Hi Artsygirl, Welcome to forum.

One reason I can think of is, your body needs certain amount of energy to keep it going. In non-IF diets, they tend to restrict calories everyday, so I think they recommend not going down below this number. But this way of dieting is not sustainable for long term.

I don’t think you should be concerned about not getting enough nutrients, since in IF, you only restrict calories on 2 days (which works to 20% of total weekly intake) and you eat normally (on any food you like) to maintain your TDEE (you can find tools online). So on 5 days if you eat healthy you won’t miss out on any nutrients your body needs.

IMO, The basic idea of any diet is to eat less to lose weight, but unlike other diets IF is not hard to do. And apart from weight loss (which in my view is a side-effect) health benefits and overall fitness is what motivates me to keep going.

I am down about 15 pounds in 3 months and with improved blood results.

All the best.