When you go to bed, just After taking food. The use of that food as the energy by the body is reduced and after digesting that food converts into fat.
When you sleep after late-night dinner. The mind does not calm down. And your sleep is disturbed.
After having food at night, the body goes through a similar process because the body is slowly started accumulating of glucose.
Because the food eaten just before sleeping in the night gives rise to diseases related to digestion in your body. So it also affects the normal status of your blood pressure.