This myth is false.
Applicants to the MD Program at the University of Toronto are not required to complete each year of study with five FCEs, equivalent to a full course load. The requirement to have a full course load in each year of undergraduate study (excluding summer terms) only pertains to calculation of the weighted GPA (wGPA). The wGPA automatically applies to all applicants who have completed three years of study with each year of undergraduate study being on a full-time basis with a full course load.
Admission GPA is calculated using your results from full-time studies. For the purposes of calculating your GPA, you will need to have completed at least one year of undergraduate study as a full-time student (with a minimum of three FCEs per year).