focus on body type instead of on healthy behavior - fat-shaming does nothing to promote health.
As I've written before, studies have shown that body shape is not necessarily a determining factor in health. Recently, a ew study on physical activity and lifespan revealed that people who went for brisk walks for 150 minutes over the course of a week (or an equivalent exercise) added about 4 years to a person's lifespan across all BMI levels. On the other hand, a normal BMI in an inactive person was associated with a lifespan about three years shorter.
A different study suggests other motives for fat-shaming: weight intolerance may be driven by what we see. Project Implicit explored bias towards fat people and found that the "visual diet" of observers affected their beliefs about the people they saw. The more participants saw a particular body type, the more apt they were to be tolerant of people with that body type, and the inverse was also true. Unfortunately, this also held true for doctors, who showed bias against heavier people.
One issue may be that BMI numbers can be a very good tool for assessing health trends in populations of people, but is not a very good tool for assessing individual health. Unfortunately, seeing high BMI numbers correlated with high rates of certain diseases could certainly cause confusion. Clearly, there needs to be more education about the appropriate use of this measure.
While we don't have definitive answers about obesity, how it works, and how it affects health we do know that everyone, regardless of body type, needs to stay active and eat well. Let's focus on that message.