Obesity and thyroid hormone

The actions of thyroid hormone in the obese patient appear to be qualitatively similar to the effects in normal weight individuals, although there may be some small quantitative differences in the magnitude of the response. These effects include an increase in metabolic requirements, an increase in turnover of protein, fatty acids and calcium, and modification of enzymatic and hormonal systems.

The decision as to whether thyroid is useful in the treatment of an obese patient depends on the particular question. If the patient is clinically or chemically hypothyroid, there is little question that its use is necessary. For the euthyroid obese patient, however, there may also be a place for the judicious use of thyroid hormones. Such a situation might arise during profound caloric restriction when metabolic rate is known to decline. In this situation, the appropriate doses of thyroid hormone may obviate this physiologic adaption of caloric deprivation.