I stumbled upon this article last week: Metabolic Assessment of Menstruating and Nonmenstruating Normal Weight Adolescents This is something that I have always been curious about — is amenorrhea associated with a low metabolic rate? I always assumed yes, at least a little bit. However, I didn’t really base this conclusion on any hard science. Let’s say that I used “Grey Science,” which goes something like this:
Your body requires a certain number of calories to function at full-capacity. When you chronically deprive your body of these calories, it has to adapt to the calorie deficit to survive. One of the ways that it does this is to cut out non-essential functions, like menstruation. However, in recovery, it’s possible to gain weight without really restoring your metabolism (believe me). If you’re still subsisting on a sub-optimal number of calories, then your body might still not feel like it can spare the extra calories that menstruation requires. You are only able to maintain that weight on those calories because there are still processes that are being cut out. This means that your metabolic rate is lower.
Again, this is my unscientific reason, that happens to make a lot of sense in my mind. Thankfully some researchers came along to actually research this…
From the article:
“The purpose of this study was to investigate a possible mechanism for amenorrhea in adolescents who were 90-130% expected body weight with a history of anorexia nervosa, bulimia nervosa, or eating disorder not otherwise specified. Using indirect calorimetry, we examined the metabolic differences between participants who were menstruating regularly compared with those who were amenorrheic. Our hypothesis was that participants with amenorrhea would have a lower REE than those with regular menses. We also proposed that both groups would have a lower REE than would be expected for age, weight, and height due to their dieting, calorie restriction, and eating disorder behaviors.”
And the conclusion:
“Using indirect calorimetry to assess REE, we showed that a hypometabolic state persists despite weight restoration. There were significant metabolic differences found in weight-restored participants was amenorrhea as compared to participants who had regular menses. Participants with amenorrhea consumed a lower fat diet, that a lower REE, and were at a lower mean body weight.”
So… overall, I was on the right track. However, the article leaves me with several questions:
- Why do recovered anorexics/bulimics have a lower REE than others their age without an ED history?
- What is necessary for resuming menses?
- I have been told by several doctors that often a stint on birth control is necessary to “jump-start” your period. How does that relate? And, how does that affect REE?
I think that the situation is a Catch-22. Weight-restored patients with amenorrhea have a lower REE, so their metabolic rate is reduced and therefore need fewer calories. However, they are still not getting their period, so do they need to be eating more? I understand that you need to eat more to raise your metabolic rate and get your period back (in theory), but as a weight-restored anorexic I will tell you that my ED is screaming, “See! You DON’T need that much food! Your metabolism is slower!” I think that it is a particularly difficult spot to be in since you can’t tell yourself “Well, you do need to gain…” I am waiting for a follow-up study that shows that increasing caloric intake fixes said metabolic and menstrual issues. Now THAT is a study I would be excited to read.
(Unrelated P.S. – This is the 100th Grey Thinking post!)