Does IF lose its potency over time ?

Hey everyone, I started IF as a convenience and weight loss goal back in July 2019. I completely shifted to 18/6 (eating window 6PM - midnight) one day and it was awesome. I did go back to eating lunch over some months depending on work or personal situations. Not eating until six was still the main goal but I was way less serious about it and mainly over the last 2 years and a half the IF was respected. I lost a lot of weight during the first months and was really happy with IF, but over the last few months I ate a bit more out of the eating window (and possibly higher calories globally too). Right now I'm going full on again, but it doesn't seem so effective as before, so I'm wondering about the effects after a long period of IF. I'm not very physically active either but I'm planning on using a bike and maybe pick up some kind of combat sport or cardio lessons. More info : I went from 97kg to 85kg (216 to 187 lbs) Apologies for the borked english, I'm from Belgium (French speaking part)

Answer

What you’re experiencing is not that IF is less potent, it’s that weight loss becomes more difficult the more you lose.

To maintain a body weight of 216lbs, you must eat roughly 2300 calories a day. So if with your intermittent fasting you are eating 2150 calories, you will be losing weight.

However, 2150 happens to be the amount of calories required to maintain weight of 187lbs! So if you continue at this level, you will not lose weight.

IF is a tool, one that is used to consume less calories than you burn.

If you are stuck, your options are:

Eat less calories either by counting or by increasing your fasting window or being more strict.
Burn more calories by exercising while not eating any more

Also, it won’t help with weight loss but lifting weights helps build muscle which makes you appear fitter, since muscle weighs more than fat.

Answer

I wondered the same thing…I got back to strict fasting, for me it was 20-22 hrs, after a long summer season of fun(Eating and drinking) and it wasn’t working like before so after some Jason Fung reading I went to 42 hr rolling fasts and have had great success. Experiment with it.

Answer

Hi! Yes like the other poster said it makes sense that it wouldn’t be “as effective” as before because you are perhaps closer to your goal weight. Especially if you’re at a lower weight. IF is healing for the body, but if you are using it as a tool to lose weight, than you must think of it like weightlifting. A beginner utilizing weights that are challenging for them at first will become stronger and. But if they just use the same weight all the time, than over time that weight will no longer be challenging and their body just gets used to it and they aren’t progressing but just maintaining what they have. You either need to increase the reps, sets, and/or weight to make it challenging for the body again and keep gaining strength/muscle. So to me is like intermittent fasting and weight loss. While you may be getting healing, other benefits from the 18/6…perhaps you are just used to it now and you need to decrease your eating window and maybe try 20:4 or even OMAD (one meal a day) to get your weight loss going again. Or Ike someone said eating every other day (ADF) But don’t be discouraged if you don’t see the same fast results like you did when you were at a higher weight…because the closer you are to your ideal weight, the “slower” your weight will be. Anyways! Just try for a smaller eating window and like you said increase activity. Best of luck!