You can't lose weight by just starving yourself until you're skinny because your body has a starvation response.
When your body constantly digests food, it supplies your brain with glucose. Your body is made to be digesting food almost all the time.
If you're digestive system is not making glucose because you haven't eatan in a long time, your body will break down something called glycogen. Glycogen is stored in your liver and your muscles and it can be broken down in your liver to make glucose for your brain.
Your endocrine system will start releasing a lot of different hormones that gets picked up by your liver and your digestive system when your liver is breaking down glycogen. When this happens, you will feel a lot of pain and feel unpleasant. You will get headaches and a huge urge to eat.
You can ignore this pain though, it will not leave you writhing in agony. It just makes you want to eat. If you don't eat, your body will start the starvation response.
After not eating for 1.5 days to 3 days, your body will have no more glucose in your digestive system or liver. Your body will now starting metabolizing fatty acids, and your brain will start metabolizing ketone bodies. Fatty acids and ketone bodies is not as good as glucose for energy so your metabolism will slow down because there is less energy. Your body will soon starting digesting your fat but this happens VERY slowly.
To stay alive, your body needs at least a little glucose but your body is running off mostly fatty acids and ketone bodies. Normally, you need about 200g of glucose a day to live. It drops to 30g a day when your body starts the starvation response. To get that little bit of glucose your body will start metabolizing proteins. Proteins are amino acids and it can make glucose out of it in your liver. So your body will begin eating its own core structures.
Your body has to make at least 10g of glucose a day from protein. To make 1g of glucose in your liver, your body has to break down 3g of protein. So that means you lose about 30g of protein a day and it mostly comes from your muscles.
Yes you can lose weight by starving yourself, but it's the slowest and most painful way to do it. Your body will break down and digest your own muscles, which will hurt a lot. And it takes a long time so you have to endure that pain for a long time.
If you want to lose weight easily, this program will help you do it.