It slows it down temporarily. If you ever get into a longer fast you start to feel cold when you would normally feel fine. This is your body’s self-preserving. You can counter this by working out. Your metabolism goes back to normal when you start eating.
70lbs down is huge congratulations! As you lose weight your TDEE goes down. Research shows IF does not lower metabolism anymore than traditional dieting. At a certain point you need to add more to your lite exercise. Any kind is fine as long as it’s regularly done. Walking, casual biking, light weights, dancing, yoga etc.. are all great options to just keep active.
To increase metabolism you need cardiovascular exercise or build muscle, but going this path you would need advice from a doctor since you’ve pointed out problems with metabolism just to make sure it’s safe for you.
Ok. So everyone will tell you that it doesn’t. Even studies have said that. However, I am going to give you my experience. It’s not scientific but has been my experience.
My whole life, I always lost weight very quickly when I went in a diet. It was no problem as long as I stick to my diet. In 2016, I first got to know about fasting. I started it right away and lost quite a lot of weight. It was ok for some time. I did OMAD for years. I still do actually. Sometimes doing longer fasts as well.After a while maybe about 2, 3 years, the weight started to go up and I gained everything back. It’s been a few years that fasting doesn’t work for me anymore. Since about 2020, I cannot lose any weight past the water weight through fasting. It’s impossible. I can be eating nothing for days and I still stay the same weight.
So in my opinion, don’t do fasting as a routine everyday, and you would be fine. If you make it a routine every day , your body will slow down your metabolism. I don’t care what studies say. Because mone have been on doing fasting consistently for years. The most I have seen has been on fasting for a few months.
I would say that metabolic adaptation happens to the body when its not getting enough calories to sustain itself or BMR which is the base calories that a persons body would need to survive, so while doing IF its good to stick to maintenance calories. IF isnt food restriction, its time restriction so eat the foods that you like in moderation.
When you stay in a deficit of calories for example when you increase the calories the metabolism will increase because it now has energy coming in that it can store and digest.
Eat under 2000 calories a day of whole foods…no processed foods….for life…(IF should help you stay in that calorie range) you will hit and maintain your ideal weight eventually…as long as you are moderately active….
It’s really that simple…either you want the above lifestyle or not…if you do, great, no worries you will hit your ideal sooner than you think….if you don’t, that’s fine as well, just accept the consequences….
Either way, make a choice, accept it and what it means and move forward with your life, focused on more important things….
Podcast episode explains relationship between fasting, calorie restriction and METABOLISM