Just eat less and exercise more!
Tired of hearing that? I am, too. If you have trouble losing weight and keeping it off, then you’re in the right place. You know it’s more complicated than that simple statement. You’ve succeeded at many other things, but this just isn’t working. Maybe you can lose 10 or 20 pounds. Then the system seems to step on the brakes. You’re still doing the same behaviors that helped you lose that weight, but now the scale doesn’t budge. And you seem to be thinking about food even more than usual. Some foods are constantly calling your name.
This is not a lack of will power. Here’s the truth: Your body isn’t much different from people of the Stone Age. Fred Flintstone wouldn’t have had excess weight. Their challenge was getting enough food to survive rough times. So, when you aren’t eating enough food to maintain your current weight, primitive pathways kick in.The brain says, “Hey, if we can’t find more food, we’re going to die!” Changes in brain chemistry and hormones respond to keep you alive in the famine:
Interest in food increases.
The stomach requires more food to feel full.
These two changes last for at least a year after weight loss.
Your body’s metabolism is lowered to burn fewer calories at rest.
- The lowered metabolism makes you tired, and possibly depressed, so you become less active.
Your muscles become more efficient, so when you work out, fewer calories are burned for the same amount of work.
The decreased metabolism may last at least six years after weight loss.
While many weight loss specialists prescribe medications that can reduce appetite, few pay attention to the decreased metabolism part because they don’t understand what’s going on. I’ve followed the scientific literature about thyroid and weight for years.
And for the past 20 years, I’ve been treating what I call “famine response hypothyroidism.” Decreases in the level of the active thyroid hormone (T3) occur in about 90% of people who try to lose weight. Since the late 1970’s, providers have measured thyroid stimulating hormone (TSH), treated with T4, and assumed the T4 was converted to T3. We were all taught that T4 is converted to the active hormone liothyronine (T3), so why bother to measure it?
Almost no one measures the actual active hormone. Got that? If your TSH and T4 are fine, your provider will say “Your thyroid is fine; you must be eating more than you think.” And while controversial, they also don’t measure reverse T3 (rT3) which goes up in some patients when they’re suffering from insufficient food. rT3 may have a role in slowing metabolism.
And where is the T3 when you’re trying to lose weight? It’s often at the low end of normal with some low thyroid symptoms as shown below. But TSH is perfectly normal the whole time. (Note the gray area is the normal range for both hormones.)
So, patients have symptoms of low thyroid, stop losing weight, and their T3 is at or near the bottom of normal. Most providers don’t see this at all because they don’t measure T3.
When we get the thyroid right (no low or high symptoms – and T3 within normal range), using appetite suppressants if needed, then losing weight and keeping it off is possible.
Maybe you don't have a weight problem, but you're convinced your thyroid is low despite a normal TSH. Or, your thyroid is treated, but you still don't feel well.
Over the years, I’ve seen people who are treated with T4, have normal TSH values, but if we ask about symptoms and look at T3 (and rT3), we find that their T3 is less than midrange. Adding T3 makes them feel like themselves again: good mood, energy, etc.