Women - menstrual cycle, weight, and fitness matters

Hey ladies!

We get a lot of threads with titles like “TOM--gained a pound!” or “PMS and can’t stop eating!” This is my attempt to create a reference thread about those issues. Please add any info (especially good websites/resources/articles) that you may have about this subject.

Menstrual cycle basics

If you would like a much longer and well-illustrated explanation compared to the summary below, I urge you to watch this video. In general, though, your menstrual cycle has four phases:

1. Menstruation phase - This phase starts on the first day of your period and lasts from 3-7 days for most women. This is when your body sheds its uterine lining if you are not pregnant.
2. Follicular phase - This phase also starts on the first day of your period and lasts for around 13 days for a woman with a 28 day cycle. (Note: 28 days is an average but many women have different cycle lengths.) That means that the beginning of this phase runs concurrently with your period. This is when several of your eggs is maturing and getting ready for the next phase. Your body also starts to rebuild its uterine lining at this point.
3. Ovulation phase - This phase happens around the midpoint of your 28 day cycle. This is when one of the eggs that was maturing is released from its ovary and makes its way into your fallopian tube where it hangs out for a day. (Side note: If you get pregnant, your pregnancy is dated from the first day of your last menstrual period, not from the date of conception or ovulation.)
4. Luteal phase - This phase starts the day after ovulation. Your egg either meets and joins up with a sperm and fertilization occurs or it does not and simply disintegrates. If fertilization occurs, the fertilized egg makes its way to the uterus where it implants in the uterine lining. If fertilization does not occur, your progesterone levels eventually drop off, which triggers the shedding of your uterine lining. And thus another menstruation phase is born.

What does that have to do with losing weight?

Simply put, the hormonal changes (changing levels of estrogen and progesterone) that you go through during your menstrual cycle can cause you to retain water weight at both ovulation and leading up to your period. Water retention, or bloat, is commonly listed as a symptom of PMS, and it tends to peak on or around the onset of the menstrual phase. That means that a woman with a 28-day cycle could find herself retaining water every two weeks.

Now, water retention doesn’t occur for every woman and some women may find that they tend to retain water more at one point than at another but it is significant because a woman who has not previously tracked her weight may find it alarming or discouraging to see her weight loss stall (or reverse) every other week. For this reason, I am a big proponent of daily weigh-ins, as I believe that they help people understand the natural ebb and flow of their bodies’ weight cycles. If you know what to expect, you are less likely to be freaked out when it happens.

But why do I get PMS hunger? What should I do about it?

For the in-depth why, I suggest reading Lyle McDonald’s research review of this paper. It’s comprehensive but well-written and understandable. Here’s a quotation from the article:

The major increase in energy expenditure occurs also during the luteal phase (when hunger is increased) with increases of 2.5-11.5% having been reported.

So we are talking a 45 to 207 calorie expenditure increase for a woman whose normal daily energy expenditure is 1800 calories per day. On its surface it might not sound like a lot. But when you consider that you are trying to lose weight and are eating in a deficit of 250+ calories per day, you should be able to understand why that extra expenditure makes you feel so much more hungry. To me, at least, it makes sense that if you increase your deficit by 20-80% or more, you are going to feel more hungry.

As for what to do about the increased hunger, I suggest either decreasing your calorie deficit or eating at maintenance. Most women find that their hungriest period lasts only 2-3 days. Making the conscious choice to eat a bit more for 2-3 days a month can prevent an extreme hunger-fueled binge. If you are really bothered by this idea, you could even reduce your calorie goal the rest of the month to make up for eating more at this time. A reduction of 36 calories per day over 25 days would “make up for” an increase of 900 calories total over 3 days.

Before I close, here are a few articles/resources that I find helpful when it comes to the subject of being female and trying to lose or maintain weight and how being female may or may not affect your training.

• https://bodyrecomposition.com/research/menstrual-cycle-energy-balance
• https://breakingmuscle.com/period-periodization-harnessing-the-power-of-your-cycle/
• https://breakingmuscle.com/what-really-causes-irregular-menstrual-cycles-in-female-athletes/
• https://www.t-nation.com/training/the-hormone-cycle-and-female-lifters/

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