I have several people in my life that have told me that IF is tough on the body in the long term. And not to do it. Feel free to counter the point being made with positive things , so I can talk to them about the good things it provides!
On a positive side, autophagy is linked to longevity and the 2016 Nobel Prize winning research links the positives of autophagy with fasting: https://www.bluezones.com/2018/10/fasting-for-health-and-longevity-nobel-prize-winning-research-on-cell-aging/
I could see the “you’re starving yourself” camp of nay-sayers thinking extended fasting is dangerous, which it is. Intermittent fasting is not extended fasting though.
Explain why you shouldn’t IF (or the downside of it). I guess if I had to come up with something: You lose flexibility to eat whenever you want. On vacation, maybe your family likes to have an early big breakfast at the hotel and get ice cream mid-day and tapas for a late dinner. Well, you wouldn’t be eating all day like that on your IF plan.
But that’s not even a fair point, because you can take a break from IF if you want, and it does not undo the good you have done. (In contrast, I’ve heard that with a keto diet, you have to STAY keto in order to continue to see benefits.)
I don’t know. I started when I read The Obesity Code by Jason Fung, and he makes a lot of good, scientific arguments as to why IF is very good for your body, especially if you have been obese for awhile (and therefore may have insulin resistance). OP, if you read that book, you will be LOADED with pro-IF arguments! He addresses medical, social, and financial reasons.
IF results in most people under eating. Doing this to long can result in down regulation of thyriod, testosterone and many other hormones leading to loss of energy, low sex drive and temperature regulation. It can’t also cause disordered eating patterns. Alternating between bingeing and extreme restriction.