Your goal weight is getting closer, progress naturally slows.
So, I'm at a point in my IF/TRE 16:8 journey where I am starting to get fatigued and struggle a bit by the last few hours of a fast, where previously I could sail right through past the 16, to 18+ hours (never quite making it to 20, but not really feeling like it'd be that difficult if I wanted to).
I'm a little over 5 weeks in, and have lost a good amount of weight for my size and the time-frame (although now I've really hit a plateau). But now I'm getting light-headed, brain-foggy and generally feeling a bit depressed and clumsy at about the 15-16 hour mark. I'm also feeling *much* less motivated to exercise, even after multiple nights of good sleep. I'm pretty sure my nutrients are well balanced, as I'm quite rigorous with nutrition and supplementation. I'm a whole-foods, low-moderate wholefood carbs, moderate-to-high protein, plant-forward (but not exclusive) gal. I do think it's calories and timing, but I'm not quite sure what the matrix is yet.
I would love some advice from folks with similar experiences here as to whether the best course of action is to a) hold and continue, or b) eat at maintenance for a minute, or c) something else altogether that I haven't considered, that might help me feel less crappy near the end of a fast, more eager and energised to exercise, help break the plateau, and not risk me gaining any of my hard-won fat loss back. If such a thing is possible...!
Backstory / details: I'm a mid-40s cis-woman (in peri, for sure): I started 16:8 + tracked small-moderate calorie deficit + deliberate macros about 5 or so weeks ago (roughly 300-350cal deficit daily, very decent amount of protein for my size). Lost about 7lbs / 3.2kg in the first 4 weeks (much of it water weight, granted). This was a HUGE turnaround for me, given I couldn't shift a single ounce previously, no matter how hard I tried to restrict or exercise, in fact I just kept gaining weight.
At the same time as starting fasting, I also shifted away from doing heavier strength training to ease the massive strain/stress/fatigue that the gym 3-4x a week was having on my nervous system (plus spiking crazy hunger and furious sadness). I had been trying to "recomp" for 6 months, and it just wasn't happening. I was packing on both muscle *and* fat and so much inflammation and with work stress plus trying to be in a small calorie deficit, *and* perimenopause to boot, not recovering properly.
So this pivot to lower-intensity movement was so that I could enter into a calorie deficit safely and a dedicated fasting habit with as little crazy cortisol as possible. Now I'm doing 5 days of 30-40 minute lightly-weighted pilates, plus 1x 30-minute vinyasa yoga practice, and 10k steps a day (I have always done 10k steps, even while strength training). I am smallish: 5"3' / 163 and have dropped from about 130lbs (59~) to 124 (56~). My body fat is now hovering around maybe about 21.5% (it was closer to 23.5-24% when I started), but I have the genetic and hormonal predisposition to store most of my fat in the dangerous midsection, so I'm still motivated to continue my calorie deficit until I reach ~117lbs / ~53kg and maybe ~19% body fat. Then I'll start to reverse diet and increase my weights again slowly for recomp.
TL;DR: The 16:8 has been working well and delightfully. But now, 5 weeks and some fat-loss in, I am starting to struggle with energy a bit. do I eat up to maintenance for a couple of days and see if this helps matters before dropping back down again to continue? Or is there another strategy I haven't considered yet?
Your goal weight is getting closer, progress naturally slows.
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Please read the book Fast Feast Repeat! I promise you will learn so much, and you will know where to go from there:)
Oh! Great recommendation. Thank you. Shall do!
Is the audio book good or are there tables to reference?
Maybe you could try to do 14:10 for a while?
Hey! Thanks so much for sharing your journey. I will admit I cannot speak on how having female hormonal shifts affects this. I want to recommend electrolyte supplementation. I transitioned IF protocols recently and was white knuckling through some gnarly headaches and tiredness. Yesterday I finally gave into add some electrolytes to my water and sipping slowly, and it changed a lot. I know a lot of people say that electrolyte supplementation is not necessary for shorter fasts <1 day, but maybe you could try this for a couple days to see if it will help (if you're not doing this already?). Also, this is coming from my heart, but I recommend you actually take in the amount of calories your body needs but replace those calories with foods that do not spike insulin very high (foods that are not processed or refined, minimally refined carbohydrate sources at best). Your metabolism is a fire-- IF is letting your insulin levels fall, which can drain your electrolytes a little bit since insulin increases fluid retention, but it also makes nutrients from your fat cells available for use instead of food coming from the outside world. But, in a deep caloric restriction, the total energy available in the blood if you are still feeding (not in a complete fast) could be low enough to where the brain still perceives a scarce environment of energy available for burning. This could be happening if you are eating a low calorie diet that is full of refined carbohydrate sources. I only say this to protect your metabolism. It is the hormonal shifts of IF allowing for more energy availability in the blood that makes IF special. As a tangent to modern dogma, I believe that IF is not merely a vehicle for calorie restriction for the reasons mentioned above. Lastly, if you do eat more calories that are less insulin spiking, the extreme of this is the keto diet (which I don't think is absolutely necessary). I mention keto because many people who don't fast and do keto get this "keto flu" that is actually an electrolyte problem due to the massive insulin drop from the diet change independent of fasting-- more proof that fasting length isn't the only factor to be considered for if we should supplement with electrolytes. I'm sorry for my wordiness. Tldr: please consider electrolytes, and please consider not eating at a deficit BUT making sure you are eating only whole/minimally processed/refined foods. Fasting is hard enough, no need to go 75² hard! Blessings.
Grab some ketone urine test strips. When you feel light headed do a test. When you get into ketosis you can feel that light headed and might appear to be foggy. But it's quite the opposite. It's the energy your brain loves and it's not used to being so clear that it hurt. That's what I found happened to me.
Electrolitesssss drink some legit!! So critical
I’m a health care provider and saw your post about IF and the symptoms you’re experiencing. I also IF annnnddddd and am in perimenopause. I don’t think it would hurt to run your symptoms by your provider. The clumsiness, in particular, can be caused by vitamin b12 deficiency, folate deficiency, or anemia.
Where are you in your cycle? I definitely have times of the month that are harder to keep to a fast. I've read some posts on here (you could probably search it) where people talk about fasting length being more intuitive to their hormone phase, specifically fasting less right before/during your period, because your body is losing nutrients.