Simplify the following text for a Grade 8 native English-speaking person.
Original: Yo-yo dieting or Yo-yo effect , also known as weight cycling The term `` yo-yo dieting '' was coined by Kelly D. Brownell , Ph. D. , at Yale University , in reference to the cyclical up-down motion of a yo-yo .
Simplified: Other words for this activity are yo-yo dieting or weight cycling .