You may have heard the rumors about cortisol. It’s the stress hormone and, because of that, it often gets a bad rap. The reality, however, is that cortisol is simply trying to help.
Produced by the adrenal glands, cortisol is the body’s natural anti-inflammatory, making it critical to your survival and protecting you from the effects of stress. When you’re stressed, cortisol rises because it senses that the body is in crisis.
Unfortunately, our bodies haven’t evolved much over the millennia, so cortisol has no idea that you’re planning your wedding, perfecting a presentation, or arguing with your kids rather than running from a predator or trying to survive a famine.
When your body thinks it’s in a state of emergency, it’s cortisol’s job to make sure you don’t starve to death in the process. To do that, cortisol prompts the body to divert resources away from functions like metabolism and weight loss.
The thyroid enters stage left
This is the point in the story where we introduce another organ into the mix: the thyroid. Your thyroid makes a storage form of thyroid hormone called T4. Your body, on the other hand, can only use the thyroid hormone T3, so it needs to convert T4 into the free, unbound form of T3.
This conversion happens mainly in the liver and kidneys, and once it occurs, free T3 goes to work fitting into different receptors that cause positive metabolic reactions.
Unfortunately, in many people, this thyroid symphony is out of tune. Sometimes, the thyroid isn’t making enough T4, or the conversion from T4 to T3 simply isn’t happening. There are a number of factors as to why things don’t work correctly, but some of the most common ones include a lack of protein or iodine, an overworked liver, a nutrient deficiency, gut dysbiosis, or chronic infections like Lyme Disease or Epstein-Barr.
One of these things is not like the other
Stress is also a huge contributor as to why this thyroid cascade isn’t performing optimally. In the stress scenario, our friend cortisol makes its heroic appearance. Remember that cortisol is one of the hormones responsible for making sure you don’t die during crisis, so it begins encouraging the body to turn T4 into something called reverse T3.
Reverse T3 fits into the same receptors as free T3, but it doesn’t do the same job. Free T3 drives metabolism, helps you feel great, and assists in dropping extra pounds. Reverse T3 does the opposite: it tells the body to slow metabolism and hold onto fat. After all, you’ll need those fat reserves for energy because your body knows you can’t spend time eating and digesting when you’re in the throes of an emergency.
The problem is that perpetual stress ensures that reverse T3 keeps getting made while free T3 gets shunted. This relationship between cortisol and your thyroid hormones is one of the main reasons why stress can literally make you fat and miserable.
Testing your thyroid
Here’s where the plot thickens: even if you have “normal” thyroid levels based on your blood work, you could still be at risk because conventional blood work rarely tells the true thyroid tale.
Most doctors run a thyroid test that only checks the level of thyroid-stimulating hormone (TSH). This is misleading because TSH levels can look totally in range while other markers that usually don’t get tested (like free and reverse T3) can be problematic.
How does that make any sense? For one, your brain is satisfied with the level of thyroid hormones before the rest of the body, so it sends a message that there’s adequate stores of TSH, even when there’s not. Unfortunately, most traditional doctors only dig deeper into thyroid panels when TSH is off, so you’re usually not getting the full thyroid panel unless you push for it.
If you suspect an under-active thyroid, ask your doctor to run a full panel that includes TSH, free and total T4, free and reverse T3, and the common thyroid antibodies peroxidase and thyroglobulin. These antibodies can help you to identify if you’re at risk for an autoimmune thyroid condition like Hashimoto’s or Graves’ disease.
Once you get your blood work back, you can look at the ratio of reverse T3 to free T3 to see how your body is prioritizing the T4-to-T3 conversion in response to stress.
Ideally, you want your free T3 to reverse T3 ratio to be higher than two. If it’s not, you should explore ways to reduce your environmental stressors, including deep breathing, vagus nerve stimulation, meditation, yoga, and spending time in nature.
Working with a functional medicine doctor or nutritionist who can help you tailor your diet to balance or eliminate any internal stressors, identify hidden food allergies, or heal your gut can also go a long way in helping you shed weight while feeling calm, cool, and collected.