# Low-Carbohydrate (Ketogenic) Diet in Children with Obesity: Part 2—Hormonal Effects of the Ketogenic Diet

## TL;DR

A short-term ketogenic diet in children with obesity improves hormonal balance, supports weight loss, and restores menstrual cycles in girls with PCOS.

## Contribution

The study demonstrates that a well-formulated ketogenic diet improves insulin sensitivity and hormonal disturbances in children with obesity and PCOS.

## Key findings

- The ketogenic diet promotes weight loss and improves insulin sensitivity in children with obesity.
- Girls with PCOS experience restored menstrual cycles and reduced testosterone levels on the ketogenic diet.
- Thyroid hormone levels may change in children with Hashimoto’s thyroiditis, requiring monitoring and adjustment of therapy.

## Abstract

What are the main findings?
•A relatively short-term “Well-formulated ketogenic diet” in children with obesity is associated with hormonal changes that promote weight loss and improve insulin sensitivity.•The ketogenic diet leads to improvement of hormonal disturbances and restoration of the natural menstrual cycle in girls with PCOS.•The ketogenic diet does not adversely affect thyroid function in children without pre-existing thyroid disease; however, in patients with autoimmune Hashimoto’s thyroiditis, changes in thyroid hormone levels may occur, requiring adjustment of replacement therapy.

A relatively short-term “Well-formulated ketogenic diet” in children with obesity is associated with hormonal changes that promote weight loss and improve insulin sensitivity.

The ketogenic diet leads to improvement of hormonal disturbances and restoration of the natural menstrual cycle in girls with PCOS.

The ketogenic diet does not adversely affect thyroid function in children without pre-existing thyroid disease; however, in patients with autoimmune Hashimoto’s thyroiditis, changes in thyroid hormone levels may occur, requiring adjustment of replacement therapy.

What are the implications of the main findings?
•The ketogenic diet may be offered as an effective dietary intervention for motivated children with obesity and accompanying metabolic disorders.•The ketogenic diet may be included as part of a comprehensive therapeutic approach in the treatment of girls with PCOS.•During ketogenic nutrition, monitoring of TSH and thyroid hormone levels is recommended, particularly in patients with known pre-existing thyroid disease.

The ketogenic diet may be offered as an effective dietary intervention for motivated children with obesity and accompanying metabolic disorders.

The ketogenic diet may be included as part of a comprehensive therapeutic approach in the treatment of girls with PCOS.

During ketogenic nutrition, monitoring of TSH and thyroid hormone levels is recommended, particularly in patients with known pre-existing thyroid disease.

Background: For decades, the ketogenic diet has been successfully used for the treatment of obesity, metabolic syndrome, and type 2 diabetes. The mechanisms through which it affects metabolism are not fully understood, but the hormonal changes that occur during ketogenic nutrition are likely to play an important role. Objectives: To investigate the effect of the ketogenic diet on various hormones associated with obesity and the accompanying metabolic disorders in childhood. Methods: One hundred children aged 8–18 years with obesity were enrolled. After baseline anthropometric, biochemical, and hormonal testing, they followed a 4-month “well-formulated ketogenic diet.” Fifty-eight of them successfully completed the study with follow-up assessments. Among them, 8 girls had polycystic ovary syndrome (PCOS) and 7 children had Hashimoto’s autoimmune thyroiditis. Results: At the end of the 4-month period, there was a significant decrease in basal insulinemia (p < 0.0001) and in mean morning cortisol levels (p = 0.04), as well as an increase in adiponectin levels (p = 0.04). All girls with PCOS experienced spontaneous menstrual cycles, accompanied by a reduction in testosterone levels. TSH levels showed no change for the whole group (p = 0.13), but there was a significant decrease in T3 (p < 0.0001) and a mild increase in T4 (p = 0.05). Among patients with Hashimoto’s thyroiditis, TSH levels were significantly higher at the end of the study. Conclusions: A short-term, well-formulated ketogenic diet in children with obesity is associated with hormonal changes that support weight loss and improve insulin sensitivity. The diet shows particularly beneficial effects in girls with PCOS and may be considered as part of a comprehensive therapeutic approach in these patients. Monitoring thyroid function during ketogenic nutrition is advisable in patients with hypothyroidism and thyroid disorders.