Background
Serum thyroid-stimulating hormone (TSH) levels change during body weight reduction. However, the changes that occur during short-term body weight control interventions remain controversial. Thus, this study aimed to evaluate the changes in TSH levels according to body fat reduction.
Methods
We performed a 3-month intervention study involving partial meal replacement. Forty-nine participants completed the study. Correlations between changes in TSH levels and other body composition parameters were determined. The subjects were divided into two groups according to their body fat reduction (>1 kg, n=20; <1 kg, n=29). The changes in metabolic parameters, including TSH levels, were compared. For significant values, a multivariate analysis was performed after adjustment to evaluate the relationship between TSH changes and body fat reduction.
Results
The 3-month intervention caused favorable changes in body proportions and metabolic parameters. TSH levels changed significantly only after changes in total body fat, showing a partial correlation. Changes in TSH levels were significantly different between groups (P=0.014). Moreover, the change in TSH levels was significantly different after adjustment (P=0.012).
Conclusion
A body fat reduction, especially >1 kg, can reduce serum TSH concentrations in subjects with metabolic syndrome after short-term body weight intervention.

Citations

• The impact of weight loss interventions on thyroid function: a systematic review and meta-analysis
  Sandeep Samethadka Nayak, Seyyed Mohammad Hashemi, Masum Patel, Nimra Shafi, Pubali Biswas, Sepide Javankiani, Padmavathi Jaladi, Sanjana B. Patil, Rahiq Rashid, Ehsan Amini-Salehi, Daniyal Ameen, Khushbu Viresh Janani, Anil Kumar Jonnalagadda, Kwame Boat
  Annals of Medicine & Surgery.2025; 87(7): 4484.     CrossRef