Literally, the meaning of the first sentence means that people don't want to get sick, so they should eat less and keep their stomachs empty. So eat reasonably and don't overeat. If you eat when your body doesn't need to supplement nutrition, it will increase the burden on your stomach and intestines, and it is easy to be overnourished, which is not good for your body. Its realization is like this for many people. They always eat snacks and so on after meals, and eat too much. So now there are more and more obese people. So pay attention to your diet.
The second sentence means that if you want to live a long and healthy life, you can't have shit in your intestines. The defecation here means that you haven't defecated for several days, which is what people often say. If excreta is not discharged in time, it will be fermented by bacteria to produce harmful substances, which is not conducive to health. Besides being bad for intestinal health, gastrointestinal health will also be affected, and even other digestive tissues will be affected. Therefore, we must develop the habit of regular defecation.
In fact, in order to keep our health, we must pay attention to our usual living habits, which is good for our health. Moreover, forming good living habits is also very beneficial to yourself.