Be realistic, your current weight is not suitable for running at all. Theoretically, as long as the weight exceeds 75KG, it is not suitable for running. Because it will cause excessive wear of hip, knee and ankle, this wear is irreversible.

Your current running speed is 3 kilometers in half an hour, which can basically be replaced by fast walking.

Exercise intensity is very important for reducing fat. Heart rate is usually used to reflect this index, which is very important for reducing fat. It is best to control the heart rate during exercise in the range of 50%~75% of the maximum heart rate (220 years old) for fat reduction. Followed by exercise time. You can start with 30 minutes at a time, but eventually you must reach 50 to 60 minutes at a time.

After starting exercise, the calf thickens because of muscle congestion. As long as you get used to it, or stop exercising, you can return to your original state.

Aerobic training such as jogging or brisk walking won't grow muscles at all. Only strength training can promote long muscles.