The time required for boys to reduce their body fat rate from 25% to 15% varies from person to person, because it depends on their physical condition, sports experience, training plan and diet control. Generally speaking, this process may take several months to a year.

In order to effectively reduce the body fat rate, it is suggested to adopt the following training and diet strategies:

1. Training: Make a systematic training plan, including strength training and aerobic exercise. Strength training helps to increase muscle mass, improve metabolic rate and promote fat burning. Aerobic exercise, such as jogging, swimming and cycling, can increase cardiopulmonary function and accelerate the burning of fat. It is recommended to train at least three to five times a week, and the training time should be controlled at 60 to 90 minutes each time.

2. Diet: control the daily total calorie intake to ensure that the calorie intake is lower than the calorie consumption. Mix protein, carbohydrate and healthy fat reasonably, and avoid foods high in sugar, fat and salt. It is suggested to follow a professional diet plan to ensure a balanced intake of nutrients and meet individual needs.

In short, it takes a long time to reduce the body fat rate. Systematic training and healthy diet are the key to achieving the goal. Please follow the advice of professional coaches and keep a positive attitude and patience.