From Healthline.com….
What are flanks?
Flanks, or “love handles,” refer to the excess fat on the sides of your lower waist and back.
Although excess can build up anywhere on the body, it often occurs in this area. That’s because the body tends to store fat around the belly. This type of fat distribution may be due to factors like genetics, hormones, or gender.
Love handle formation is also more common as you get older. Over time, the body redistributes fat from your limbs to your trunk. Your metabolism also slows down, causing weight gain.