Your parents are probaly confused as everyone is trying to cash in and turn weight loss into a product to sell so there is lots of misleading info floating about. At the end of the day weight loss boils down to expending more energy than you consume. The form of exercise is irrelevant. You can get a good sweat up in the garden, vacuuming etc. the same as in the gym. I am planning on renovating my house as my main form of exercise for the next 6 months.
"Unknowingly, we plow the dust of the stars, blown about us by the wind, and drink the universe in a glass of rain."