We had a surprise kid after my wife did shift work for around 5 months. She was only able to eat once or twice a day because she was so busy. She also had PCOS.
So I think it’s more about consistency than a one-off weeklong fast.
Look up ex-vegan videos. Plenty of instances where people start eating A LOT more meat and then getting their cycles back.
Saturated animal fat is probably the most important food for fertility. It signals an abundance of nutrient-rich food is available. Arguably, grains and plants are what we ate when we couldn’t land a big kill. They are sometimes referred to as starvation foods.
She needs to fast regularly, I’ve also heard and seen people get pregnant after starting keto so maybe she just needs time and be consistent with it! I too have PCOS and am on a similar journey though not planning to get pregnant just yet.
Fasting can help with fertility problems but it will take time. She would need to commit to doing it regularly for months. She needs to definitely cut out junk foods, alcohol, smoking, etc (though if you guys are already TTC hopefully she’s already done it.)
Personally, I’d also limit dairy products.
The other poster is right. An issue like this isn’t a one and done.Is she having any menstrual cycles?