I listen and I see. There are many especially females on the yoyo style of eating. I share the frustration, I too have experienced this behavior, and for several years.
There is a difference in calorie deficit and starvation. With calorie deficit you can follow through with your daily routine including working out. With starvation you can follow through with tour daily routines with easy to fall asleep because your body requires fuel and it is coasting on empty fuel. Also expect medical issues of course this can happen anytime.
For the love of yourself and those that love you PLEASE no starvation. Find an app to assist with monitoring your intake or we can chat about two great nutrition plans for healthy lifestyle, catered to your level of fitness.
Know that a change in nutrition should be for a lifestyle. Let’s stop the yoyo, focus on nutrition and cheers to the changes in the new you.