Dietotherapy is a long-term behavior and has no effect at all in the short term. This aspect of things is mainly aimed at the elderly, who have nothing to do in their leisure time, plus they are old, facing many health problems and have practical needs in life. Anyone with a little knowledge can study for health, of course. If you can follow in the footsteps of "everyone", you will get twice the result with half the effort. Things on the Internet must be true or false. Because health care is relatively easy to do, there are really many contents and the prices vary greatly.