Stick to losing weight for 20 days, and your body shape will change greatly. However, these changes may vary from person to person, because everyone's body is different. Generally speaking, if you stick to a healthy diet and exercise habit, you may see some obvious changes, such as:

-Lose weight

-Reduce body fat

-Increase muscle mass

-Improving cardiovascular health

Of course, these changes may take longer to show up. If you want to see the effect faster, you can consider increasing exercise or changing your eating habits. However, please remember that losing weight is a long-term process that requires patience and perseverance.