How do I lose up to 20 pounds in like a month?

You don't unless you expect to get sick and put it ALL back on and then some inside of 2 months.

20 lbs in a month is excessve weight loss for a 4 week period. 1 or 2 per week can be achieved without negative health consequences.

The reason being your body WILL genetically sense a starvation period and ratches DOWN the bodies metabolism rate to survive when food is scarce... both making it harder to lose any weight but also far easier to put even more back on because it takes time before the body will speed its metabolism back up.

the best way to loose weight is eating every two hours to get your matabilism up... eat 2 oz of protein every two hrs... wheath only chicken, ground turkey salmon or tuna in can makr sure water is in it or 2 oz egg white... also breakfest you want to 2 0z protein and 1/2 cup carbs snack 2oz protein 1/2 cup friut lunch 2 oz protein 1 cup vegys 1/2 cup carbs snack same as first snak dinner 2 oz protein 2 cups vegys 1/2 cup fruit.. carbs eat either rice corn sweet potato or reg potato
make sure you eat all fresh fruits vegys if you eat anything canned or box its bad for you.. same with sugar and salt if you can stick to this you loose a lot of weight I lost 35 pouns in one month some day I lose almost an average of 2 pounds a day at first it takes all water watight off us big girls we have 25 to 50 pounds water weight on us... 80% is what you eat and 10% is genetics and only 10% is excersice so don't kill yourself at the gym