At some point or another many chronic dieters realize that their caloric restriction and excessive exercise is causing them problems. They may start to notice that they bloat up after meals, are tired all of the time, and are no longer interested in dating. To go along with these symptoms, they may discover a wacky hormone profile, with thyroid and sex hormones all over the place.
If you are one of those unlucky enough to experience these symptoms you might not see or accept them as a sign that you should probably stop dieting. In fact, if you are like me, you might have assumed that if you could just replace these hormones then the symptoms will disappear, and you could just go on dieting and exercising as usual.
“I just need to take some thyroid hormones to increase your body temp…”
“I just need hormone replacement to get my mojo back…”
And the list of prescriptions are endless.
But There is a Problem
If these hormones are low due to your extreme diet and exercise, then simply replacing these hormones is unlikely to fix your symptoms.
Why’s That?
The endocrine system is very complex. In fact, for almost every hormone there are often several other hormones that interact to produce an effect in the body. The biggest one of these hormones and the one most relevant to chronic dieters is leptin.
Leptin is called the master hormone because not only does leptin regulate the production of other hormones, but there is also much evidence that it also controls of how those other hormones are used and the signal that they produce.
You can think of the amount of leptin as a switch: If you are at a healthy body weight and thus have higher amounts of leptin, the switch is turned to “relaxed” mode. In relaxed mode, your brain and body care about long-term goals such as reproduction, friends, and relationships. Conversely, if you have been dieting for a while and you are far below your body weight set-point, then your leptin will be low, and thus the switch will be turned to “survival” mode. In survival mode, your body is not concerned with anything that doesn’t work towards your short-term survival.
The way your body sees it, there’s no point in having kids or visiting with family if you starve to death in the next few weeks,
I use this switch analogy to keep things simple, but in our bodies, this switch functions more like a dial because you are hardly ever in complete survival or relaxed mode, but rather some combination of the two. Just know that at varying amounts of leptin your body is predominantly concerned about one or the other.
Here’s an example of how this might look:
Joey, a male in his mid-thirties is dieting for summer. He gets to single digit bodyfat before he notices that he’s no longer interested in intimacy with his wife. He goes to his doctor to see what his options are. Unfortunately, while most docs are great, many are completely unaware that dieting can create anything but positive effects. Thus, rather than telling Joey that it is probably his body’s reaction to dieting, he prescribes him testosterone replacement therapy.
Now if Joey’s testosterone was low for reasons other than dieting, then simply replacing his hormones would probably work fine; however, because Joey’s leptin remains low, his body thinks he is still starving, and is therefore not interested in reproduction. Keep in mind that many of the other effects of the testosterone such as body composition and strength will still take place, but the effects of testosterone that are related to reproduction often don’t.
If you have seen the thousands of articles or commercials on associating testosterone with libido then this might be surprising to you, but a loss of sex drive is a very common symptoms during weight loss even when taking replacement therapy. In fact, based on the results of a survey I took of around 100 respondents, the men who dieted while on testosterone replacement were actually more likely to experience a loss or decrease in sex drive than those who were not on TRT. It seems crazy, I know, but thousands of people you compete in bodybuilding every year often have the same experience.
What About My Thyroid?
After being diagnosed as hypothyroid several years into yo-yo dieting, I was actually relieved–all I had to do was take this medication and all would be good, right?… But it wasn’t so easy, almost none of my symptoms went away. This introduced me to the giant online community of people trying anything to treat their thyroid. Anything from avoiding the thyroid med with a spec of gluten, to taking T3 only in doses many times more than the body produces naturally. Unlike T4, T3 is the active form of thyroid hormone that can take effect without first having to make any conversions. The idea is that low body-fat and thus low leptin prevents the conversion of T4 to T3, which does appear to be true. The problem is that the thyroid hormone is only a signal to produce energy, and cannot produce energy without sufficient calories. In fact, taking more thyroid meds while you maintain your caloric restriction will only decrease your metabolism further.
Thyroid Hormones Need Calories to Produce an Effect
Your thyroid hormones while dieting are low for a reason– they are matching the level of energy that you have available to burn. If you then take more thyroid meds rather than providing more energy through calories, then your body will begin to burn the little bit of energy that remains. This is effective in the short term, that is why bodybuilders often take thyroid meds while preparing for a competition. However, once you burn through your stored energy you are left with an excess demand for energy from the thyroid meds paired with a shortage of calories to utilize. This results in an even more drastic “starvation” response because there is now an even larger gap between your body’s perceived energy requirements and the energy that is available.
I write about this soon but this hints at the fact that rather than having a certain number of calories for your metabolism as a whole, your body allocates a certain number of calories to each group of functions. For example, taking thyroid meds while dieting, might signal to your body to allocate more calories to body temp and resting metabolic rate, but it take more calories away from digestion and reproduction. If this turns out to be true, then certain hormone profiles and diets prioritize some functions over others.
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