Among the most troubling side effects of this treatment is the feared weight gain. However, as far as we know, there is no clear evidence of this effect.
And yet, some claim that this relationship is real. Why is this so? Doesn't such a dramatic hormonal change have a noticeable effect? It certainly does, but not in the way that pop "folklore" claims.
What is the relationship between the birth control pill and weight gain?
The fact that the "side effects" of birth control pills claim that overweight is among them does not help. But the truth is that this statement is not correct in light of the scientific evidence we have right now. But let's start at the beginning. What is a birth control pill?
This treatment consists of administering a series of pills containing estrogen, progesterone and progestin, gross mode. The combination of these hormones varies according to the type of contraceptive pill and the period in which the substances are administered (which does not have to influence the period in which the pill is taken). These hormones are metabolically very important for the body.
They are related to the general metabolism, but especially to the sexual one. Under this premise, it is quite logical to think that the pill can influence weight gain, right? However, this contradicts the studies that have been done on the subject. Both progestin and combined estrogen-progestin pills have been shown not to have a direct relationship to weight gain, according to some interesting meta-analyses, which are the reviews that compile the results of many other studies.
According to these, based on clinical trials (conducted by studying treatment in humans), in the short term there is no weight gain in either case. In the long term there does not seem to be a relationship either, although the authors make it clear that more research is needed. In any case, the summary is as follows: There is no reason to think, as observed, that weight gain is part of the side effect of the birth control pill.
And yet...
However, many people will say with conviction that they gained weight. No one's saying they're lying, of course. What we are saying is that, if nothing changes, the use of the birth control pill does not have to induce weight gain (according to the evidence to date). Although it seems logical to think about the hormonal effect, the truth is that the pills only regulate the concentration of these substances in the blood. So it would be more logical to think that they will do just the opposite.
What about people who have put on weight? There can be many explanations. The most likely one is that they have changed some of their life habits. This usually happens because the treatment does have significant effects on the metabolism. On the other hand, in some cases temporary fluid retention could occur, something that would distort perception.
The Most Heard Myths About the Birth Control Pill
Weight is a rather unreliable and very fickle measurement. Maybe it's just the result of a bad perception. The last point is precisely linked to this: Maybe apophenia (the inherent human tendency to find patterns) is playing tricks on us. In any case, we cannot blame the pill for the fat gain on its own, at least in the short and medium term (although probably not in the long term either).
What does happen: the loss of muscle
If we continue to look for a hormonal relationship we may find this: the birth control pill causes less muscle gain. With this result, a research team was found that tried to elucidate some basic questions of muscle building. In particular, they observed that young women taking the contraceptive pill gained up to 40% less muscle than their male and female partners.
The team's explanation involves the hormone dehydroepiandrosterone, or DHEA. The body produces the hormone dehydroepiandrosterone naturally in the adrenal gland. In turn, dehydroepiandrosterone helps produce other hormones, including testosterone and estrogen. Dehydroepiandrosterone levels peak in early adulthood and then slowly fall as we age.
In addition, this hormone is involved in muscle production by being a precursor to testosterone. Women on contraceptive treatment showed significantly lower levels of testosterone, which results in less muscle generation. Could this be related to weight gain in the long run? It is a possibility.
As we have said on many occasions, the body is very complex and multifactorial. That means that we are subject to an infinite number of variables. Not everyone is affected equally by the same treatment. At the moment, we have some evidence that is clear, but who knows if we will soon have others that will disprove what we think we know so far?