I am a fitness instructor. If you want to show the vest line, you have to keep the body fat rate below 20%, which requires you to do aerobic exercise for large muscle groups on a regular basis and strictly manage your diet. Aerobic exercise should not be less than 5 days a week, with each time lasting about 50 minutes, and the best effect is to keep your heart rate within 50%~75% of your maximum heart rate (220- age). The diet structure should be adjusted to a high-protein, low-fat and low-carbohydrate structure, and enough protein intake should be ensured every day to avoid muscle loss. You can consult me if you have any questions.