We feel like sleeping in mid-noon after a meal break at work place. People cannot resist their sleep and lie down on the desk.
These post launch issues are common to all bodies. These problems are not harmful for some extent.
Metabolism is the process energy goes in caloric intake and that energy utilized by the body.
Hormones makes brain to feel fullness of stomach and blood sugar increases while insulin produced to break these blood sugars into energy makes us sleeping.
Moreover, one such hormone is serotonin that induces sleep.
If you are obese, the calories you take in are not utilized by having more physical and mental energy. Instead, stored as fat considered as metabolic problem.