Normal, too normal, so is the endurance of ordinary people. Twenty minutes is definitely a bottleneck, so am I, so for those who want to lose weight by going to the gym regularly, the coach will advise them to combine jogging with jogging, running with walking, and some people simply walk for an hour. Of course, for the effect, you can add a slope when walking (if your treadmill has this function).
It is really bad to eat before running. Before doing aerobic exercise for a long time, you should not only eat, but also drink water in moderation. It is best to eat half an hour to an hour before exercise. Of course, don't overeat. If you do yoga, don't eat for two hours before and after exercise.