Hi there,
I’m on my 3rd day of trying out IF, 18-6 (eating window 2PM-8PM). I’m 5’9”, 205lbs, and consuming a little over 1,000 kcal a day. According to TDEE, my maintenance cals are around 2,310kcal. I work an office job and and don’t do much activity other than climbing stairs and walking. I’m curious if anyone else has had success with such a similarly low calorie intake? Thanks!
That’s unhealthy for someone who’s 5’9. What’s the rush? Losing weight slowly is proven to be more effective than fast weight loss. I’d eat around 1500 calories a day at your height to lose around 1-2lb a week
I found that when I started fasting and actually for a bit of time after, that I wouldn’t be hungry at all and would consume lower calories than my TDEE. I didn’t want to force myself to eat to the point of making myself sick, and as others sagely pointed out, the body will level off eventually. If you have fat to lose, your body is getting the energy it needs from there too. Now, mind you, if this goes on for more than a few weeks or months, it depends on the individual, you may want to have a higher calorie day.
Just sharing my own experience. The point is not to chronically undereat, it’s to get healthy and hone the benefits of fasting. That said, the focus shouldn’t be in forcing yourself to eat when you don’t feel like it.
Give it some time, and let us know how it goes! Good luck!
Edit: typo
I think it is too little in the long term, but if you have some 1000 calorie days here and there it’s fine. I generally average out my calories over the week and go by that because my hunger level changes from day to day. Some days I’m not very hungry or I’m super busy and just don’t have time to eat much and those will be around 1000 calorie days, other days I am more hungry and I’ll eat closer to 1600. In the end I just try to make sure it all averages out over the whole week to around 1300 per day, which is my calorie goal for weight loss.
I’ve personally not had success with so few calories. I’ve tried that in the past - last a couple days, feel horrible and give up. Maybe it’s not reaching daily protein needs, but I just end up feeling weak, irritable and lethargic.. as well as being so hungry that I’m just constantly thinking about food, like obsessively. I had to go for more calories to make it sustainable. Yes you can white-knuckle your way through 1k/day but imho that just sounds miserable and a failed diet waiting to happen.I’m 5’8, 207 lb and my daily intake is 1600-2000 cals, though I am pretty active. If you’re not working out you probably need less but I’d bet more than 1000. I think it would make the diet easier to stick to. Hope this helps!
By way of reference, the prisoners at Auschwitz received around 1200 calories a day. I’m sure you know what they ended up looking like.
So, you may be able to do 1000 calories once in a while, but you should definitely not think it’s a healthy thing to habitually do.
I’ll be contrarian here and say that you could do 1000 calories some/most days but you should cycle in higher calorie “spike” days to help boost metabolism, stabilize hunger hormones, keep you satiated, etc. So, since 1000 cal is incredibly low, I would say do a couple days of that and then do a couple days of 1500, and maybe even one day of 1800 to really give yourself a boost. That would require a lot of mental effort so you could also just say you’re gonna have several days where you eat specifically 500 extra calories. Look up calorie cycling online. There are some good examples of ways to plan this throughout the week. I used to do it and I just spiked my calories on weekend.
Note: this isn’t cheat days or meals, the spikes are still at or below TDEE. Just looking at a week rather than daily calorie intake and expenditure and alternating. The worst possible thing you can do is rebound and then start eating more than what you used to eat because you’re freaking out about being so hungry. This is why it’s hard to lose weight. Being hungry sucks. Fasting makes it easier.
If you are eating 2 small meals 500 kcal during eating window, that might not be enough for you to feel satiated. Calorie restriction that much is generally not advised on IF as you body will slow your metabolism as well making fat loss slow or plateau. My recommendation would be to eat slightly under your budget..so 1800-2000 and consider longer fasts that will allow your body to fat adapt and start burning that for fuel. The real power of IF and fat loss comes from the baselining of insulin levels slowing your bodies metabolic tools to switch to fat burning ketosis…and calorie restriction plays minimal to no role in that process.A ton of other variables play into the whole equation as well that are specific to you…i.e. diet (huge impact), gut micro biome, insulin resistance, other health issues.
Someone on CICO sub told me that its quite less & I should consume 1500 at least everyday. For context, my height & maintenance is about the same as you & I had posted a screenshot of my consumption chart when my consumption was 1300-1400 cals for like 3-4 days in a line.
It is not enough to continue to feed all of the functions your body requires. You can do it for a while, and not suffer any noticeable issues, but eventually there will be a point that issues will arise. Not only that, but that is a good way to end up “skinny-fat” and I do t know anyone who’s goal is to be skinnyfat.
https://www.healthline.com/nutrition/signs-of-not-eating-enough#hair-loss
For reference, I’m 165 and consume 1800-2100 per day, with 160-180 grams of protein. I started in the high 230s and have been maintaining 165 for a couple of years now.
If you are above a healthy weight then 1000 calories a day is fine. I’ve done it and I felt great and lost 1kg+ a week. In fact there is a medical case study of an obese man who had zero calories for more than 12 months under medical supervision and was in good health throughout with vitamin and mineral supplements. But If you are under weight you need to get 2200 calories a day or you could become quite ill
This is not necessarily an endorsement, but I went several months at 1000 or less per day and had no problem. I wasn’t trying to restrict that much per se, it just kind of worked out that way. Over a two month timeframe I went from 14:10 OMAD. Once on OMAD, I struggled to eat more than 1000. I somehow even build modest muscle during this time. Again, not an endorsement. It was probably too fast. Im probably eating 1200-1600 per day now and maintaining well.
For reference: 43M, 5’11, SW 235, CW 180, 5ish months on IF.