As hyperthyroidism develops, some people actually enjoy the ability to eat anything they want without weight gain or even with weight loss. All the more reason to become your own best advocate, and push for diagnosis and treatment as early as possible. It can be even more, because the more weight you gain, the more efficient your body becomes at fat storage and the less active you typically become. Go undiagnosed for a year, and that's 36 pounds. If this resulted in a metabolism that was 350 calories a day less efficient, you could gain a pound or more every 10 days, or 3 pounds a month. So it's a triple whammy to your metabolism: you're eating more food, burning off even less of it because of a lowered basal resting metabolism, and doing less physical activity. Finally, as you become more tired, you may eat more to unconsciously try to generate energy. So you have another factor that can further reduce metabolism.

Untortunately, many people perience fatigue, low energy, and muscle pain, which makes them less likely to exercise. Even slight decreases in metabolism mean fewer calories burned every day, so even if you ate the same amount and kept up your same level of activity over time, you would see weight gain due to the slight reduction in metabolism. During this period, a variety of symptoms can appear, even before TSH elevates enough to officially qualify for a conventional diagnosis of hypothyroidism. For many people who become hypothyroid, it can be months or even years from the time their thyroid condition develops to when it is diagnosed and treated. I've focused primarily on hypothyroidism because the end result for almost all thyroid conditions is a surgically removed, radioactively ablated, or otherwise underactive or nonfunctioning thyroid - or hypothyroidism. Even if your thyroid treatment is optimized, as described before, as a thyroid patient you may still face a variety of challenges that make it more difficult to lose weight than it is for the typical person.