Is there a link between these two?
According to the National Institutes of Health, the amount of hormones your thyroid releases affects your weight (NIH).
If too little of the hormone is released by your thyroid, you have a disorder called hypothyroidism, which can cause weight gain. However, if too much of the hormone is released by your thyroid, you have a disorder called hyperthyroidism, which, can cause weight loss.
Read more here