Hello! as to why some women gain weight when they go on hormonal birth control?
I’m a big fitness person and believe that calories in v calories out is what makes you put on weight. If someone is still working out and their diet hasn’t changed but they began hormonal birth control, why are they putting on weight? How does this happen?
I’m genuinely curious and would love some insight. Thank you.
In: Biology
It’s still calories in vs. calories out, but what you’re not seeing is that the “Calories Out” side of the equation is mostly driven by your metabolism, not your exercise routine (with the obvious caveat for someone who is exercising multiple hours every day).
All animals burn a certain number of calories every day just to stay alive. For warm-blooded big-brained animals, that number is quite high. For an average-sized woman, probably 1400-1800 calories per day are consumed just to maintain body temperature, brain activity and basic functions. These activity levels are largely controlled by your hormones.
When you go onto hormonal BC, this disrupts the natural ebb and flow of hormones that accompanies the menstrual cycle. This, in turn, impacts the baseline metabolism of the woman in question, so her body is no longer burning as many calories just to keep her alive. So if she doesn’t adjust either her activity level or her diet, she’ll still have the same “Calories In” value, but her “Calories Out” value will drop.
It’s the same reason that it’s more difficult for people with certain medical conditions (hypothyroidism, for example) to lose weight, especially if we’re not medicated properly. Our bodies don’t burn enough calories, so it’s harder for us to reach a calorie deficit. We’re not more efficient with our calories or anything like that – we just don’t burn enough of them. It’s like trying to run a car with an undersized engine.
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