A new study found that participants whose body mass indexes (BMIs) went from the "obese" range in early adulthood down to the "overweight" range by their midlife halved their risk of an early death.
However, weight loss after midlife didn’t significantly reduce a person’s risk of early death. In fact, a study published last year found that weight loss in middle and older age "was significantly related to increased mortality risk”. Although, this likely because weight loss later in life is often a sign of worsening health.