The Effects of Dietary Restriction in Obese Children
One hundred and twenty children were included in the study. The children had a mean age of 9.8 ± 1.6 years, a mean BMI of 28.1 ± 3.6 kg/m, a mean WHR of 0.96 ± 0.05, and a mean percent body fat of 41.01 ± 3.46. Their basal dietary consumption was as follows: kilocalories 2161 ± 606, lipids 31.6 ± 6.3 % and carbohydrates 54.1 ± 7.4 %. Initially the children were randomized into two groups. The data from both of the groups had a normal distribution and were similar compared with a t-test for independent variables.
The 2 months follow-up was completed by 53 (88.3 %) subjects on the L-CHO diet and 45 (75 %) with on the L-F diet. The children decreased their total caloric intake by a mean of 2436 kJ/day (582 kcal) after 8 weeks (p < 0.00003). The group on the L-CHO diet decreased 2554 kJ/day (616 kcal), t = 6.14, p < 0.0000001. The group on the L-F diet decreased 2457 kJ/day (587 kcal), t = 7.50, p < 0.0000001 a value within the range of expected dietary compliance.
After 2 months on the L-CHO diet, the BMI, leptin and FGF21 levels decreased. An increase in total cholesterol was observed as a result of an increase in high density lipoprotein cholesterol (HDL) levels. No change was found for HOMA-IR. In regards to eating behavior, food responsiveness, enjoyment of food and emotional overeating decreased significantly, and satiety responsiveness increased marginally (Table 1).
After 2 months on the L-F diet, the BMI, leptin levels, LDL-cholesterol and FGF21 levels decreased and HDL-cholesterol increased. Regarding eating behavior, food responsiveness and enjoyment of food decreased significantly and satiety responsiveness increased marginally (Table 2).
Table 3 compares the effect of both diets. The total and LDL-cholesterol levels significantly decreased with the L-F diet. A similar feeding behavior was observed in both of the groups.
Using the multiple regression procedure, we found that before the diet, FGF21 was positively associated with total cholesterol, triglycerides and BMI. After the L-CHO and L-F diets FGF21 remained associated only with triglyceride levels (Table 4).
Considering this association we examined the possible relationship of FGF21 with pubertal development. ANOVA for adrenarche stages in both sexes did not show an association with FGF21 (f = 0.005, p = 0.94). With univariate regression analysis for young boys, testicular volume was not associated with FGF21 (p = 0.22).
For the basal study, the only factor associated with leptin was BMI. After dietary treatment with the L-CHO and L-F diets, the association with BMI remained significant (Table 4).
Before the treatment satiety was negatively associated with screen time and insulin levels. After the treatment no factor was associated (Table 4).
In the multiple regression analysis for hormones and satiety, gender and age were not included in the model. In an additional analysis we divided both of the groups by ages 6 to 10 (n = 76), and >10 to 12 years (n = 22). In the 6 to 10 years of age group, the factors associated with leptin, FGF21 and satiety were the same as in the total group (Table 4); however in the >10 to 12 years group, leptin was associated with BMI before intervention, and after either diet. No associations were found with FGF21 or satiety. This finding indicates that in our group early pubertal activation is not adequately represented to show its influence on satiety or hormone changes.
Results
One hundred and twenty children were included in the study. The children had a mean age of 9.8 ± 1.6 years, a mean BMI of 28.1 ± 3.6 kg/m, a mean WHR of 0.96 ± 0.05, and a mean percent body fat of 41.01 ± 3.46. Their basal dietary consumption was as follows: kilocalories 2161 ± 606, lipids 31.6 ± 6.3 % and carbohydrates 54.1 ± 7.4 %. Initially the children were randomized into two groups. The data from both of the groups had a normal distribution and were similar compared with a t-test for independent variables.
The 2 months follow-up was completed by 53 (88.3 %) subjects on the L-CHO diet and 45 (75 %) with on the L-F diet. The children decreased their total caloric intake by a mean of 2436 kJ/day (582 kcal) after 8 weeks (p < 0.00003). The group on the L-CHO diet decreased 2554 kJ/day (616 kcal), t = 6.14, p < 0.0000001. The group on the L-F diet decreased 2457 kJ/day (587 kcal), t = 7.50, p < 0.0000001 a value within the range of expected dietary compliance.
Effect of Low-carbohydrate Diet
After 2 months on the L-CHO diet, the BMI, leptin and FGF21 levels decreased. An increase in total cholesterol was observed as a result of an increase in high density lipoprotein cholesterol (HDL) levels. No change was found for HOMA-IR. In regards to eating behavior, food responsiveness, enjoyment of food and emotional overeating decreased significantly, and satiety responsiveness increased marginally (Table 1).
Effect of Low-fat Diet
After 2 months on the L-F diet, the BMI, leptin levels, LDL-cholesterol and FGF21 levels decreased and HDL-cholesterol increased. Regarding eating behavior, food responsiveness and enjoyment of food decreased significantly and satiety responsiveness increased marginally (Table 2).
Comparison of Changes Between Both Dietary Interventions
Table 3 compares the effect of both diets. The total and LDL-cholesterol levels significantly decreased with the L-F diet. A similar feeding behavior was observed in both of the groups.
Factors Associated With the FGF21 Levels
Using the multiple regression procedure, we found that before the diet, FGF21 was positively associated with total cholesterol, triglycerides and BMI. After the L-CHO and L-F diets FGF21 remained associated only with triglyceride levels (Table 4).
Considering this association we examined the possible relationship of FGF21 with pubertal development. ANOVA for adrenarche stages in both sexes did not show an association with FGF21 (f = 0.005, p = 0.94). With univariate regression analysis for young boys, testicular volume was not associated with FGF21 (p = 0.22).
Factors Associated With Leptin
For the basal study, the only factor associated with leptin was BMI. After dietary treatment with the L-CHO and L-F diets, the association with BMI remained significant (Table 4).
Factors Associated With Satiety
Before the treatment satiety was negatively associated with screen time and insulin levels. After the treatment no factor was associated (Table 4).
Influence of Age on the Response to Macronutrient Restriction
In the multiple regression analysis for hormones and satiety, gender and age were not included in the model. In an additional analysis we divided both of the groups by ages 6 to 10 (n = 76), and >10 to 12 years (n = 22). In the 6 to 10 years of age group, the factors associated with leptin, FGF21 and satiety were the same as in the total group (Table 4); however in the >10 to 12 years group, leptin was associated with BMI before intervention, and after either diet. No associations were found with FGF21 or satiety. This finding indicates that in our group early pubertal activation is not adequately represented to show its influence on satiety or hormone changes.