Longtime IF'er, sudden & persistent weight gain 2 years ago...HELP!

I'm 47F , 5'7", 160 lb and have been doing IF for 5+ years. For the first few years, I stayed on a 18:6 schedule, sometimes 20:4, and it worked beautifully to bring me down a few pounds and keep me at or below 150 lb. Since my early 20s, I've always weighed between 147-153 lb, except when I was pregnant (I have 4 kids). 2 years ago at age 45, I had a sudden weight gain of around 15 lb--almost overnight! Since then, I have tried everything I can think of and nothing has changed it more than a few pounds. Here are all of the things I have tried, on top of the normal 18:6 routine that is my base. Each of these things I've tried for several months straight to give myself enough time to see results (spoiler alert: none!). I am SO frustrated!I'm pretty active, averaging 10k-15k steps a day. I do cardio & weight lifting a few times a week plus lots of walking, gardening, etc.I first went back to 20:4, which in the past always worked if I saw my weight creeping up. This time...no change.Several months later, I went to more of a OMAD schedule, but I found that I was so ravenous that I probably ate more than if I was doing a 4-6 hour eating window....no change!About a year ago, I started adding a 36-42 hour fast 1x/ week, on top of the normal 18:6-20:4. No change even after 6+ months! Then I upped it to TWO 42-hour pasts per week, plus my usual 18:6-20:4. Still...no change! Not even a pound different on average after several months!About 6 months ago, I stopped the long fasts and started counting calories via MyFitness Pal, giving myself a 500 calorie deficit based on my age, weight, and activity level. I have been weighing everything to the last gram. On top of this, I've still been doing 20:4, which ends up being a light snack at 3 pm plus dinner at 6 pm...STILL NO CHANGE!I am still ~10 lbs over my normal baseline weight and feeling completely mystified. Most days my macros end up being 50% fat, 25% protein, 25% carbs just by function of how I eat, not because I'm aiming for anything in particular. I don't drink any calories or any artificially sweetened drinks. Just plain water. I'm not obese or overweight, but I am about 10 lbs over my normal healthy weight. I have some clothes that don't quite fit after this weight gain 2 years ago. I don't feel like I can decrease my calories any more and keep it sustainable. I'm definitely not quite satisfied when I hit my daily caloric max (around 1400-1500 most days). Help? ps--I'm a medical researcher by profession so I keep thinking, "Surely there must be some explanation for this! Surely I am not a strange outlier whose body defies the laws of thermodynamics!" via /r/intermittentfasting https://ift.tt/BWDVFOS https://ift.tt/xG2eifj