Hypothyroidism, or low thyroid output, does not significantly increase overweight and obesity rates. TSH levels in obese and overweight individuals are usually in the normal range. Subclinical hypothyroidism (as indicated by a TSH between 2.51 and 4.0 mU/L) was actually more common than clinical hypothyroidism (TSH above 4.0 mU/L) in overweight and obese subjects.
While thyroid hormones are tied with metabolic rate, free T3 increases with waist circumference… perhaps part of an adaptive response to weight gain.
Hypothyroidism causes a multitude of problems including fatigue and dry skin. Stress reduction techniques including proper sleep, proper diet, meditation and exercise may improve thyroid levels.