 0.019 (Figure 7).

**Figure 7.** Low-density lipoprotein (mmol/L) calculated at baseline and week 12 for the mRMR (*n* = 19) and eRMR groups (*n* = 17).*3.17. Triglycerides*  **Figure 7.** Low-density lipoprotein (mmol/L) calculated at baseline and week 12 for the mRMR (*n* = 19) and eRMR groups (*n* = 17).

There were no significant differences in baseline triglycerides (Table 1) between mRMR (Md = 1.08, *n* = 25) and eRMR participants (Md = 1.19, *n* = 19), U = 278, z = 0.960, *p*

main effect of group showed no significant difference in triglyceride concentration between the intervention groups F(1, 36) = 0.242, *p* = 0.626, partial η2 = 0.007. The main effect of time showed no significant difference in triglyceride concentration over time, F(1, 36) =

2.028, *p* = 0.163, partial η2 = 0.053, (Figure 8).

**Figure 8.** Triglycerides (mmol/L) measured at baseline and week 12 for the mRMR (*n* = 20) and eRMR groups (*n* = 18).*3.18. Energy Intake*  **Figure 8.** Triglycerides (mmol/L) measured at baseline and week 12 for the mRMR (*n* = 20) and eRMR groups (*n* = 18).

0.249, *p* = 0.804, r = 0.04. There was no significant interaction between the intervention

There were no significant differences in baseline energy intake (Table 1) of mRMR **Table 5.** Metabolic outcomes and estimated energy intake for groups across the intervention period.


*3.19. Measured Resting Metabolic Rate*  There were no significant differences in baseline measured RMR (Table 1) between mRMR (Md = 1604.00, *n* = 29) and eRMR participants (Md = 1691.00, *n* = 23), U = 347, z = Values are presented as the mean ± SD. *n* = number of participants with complete data set available for each variable. *p* value obtained from a two-way mixed ANOVA test. \* denotes significant difference, *p* < 0.05. mRMR, measured resting metabolic rate; RER, respiratory exchange ratio; eRMR, estimated resting metabolic rate (Mifflin-St. Jeor equation); eEI, estimated energy intake (group analysis from a 3-day food diary).

> groups and time on measured RMR (Table 5), F(2.421, 87.171) = 0.284, *p* = 0.794, partial η<sup>2</sup> **Table 6.** Estimated energy intake at baseline and week 12 for male and female participants.


*3.20. Respiratory Exchange Ratio*  Values are presented as the mean ± SD. *n* = number of participants with complete data available at each time point. eEI, estimated energy intake (from a a3 day food diary) for male and female participants.

There were no significant differences in baseline measured RER (Table 1) between **Table 7.** Prescribed energy intake versus estimated energy intake at week 12 for male and female participants.


showed no significant difference in RER over time, F(2.339, 84.206) = 1.159, *p* = 0.324, partial η2 = 0.031. Values are presented as the mean ± standard deviation. *n* = number of participants with complete data set available at each time point. Estimated 12-week daily average energy intake from a 3-day food diaries.

*3.21. Predicted Resting Metabolic Rate* 

#### *3.3. Individual Response to Weight*

A total of 37.5% of participants in the mRMR group and 39.1% of participants in the eRMR group reduced between 0.1 and 2.9% of initial body weight. A weight reduction between 3 and 4.9% was observed in 20.8% and 13% of participants in the mRMR and eRMR groups, respectively. A 5–9.9% reduction from initial body weight was observed in 16.7% and 13% of participants in the mRMR and eRMR groups, respectively. Of the participants in the eRMR, 4.3% experienced a 10–14.9% weight reduction. Of the participants in the mRMR 4.2% experienced a weight reduction of ≥15%. Overall, 20.8% mRMR and 17.4% of eRMR participants experienced clinically meaningful (i.e., ≥5% of initial weight) weight reduction. Weight gain of ≤2% was observed in 20.8% and 30.4% of participants in the mRMR and eRMR groups, respectively (Figure 2).

#### *3.4. Body Mass Index*

There were no significant differences between groups for baseline BMI (Table 1) of mRMR (Md = 106.00, *n* = 28) and eRMR (Md = 112.50, *n* = 25), U = 417, z = 1.194, *p* = 0.232, r = 0.16. There was no significant interaction between the intervention and time on BMI (Table 2), F(1, 45) = 0.335, *p* = 0.566, partial η <sup>2</sup> = 0.007. There was no significant effect for group, when comparing BMI, F(1, 45) = 0.394, *p* = 0.534, partial η <sup>2</sup> = 0.009. The main effect of time showed a statistically significant difference in BMI, across time points, F(1, 45) = 25.801, *p* < 0.0005, partial η <sup>2</sup> = 0.364. Post hoc analysis revealed that BMI was significantly reduced (*p* = 0.001) at week 12 (29.9 kg/m<sup>2</sup> , SE = 0.7) compared to baseline (30.74 kg/m<sup>2</sup> , SE = 7.0).

#### *3.5. Waist Circumference*

There were no significant differences for WC at baseline (Table 1) between mRMR (Md = 29.30, *n* = 29) and eRMR participants (Md = 29.46, *n* = 25), U = 387, z = 0.43, *p* = 0.67, r = 0.06. There was no significant interaction (intervention x time) for WC (Table 2), F(1, 44) = 1.57, *p* = 0.22, partial η <sup>2</sup> = 0.03. The main effect of group showed that there was no statistically significant difference in WC between the intervention groups, F(1, 44) = 2.77, *p* = 0.10, partial η <sup>2</sup> = 0.06. The main effect of time showed a statistically significant difference in WC over time, F(1, 44) = 58.083, *p* < 0.0005, partial η <sup>2</sup> = 0.569. Post hoc analysis revealed that WC was significantly reduced (*p* = 0.001) at week 12 (−9.3 cm) compared to baseline (111.1 cm SE = 1.9).

#### *3.6. Hip Circumference*

There was no significant difference in HC at baseline (Table 1) between mRMR (Md = 112.25, *n* = 28) and eRMR participants (Md = 113.00, *n* = 25), U = 351, z = 0.027, *p* = 0.979, r = 0.00. There was no significant interaction between the intervention and time on HC (Table 2), F(1, 44) = 0.010, *p* = 0.921, partial η <sup>2</sup> = 0.000. The main effect of group showed that there were no statistically significant differences in HC between the intervention groups (Table 2), F(1, 44) = 0.000, *p* = 0.99, partial η <sup>2</sup> = 0.000. The main effect of time showed a substantial statistically significant difference in HC over time (Table 2), F(1, 44) = 20.586, *p* < 0.0005, partial η <sup>2</sup> = 0.32. Post hoc analysis revealed that HC was significantly reduced (*p* = 0.001) at week 12 (−8.4 cm) compared to baseline (117.1 cm, SE = 2.1).

#### *3.7. Waist to Hip Ratio*

There were no significant differences in WHR between mRMR (0.93 ± 0.077) and eRMR groups (0.96 ± 0.082; t(51) = −1.479, *p* = 0.145) at baseline (Table 1). There was no significant interaction between the intervention and time on WHR (Table 2), F(1, 44) = 2.528, *p* = 0.119, partial η <sup>2</sup> = 0.054. The main effect of group showed a substantial significant difference in WHR between the intervention groups, F(1, 44) = 5.751, *p* = 0.02, partial η <sup>2</sup> = 0.12. The main effect of time showed a substantial statistically significant difference in WHR at the different time points, F(1, 44) = 4.085, *p* = 0.049, partial η <sup>2</sup> = 0.09. Post hoc

analysis revealed that WHR was significantly reduced (*p* = 0.049) at week 12 (0.9 SE = 0.01) compared to baseline (1.0 SE = 0.01).

#### *3.8. Percent Body Fat*

There were no significant differences in baseline body fat percent (Table 1) between mRMR group (37.53 ± 8.57) and eRMR groups (35.72 ± 7.53; t(52) = 0.818, *p* = 0.417). There was no significant interaction between the intervention groups and time on body fat (Table 2), F(1.785, 66.044) = 0.705, *p* = 0.482, partial η <sup>2</sup> = 0.019. The main effect of group showed that there was no significant difference in body fat between the intervention groups, F(1, 37) = 0.084, *p* = 0.773, partial η <sup>2</sup> = 0.002. The main effect of time showed no significant difference in body fat over time, F(1.785, 66.044) = 2.259, *p* = 0.118, partial η <sup>2</sup> = 0.058.

#### *3.9. Muscle Mass*

There were no significant differences in baseline muscle mass (Table 1) between mRMR (Md = 49.10, *n* = 29) and eRMR participants (Md = 59.60, *n* = 25), U = 433, z = 1.22, *p* = 0.221, r = 0.17. There was no significant interaction between the intervention groups and time on muscle mass (Table 2), F(1.980, 73.275) = 1.017, *p* = 0.366, partial η <sup>2</sup> = 0.027. The main effect of group showed that there was no significant difference in muscle mass between the intervention groups, F(1, 37) = 0.846, *p* = 0.36, partial η <sup>2</sup> = 0.02. The main effect of time showed a substantial significant difference in muscle mass over time, F(1.980, 73.275) = 6.227, *p* < 0.0005, partial η <sup>2</sup> = 0.14. Post hoc analysis revealed that muscle mass was significantly reduced (both < *p* = 0.035) at week 3 (0.8 kg) and week 12 (2.1 kg) compared to baseline (55.6 kg, SE = 2.0). Post hoc analysis revealed no significant difference between muscles mass at week 6 and week 12 versus week 3 (both > *p* = 0.65). Post hoc analysis revealed no significant difference between muscle mass at week 6 versus week 12 (0.1%, *p*= 0.21).

#### *3.10. Systolic Blood Pressure*

There was a significant difference in systolic blood pressure at baseline (Table 1) between mRMR (Md = 126.00, *n* = 29) and eRMR participants (Md = 135.00, *n* = 25), U = 481, z = 2.065, *p* = 0.039, r = 0.28. There was no significant interaction between the intervention and time on systolic blood pressure (Table 2), F(1, 44) = 1.124, *p* = 0.295, partial η <sup>2</sup> = 0.025. The main effect of group showed a substantial significant difference in systolic blood pressure between the intervention groups, F(1, 44) = 6.654, *p* = 0.013, partial η <sup>2</sup> = 0.13. Post hoc analysis revealed systolic blood pressure was significantly lower in the mRMR group when compared to the eRMR group (−11.71 mmHg, *p* = 0.01). The main effect of time showed a significant difference in systolic blood pressure over time, F(1, 44) = 6.305, *p* < 0.0005, partial η <sup>2</sup> = 0.13. Post hoc analysis revealed that systolic blood pressure was significantly reduced at week 12 (−4.9 mmHg, *p* = 0.02) compared to baseline (130 mmHg, SE = 2.7).

#### *3.11. Diastolic Blood Pressure*

There were no significant differences in baseline diastolic blood pressure (Table 1) between mRMR (Md = 83.00, *n* = 29) and eRMR participants (Md = 87.00, *n* = 25), U = 457, z = 1.65, *p* = 0.099, r = 0.22. There was no significant interaction between the intervention and time on diastolic blood pressure (Table 2), F(1, 44) = 0.022, *p* = 0.884, partial η <sup>2</sup> = 0.000. The main effect of group showed a substantial statistically significant difference in diastolic blood pressure between the intervention groups, F(1, 44) = 4.524, *p* = 0.039, partial η <sup>2</sup> = 0.093. Post hoc analysis revealed that diastolic blood pressure was significantly lower in the eRMR group when compared to mRMR (−5.7 mmHg, *p* = 0.04). The main effect of time showed a significant difference in diastolic blood pressure over time, F(1, 44) = 5.444, *p* < 0.0005, partial η <sup>2</sup> = 0.110. Post hoc analysis revealed diastolic blood pressure was significantly reduced at week 12 (−3.1 mmHg, *p* = 0.02) compared to baseline (83.96 mmHg, SE 1.6).

#### *3.12. Blood Glucose*

There were no significant differences in baseline blood glucose (Table 1) between mRMR (Md = 4.85, *n* = 28) and eRMR participants (Md = 5.30, *n* = 25), U = 392, z = 0.749, *p* = 0.454, r = 0.10. There was no statistically significant interaction between the intervention and time on blood glucose concentration (Table 4), F(1, 43) = 0.112, *p* = 0.739, partial η <sup>2</sup> = 0.003. The main effect of group showed no significant difference in blood glucose concentration between the intervention groups, F(1, 43) = 3.203, *p* = 0.081, partial η <sup>2</sup> = 0.069. The main effect of time showed a statistically significant difference in blood glucose concentration over time, F(1, 43) = 9.120, *p* < 0.0005, partial η <sup>2</sup> = 0.175. Post hoc analysis revealed that blood glucose was significantly lower at week 12 (−0.3 mmol/L, *p* = 0.004) compared to baseline (5.2 mmol/L, SE 0.12) (Figure 3).

#### *3.13. Total Cholesterol*

There was a significant difference in baseline total cholesterol between mRMR (Table 1) (Md = 4.74, *n* = 28) and eRMR participants (Md = 3.935, *n* = 22), U = 186, z = −2.385, *p* = 0.017, r = 0.34. There was no significant interaction between the intervention and time on total cholesterol concentration (Table 4), F(1, 41) = 0.584, *p* = 0.449, partial η <sup>2</sup> = 0.014. The main effect of group showed no significant difference in total cholesterol between the intervention groups, F(1, 41) = 1.836, *p* = 0.183, partial η <sup>2</sup> = 0.043. The main effect of time showed no significant difference in total cholesterol over time, F(1, 41) = 0.011, *p* = 0.918, partial η <sup>2</sup> = 0.000 (Figure 4).

#### *3.14. High-Density Lipoprotein*

There were no significant differences in baseline HDL (Table 1) between mRMR (Md = 1.34, *n* = 28) and eRMR participants (Md = 1.23, *n* = 23), U = 306, z = −0.303, *p* = 0.762, r = −0.04. There was no statistically significant interaction between the intervention and time on HDL (Table 4), F(1, 42) = 2.196, *p* = 0.146, partial η <sup>2</sup> = 0.050. The main effect of group showed that there was no significant difference in HDL (Figure 5) between the intervention groups F(1, 42) = 0.014, *p* = 0.908, partial η <sup>2</sup> = 0.000. The main effect of time showed a significant difference in HDL concentration over time, F(1, 42) = 4.659, *p* < 0.0005, partial η <sup>2</sup> = 0.100. Post hoc analysis revealed that HDL was significantly lower at week 12 (−0.1 mmol/L, *p* = 0.04) compared to baseline (1.4 mmol/L, SE 0.1).

#### *3.15. Total Cholesterol to High-Density Lipoprotein Ratio*

There were no significant differences in baseline TC:HDL (Table 1) between mRMR (Md = 3.4, *n* = 28) and eRMR participants (Md = 3.0, *n* = 21), U = 206, z = −1.771, *p* = 0.077, r = 0.25. There was no statistically significant interaction between the intervention and time on TC:HDL (Table 4), F(1, 40) = 0.028, *p* = 0.869, partial η <sup>2</sup> = 0.001. The main effect of group showed no significant difference in TC:HDL between the intervention groups, F(1, 40) = 3.383, *p* = 0.073, partial η <sup>2</sup> = 0.078. The main effect of time showed no significant difference in TC:HDL over time (Table 2), F(1, 40) = 3.043, *p* = 0.089, partial η <sup>2</sup> = 0.071 (Figure 6).

#### *3.16. Low-Density Lipoprotein*

There was a significant difference in baseline LDL (Table 1) between mRMR (Md = 2.77, *n* = 24) and eRMR participants (Md = 2.21, *n* = 19), U = 104, z = −3.033, *p* = 0.002, r = 0.50. There was no statistically significant interaction between the intervention and time on LDL (Table 4), F(1, 34) = 1.194, *p* = 0.282, partial η <sup>2</sup> = 0.034. The main effect of group showed that there was a substantial statistically significant difference LDL between the intervention groups, F(1, 34) = 5.864, *p* = 0.021, partial η <sup>2</sup> = 0.15. Post hoc analysis revealed that LDL was significantly lower in the eRMR group than the mRMR group (–.491 mmol/L, *p* = 0.021). The main effect of time showed no statistically significant difference in LDL over time, F(1, 34) = 0.642, *p* = 0.429, partial η <sup>2</sup> = 0.019 (Figure 7).

#### *3.17. Triglycerides*

There were no significant differences in baseline triglycerides (Table 1) between mRMR (Md = 1.08, *n* = 25) and eRMR participants (Md = 1.19, *n* = 19), U = 278, z = 0.960, *p* = 0.337, r = 0.14. There was no significant interaction between the intervention and time on triglyceride concentration, F(1, 36) = 0.186, *p* = 0.669, partial η <sup>2</sup> = 0.005 (Table 4). The main effect of group showed no significant difference in triglyceride concentration between the intervention groups F(1, 36) = 0.242, *p* = 0.626, partial η <sup>2</sup> = 0.007. The main effect of time showed no significant difference in triglyceride concentration over time, F(1, 36) = 2.028, *p* = 0.163, partial η <sup>2</sup> = 0.053, (Figure 8).

#### *3.18. Energy Intake*

There were no significant differences in baseline energy intake (Table 1) of mRMR (Md = 2195.0, *n* = 21) and eRMR (Md = 2129.0, *n* = 19), U = 184, z = −0.420, *p* = 0.68, r = 0.07. There was no significant interaction between the intervention and time on energy intake (Table 5), F(1, 28) = 0.003, *p* = 0.956, partial η <sup>2</sup> = 0.000. The main effect of group showed no significant difference in energy intake between the intervention groups, F(1, 28) = 1.225, *p* = 0.279, partial η <sup>2</sup> = 0.042. The main effect of time showed a substantial statistically significant difference in energy intake at the different time points, F(1, 28) = 14.934, *p* < 0.0005, partial η <sup>2</sup> = 0.348. Post hoc analysis revealed that energy intake was significantly lower at week 12 compared to baseline (−479 kcal/day, *p* = 0.001).

#### *3.19. Measured Resting Metabolic Rate*

There were no significant differences in baseline measured RMR (Table 1) between mRMR (Md = 1604.00, *n* = 29) and eRMR participants (Md = 1691.00, *n* = 23), U = 347, z = 0.249, *p* = 0.804, r = 0.04. There was no significant interaction between the intervention groups and time on measured RMR (Table 5), F(2.421, 87.171) = 0.284, *p* = 0.794, partial η <sup>2</sup> = 0.008. The main effect of group showed that there was no significant difference for measured RMR between the intervention groups, F(1, 36) = 0.101, *p* = 0.752, partial η <sup>2</sup> = 0.003. The main effect of time showed no significant difference for measured RMR over time, F(2.421, 87.171) = 1.525, *p* = 0.220, partial η <sup>2</sup> = 0.041.

#### *3.20. Respiratory Exchange Ratio*

There were no significant differences in baseline measured RER (Table 1) between mRMR (Md = 0.77, *n* = 29) and eRMR participants (Md = 0.81, *n* = 23), U = 381, z = 0.876, *p* = 0.381, r = 0.12. There was no significant interaction between the intervention groups and time on RER (Table 5), F(2.339, 84.206) = 1.112, *p* = 0.340, partial η <sup>2</sup> = 0.030. The main effect of group showed that there was no significant difference in measured RER between the intervention groups, F(1, 36) = 0.105, *p* = 0.748, partial η <sup>2</sup> = 0.003. The main effect of time showed no significant difference in RER over time, F(2.339, 84.206) = 1.159, *p* = 0.324, partial η <sup>2</sup> = 0.031.

#### *3.21. Predicted Resting Metabolic Rate*

There were no significant differences in RMR predicted by Mifflin et al. (1990) at baseline (Table 1) between mRMR group (1560.28 ± 221.71) and eRMR groups (1639.25 ± 272.21; t(51) = −1.164, *p* = 0.250, mean difference = −78.97 (95% CI, −215.13 to 57.18). There was no significant interaction between the intervention and time on eRMR (Table 5), F(1.83, 67.60) = 0.215, *p* = 0.787, partial η <sup>2</sup> = 0.837. The main effect of group showed that there was no statistically significant difference in eRMR between the intervention groups, F(1, 37) = 0.841, *p* = 0.365, partial η <sup>2</sup> = 0.022. The main effect of time showed a significant difference in eRMR over time, F(1.83, 84) = 12.88, *p* < 0.0005, partial η <sup>2</sup> = 0.258. Post hoc analysis revealed that eRMR was significantly lower (both < *p* = 0.0005) at week 6 (1.8%), and week 12 (1.9%) compared to baseline. Post hoc analysis revealed no significant difference between eRMR at week 3 versus baseline (0.3%, *p*= 1.0). Post hoc analysis revealed that eRMR at week 6 (1.4%) and week 12 (1.6%) was significantly (both < *p* = 0.023) lower

than eRMR at week 3. Post hoc analysis revealed no significant difference between eRMR at week 6 versus week 12 (0.2%, *p* = 1.0).

#### **4. Discussion**

The aim of this study was to compare the efficacy of a dietary intervention (mRMR versus eRMR) on weight outcomes in Irish adults aged 50 years and over with overweight and obesity. The primary outcome of this study indicates that employing a reduced-calorie diet using IC to determine energy needs when improving weight outcomes in adults with overweight and obesity is equal to employing a reduced-calorie diet based on the Mifflin et al. [28] prediction equation. Following the study period, a significant (*p* < 0.05) reduction in body weight was observed in both mRMR (−4.2% of initial body weight) and eRMR (−3.2%) groups. However, there were no significant (*p* ≥ 0.05) differences between groups. Overall, 20.8% and 17.4% of mRMR and eRMR participants, respectively, experienced clinically meaningful weight reduction. One participant in the eRMR group experienced a 10–14.9% weight reduction, and one participant in the mRMR group experienced a more than 15% weight reduction. Rapid weight loss may be a sign of underlying health conditions or chronic disease. No health condition, disease or illness was identified prior to or during the intervention that may be attributed to rapid or unintentional weight loss. From the one-to-one consultations, it can be assumed that the observed weight loss may be attributed to successful adherence to diet and lifestyle modifications. While a secondary analysis of data assessing biological sex differences in weight variation within the mRMR and eRMR groups was not investigated in the present study, a previous study [46] with similar participants investigated gender differences in weight and BMI variation in response to a dietary intervention based on measured RMR using IC and equations. No statistically significant differences in body weight and BMI variation between the two IC and no IC groups were found between males and females (three-way interaction time by treatment by gender: *p* = 0.16 for BMI, *p* = 0.11 for weight), although a trend to a greater weight loss in females was observed in both groups. Secondary outcome measures revealed a significant reduction (*p* ≤ 0.05) in BMI, WC and muscle mass in both groups. Differences observed between groups were not significant (*p* ≥ 0.05). There were no significant (*p* ≥ 0.05) differences in percent body fat over time or between groups. Both groups experienced a significant (*p* ≤ 0.05) reduction in systolic and diastolic BP following the intervention period. Blood glucose and triglycerides were significantly (*p* ≤ 0.05) lower in both groups and there was no significant (*p* ≥ 0.05) difference observed between groups. There was no significant (*p* ≥ 0.05) difference for total cholesterol or TC:HDL over time or between groups. HDL concentration was significantly (*p* < 0.05) lower in both groups with no significant difference (*p* ≥ 0.05) between groups. No significant difference (*p* ≥ 0.05) was observed for LDL over the study period. However, there were significant (*p* < 0.05) differences in LDL between groups at baseline, and 47% of participants in the eRMR group displayed an upward trend in LDL over the study period (Figure 3).

In contrast, previous studies reported significant between-group differences when comparing similar dietary interventions (i.e., prediction equations versus metabolic based) in a comparable population [46,47]. Participants following a nutrition plan based on eRMR for a period of 90 days experienced a 2% weight reduction compared to −4.5% when following a diet based on mRMR [47]. The between-group differences may be explained by the methodical differences used to estimate RMR. Massarini et al. [46] employed the Harris and Benedict [48] prediction equation while McDoniel et al. [47] employed the American College of Chest Physicians (ACCP) prediction equation (25 × baseline body weight (kg) − 250 to 500 kcal/day) [5,49]. The application of prediction equations provides a source of variability as often they are utilised for a population which they were not originally developed for, thus resulting in reduced accuracy among specific populations [50,51]. Later work conducted by McDoniel et al. [52] in a similar population reported similar results to the present study. McDoniel et al. [52] conducted a 24 week randomised controlled trial, where usual care participants received a fixed low-calorie diet (i.e., 1200 kcal/day

for females and 1600 kcal/day for males, respectively) and participants in the metabolic diet (MD) group received an individualised nutrition plan based on mRMR. McDoniel and Hammond [52] reported a significant reduction in body weight at week 12, but similar to the current study observed no significant differences between the intervention groups. When comparing usual care practice to eRMR, participants following the fixedcalorie diet experienced a greater weight reduction (1.3%). Participants in the usual care group experienced a 4.5% reduction in bodyweight compared to the eRMR group (−3.2%) in the present study. It is reasonable to assume that the greater weight reduction observed by McDoniel and Hammond [52] in the usual care group may be attributed to a greater energy deficit compared to participants in the eRMR group. Usual care participants were prescribed approximately 300–500 kcal/day less than eRMR participants (Table 7) (females: 1500 ± 141 kcal/day; males: 2100 ± 236 kcal/day). Standardised hypocaloric balanced diets are designed to facilitate a 0.5–1.0 kg per week weight reduction by consuming approximately 500 kcal/day less than required for weight maintenance. This is based on the assumption that a negative energy balance of 7700 kcal is required for a 1 kg reduction in body weight. Therefore, an energy deficit of 3500 kcal/week should result in a 0.5 kg/week weight reduction. McDoniel et al. [53] prescribed similar energy intakes to that described in this study and observed comparable results. Participants in the self-monitoring and RMR technology (SMART) group received a nutrition plan based on mRMR and usual care participants were prescribed a standardised ad libitum diet (females:1200 kcal/day; males:1600 kcal/day). Participants in the SMART group experienced a 3.9% weight reduction, slightly lower than but similar to participants in the present study (−4.2%) employing comparable metabolic based diets (mRMR). Energy prescription was based on RMR measured by IC, which may explain the similarities. For instance, women in the mRMR and SMART group were prescribed 1584 ± 271 kcal/day and 1656 ± 334 kcal/day, respectively, while men in the mRMR and SMART group were prescribed 2180 ± 253 kcal/day and 2296 ± 565 kcal/day, respectively. The current study observed a weight gain equal to or less than 2% of initial body weight in 20.8% and 30.4% of participants in the mRMR and eRMR groups, respectively. Factors possibly contributing to an increase in body weight despite a reduced energy prescription include difficulty in adopting positive behaviour change to support dietary changes and thus influence weight.

Secondary outcomes of this study support previous research demonstrating that modest weight reduction lowers blood pressure, triglycerides and glucose [54]. A reduction in systolic (mRMR −2.8 ± 1.1 mmHg; eRMR: −7.0 ± 4.3 mmHg) and diastolic (mRMR: −3.3 ± 2.6; eRMR: 2.9 ± 0.0 mmHg) blood pressure, triglycerides and glucose was observed (Tables 2 and 4). These outcomes may be attributed to components of the dietary intervention which emphasise high fruit and vegetable consumption and intake of wholegrains, while reduced sodium and saturated fat intake, and limited intake of energy dense foods. A high intake of vegetables and fruit is associated with reduced blood pressure and a lower risk of CVD. Furthermore, dietary fibre intake and consumption of wholegrain products are linked to a lower risk of diabetes and reduced diastolic blood pressure, while lowering sodium intake reduces blood pressure [55]. Similar to Zinn et al. [56] a non-significant upward and downward trend in LDL was observed in the eRMR and mRMR groups, respectively, with 47% of participants in the eRMR group displaying an upward trend of LDL and 31.6% of participants in the mRMR group showing a downward trend in LDL (Figure 8). A systematic literature review evaluating the effect of energy restriction diets on weight loss outcomes in adults with overweight and obesity reported significant reductions in FFM or lean body mass in six of the included studies (*n* = 216) [57]. Muscle mass was significantly reduced at week 3 (0.8 kg) and week 12 (2.1 kg) compared to baseline (Table 2). Loss of FFM is unfavourable for numerous reasons including the impact on metabolic health, functional capacity, i.e., the ability to carry out activities of daily living and the increased risk of injury associated with reduced functional capacity. Greater FFM is linked to a higher metabolic rate, which is advantageous for weight reduction. In an effort to offset the potential loss of FFM, the present study encouraged adherence

to current national physical activity guidelines. National physical activity guidelines for older adults recommend at least 30 min a day of moderate-intensity activity on five days a week, or 150 min per week. The addition of moderate-intensity aerobic exercise, primarily walking, to intentional weight loss has been shown to attenuate the loss of muscle mass in older adults with overweight and obesity [58]. Aerobic activity, muscle-strengthening and balance activities form part of the recommendations for adults (Get Ireland Active, HSE). Despite the effort made by participants in this study to attenuate the effects of lean mass loss, a significant decrease was observed.

There was no significant difference in RMR measured by IC at baseline or across the intervention period for both groups (Tables 1 and 5). This observation supports previous studies that suggest resting energy expenditure remains relatively stable following modest energy deficit diet. Severe energy restriction is associated with greater loss in metabolically active tissue, and thus results in metabolic adaptation [59]. A recent systematic review demonstrated that resistance exercise was effective for increasing RMR. However, the same was not apparent for aerobic exercise [60]. This is an important finding given that the addition of physical activity to weight management programmes is an accepted practice to encourage energy expenditure. It is unclear whether the addition of resistance exercise specifically to weight reduction programmes may attenuate metabolic adaptation by increasing RMR. Future research is required to determine the extent to which resistance exercise affects metabolic adaptation of RMR related to energy restriction.

RMR estimated using the Mifflin et al. [28] prediction equation was lower than actual RMR for both groups (Table 5). eRMR was significantly lower at weeks 6 and 12 compared to baseline for participants in both the mRMR and eRMR groups. If eRMR was lower than actual mRMR, then participants following a diet based on estimated energy needs would receive a dietary plan underestimating calorie requirement and, therefore, greater weight loss would be anticipated. When separated out, male and female analysis of energy intake estimated using 3-day food diaries indicate that both male and female eRMR participants were under their prescribed intake at week 12, leading to further deficit than required (Table 7). Given that similar weight loss was evident between the eRMR and mRMR groups, this would suggest that the same weight loss may occur with a higher-calorie plan.

Furthermore, results from this study suggest energy intake closely matched to mRMR results in higher level of dietary adherence in male participants. Estimated male energy intake (2052 ± 597 kcal) from 3-day food diaries was very similar to energy intake prescribed using mRMR which is advantageous in weight reduction strategies. Strong adherence level is associated with successful outcomes in weight management [61]. A recent study investigating sociocultural gender factors which influence food behaviours, such as dietary preferences and adherence, reported that men were more adherent to a healthy low-carbohydrate (HLC) than women (*p* = 0.02) vs. healthy low-fat (HLF) diet [62]. Another possible reason for this may be the addition of regular one-to-one support provided by the researcher, where goal setting and self-monitoring of food intake were encouraged using motivational interviewing techniques and behavioural change skills. This may not be the case for women as estimated energy intake for females (1736 ± 473 kcal) was higher than prescribed and indicates that additional support may be warranted to aid adherence to weight management programmes for females. Assessment of energy intake is often unreliable, particularly in individuals classified as overweight or affected by obesity [14]. Therefore, a greater frequency of dietary self-monitoring, which is associated with greater weight loss success, may benefit females [63].

#### *4.1. Strengths of Study*

This research was unique in that it was the first study to compare RMR estimated by the Mifflin et al. (1990) prediction equation using actual body weight to inform dietary prescription directly to dietary prescription based on measured RMR value in this specific population group, namely Irish adults aged 50 years and over with a BMI <sup>≥</sup> 25 kg/m<sup>2</sup> and of Caucasian ethnicity. Thus, the results of this study may be extrapolated to Irish adults

aged 50 years or over with a BMI greater than 25 kg/m<sup>2</sup> . A major strength of this research was the level of adherence to the intervention, as a 93% retention rate was observed. For power based on weight reduction calculations and allowing for a 20% drop out, 46 people were required in total (approximately 23 in each intervention group). Fifty-two participants completed this study, thus allowing for statistical significance. Extensive support was provided by the researcher to all participants during this study, with regular one-to-one support, individualised nutrition coaching and accessible to participants should they have any questions or concerns. The researcher was certified in motivational interviewing and behaviour change skills, which, alongside a non-judgemental patient-centred approach, enhanced the consultation process and gave the participants an opportunity to engage in the conversation about health concerns relating to their weight. McGowan [64] highlighted the importance of strong communication skills, avoiding stigmatisation and the appropriate use of person-first language as imperative to successfully engaging patients. This level of engagement allowed for individual adjustments to be made where necessary and highlights that, irrespective of how the calorie deficit is achieved, it is the individualised and tailored approach that is the most important factor for retention and thus achieving a successful outcome. Further strengths of this study include consistent data collection by the same researcher, which reduces potential measurement error.

#### *4.2. Limitations*

There are a few limitations to this study. A secondary analysis of data for biological sex differences in weight variation within the mRMR and eRMR groups, or other sex-related factors, such as genotype, hormones, metabolic syndrome, or psychosocial factors that may affect either adherence to dietary intervention or weight reduction response were not investigated. Aronica et al. [62] highlighted the need for such analysis while acknowledging that a limited amount of weight reduction studies demonstrated sufficient power to compare the effects of energy restriction diets on weight outcomes in women vs. men. The present study duration was 12 weeks, thus it is unknown whether participants in the mRMR or eRMR groups maintained weight reduction over a longer period. While qualitative measures were collected at baseline to estimate the energy expenditure associated with physical activity and to inform the subsequent dietary intervention accurately, measuring energy expenditure associated with physical activity throughout this study using measurement devices such as the gold-standard doubly labelled water method or wearable monitors such as accelerometers and movement sensors was beyond the scope of this study. Some participants may have become more physically activity as this study progressed and so the contributory mechanism of physical activity energy expenditure to weight outcome remains speculative. Finally, all participants in this study were of a specific age range (≥50 years), BMI class (25 kg/m<sup>2</sup> ) and ethnic group (Caucasian) and thus caution should be used when extrapolating these results to other population groups.

#### *4.3. Future Direction*

Based on these data, the use of RMR technology demonstrates promise for effective weight reduction outcomes. Future research is needed to better understand the efficacy of RER and substrate utilisation information in tailoring dietary prescription. To address the gap in the literature as identified by Aronica et al. [62] biological sex differences such as body composition and metabolism should be investigated among research participants to compare the effects of diets with energy prescription based on IC or prediction equations on weight outcomes. Furthermore, sociocultural gender factors which influence food behaviours such as dietary preferences and adherence should be explored. The high retention rate (93%) demonstrated in this study would suggest that participants are more likely to adhere to a modest calorie-deficit nutrition programme with regular support. The effects over longer time frames are less clear and future research is required to investigate whether compliance to a modest calorie deficit is more suited to older adult population long term. Future research should accurately measure physical activity energy expenditure to determine its contribution to weight outcomes. Additional research is needed to determine the extent to which resistance exercise affects metabolic adaptation of RMR related to energy restriction.

#### **5. Conclusions**

In conclusion, the results of this study suggest that a reduced-energy diet based on mRMR or eRMR facilitates weight reduction in adults aged ≥ 50 years over the short term (12 weeks) and favours a reduction in blood pressure, triglycerides and glucose, thus reducing CVD risk factors. Overall, 20.8% mRMR and 17.4% of eRMR participants experienced clinically meaningful (i.e., ≥5% of initial weight) weight reduction. Moreover, dietary approaches that entail modest calorie deficit combined with individual counselling using MI and behaviour change skills that support and encourage small behaviour changes may be effective in short-term (up to 12 weeks) adult (aged ≥ 50 years) weight management.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/10 .3390/nu13041229/s1. Supplementary Figure S1 Informed consent was obtained from all subjects involved in the study

**Author Contributions:** Conceptualisation, C.C. and L.R.; methodology, C.C., L.R. and M.M. software, C.C.; validation, C.C. and L.R.; formal analysis, C.C.; investigation, C.C.; resources, L.R. and C.C.; data curation, C.C.; writing—original draft preparation, C.C.; writing—review and editing, C.C., E.D., M.M. and L.R.; visualisation, C.C.; supervision, L.R.; project administration, C.C. and L.R.; funding acquisition, L.R. All authors have read and agreed to the published version of the manuscript.

**Funding:** C.C. was the recipient of a scholarship awarded by the Irish Smart Ageing Exchange (ISAX) and the Research and Innovation Strategic Endowment (RISE) scholarship scheme (GMIT).

**Institutional Review Board Statement:** The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Research Ethics Committee of Galway Mayo Institute of Technology (GMIT), Ireland (protocol code RSC\_AC230119 and date of approval 23 January 2019). Informed consent was obtained from all subjects involved in the study.

**Informed Consent Statement:** All participants provided written informed consent prior to their inclusion in this study.

**Data Availability Statement:** The study was conducted in accordance with the Data Protection ACT, 2018 and approved by the Institute's Data Protection Officer. Researchers seeking the analysis dataset for this work should submit requests to the corresponding author.

**Acknowledgments:** The authors are grateful to all the participants for their time in contributing to this research. We acknowledge and thank the Department of Natural Sciences, School of Science and Computing at GMIT for the use of laboratory equipment and facilities. The authors would like to acknowledge and thank Nóra Ní Fhlannagáin RD and Emma Finnegan for their contribution to the dietary intervention.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

