Before I answer your question, I have one of my own, Haseena. What do you consider overweight?
I ask because overweight can mean one to 50 pounds above what is considered the normal weight for an individual. This varies according to height, gender, and age.
Obesity is the killer of Americans and rare in other countries. Obesity is anyone whose weight exceeds the considered norm of 50 pounds or more.
How you eat, when you eat, this can affect your health. Bad eating and sitting all the time contribute to ill health.
An overweight person can be healthy, despite the few extra pounds, if he or she is eating an almost balanced diet and gets a few hours out of the chair doing housework, gardening or walking.
Considering the research as everyone has noted, you should determine for yourself what those studies tell you. Not take someone else's word for it.
I hope this helps answer your question. Thank you for providing me an opportunity to consider my brain health and making me think.