I just cut out of my diet soy, wheat, and most other grains and immediately had a two-day increase in my next LP. My LP has been consistently borderline short (10/11 days) for months.
I think it was mostly the soy. I had soy milk almost daily (six days/week) in smallish quantity, but for about 12 years straight. I have one dd who started going into puberty early--she drank soy milk as well. My oldest did not develop early--she on the other hand hates soy milk and never drinks it. Not exactly scientific but it impressed me.
I also have melasma--a skin pigmentation problem on my face associated with hormone imbalance (it's the same thing as the hormone-triggered "mask of pregnancy" but my youngest was 5yo when it started). It looks better right now but IDK if it's just because I'm getting less sun. I have my fingers crossed that it will not show up full force next summer.
This would all be related to too much estrogen throwing off the progesterone BTW. AKA estrogen dominance. I think this also slowed my temp rise and made my LP temps erratic. I agree with the PP about there being many factors that contribute to estrogen dominance. Some of them we do have choices about, thank goodness.
Tear, I have also read something about the low-fat dairy reducing fertility, though I didn't learn anything about how. However, I also thought (from other sources) that full-fat dairy was pro-fertility and we do have quite a bit of that. We'll see how that goes.