How long will it take to drop 20 kgs?

√ ( 2 * h / g )

h = height from which it's dropped

Keto/paleo : 2-3 months Intermittent fasting(14+ hrs) : 6-7months

Excersise / calorie deficit / HIT - intense take 6-7 months ; casual you may never achieve that goal.

Why don't you like your child?

4-5 months if you do - strength training and calorie deficit food intake.

Much slower with just focusing on cardio.

Personal experience - about 1 year. Mix of healthy eating, no alcohol, 5 times a week gym.

Didn’t find a need to be super aggressive to do in 3-4 months. Calories deficit makes you grumpy+need energy for day job.

But you do you….

20 weeks at 1kg/week tracking. It is possible if you go calorie deficit

I took 3 months exact with strict diet and Gym for 6 days/week

With a strict diet and aggressive workout, you can drop 1kg per week, but after 2 -3 months you won’t be able to see such a drop in your body weight. So, I believe it would take 9–12 months for a person with a good metabolism.