Why I think BMI is actually BS

I started to write this after having a handful of clients this week who have been told by PTs and GPs that their BMI indicates they are obese and need to lose weight. These clients have been given various protocols to lose weight from shake diets to ongoing 1200kcal diets. None of these practitioners have been trained in nutrition or considered the effects of this dietary advice. The effects of the comments and the advice lead to stress, revisited weight trauma, self-esteem loss, and unhealthy eating practices and relationships to food. Let alone the impact these diets can have on the gut microbiome and hormonal health.

What is BMI?

It is body mass index, an equation designed by an astronomer and statistician to categorise people using a bell-shaped curve to represent height and weight in people. Put simply it measures weight in relation to height. It then pops people into the category of underweight, healthy, overweight, obese, morbidly obese. These classifications and labels can lead people to undertake all sorts of dieting extremes to get to the “ideal” BMI. And as a side note, it’s well over 80% of people who diet to lose weight, gain the weight back and often more. There are many reasons for this, but that is a whole other post.

Why I think it’s BS

It doesn’t give any indication of health. It doesn’t take into consideration factors including the person’s lifestyle, body fat, muscle mass, waist measurements, waist to hip ratio, bone density, physical activity, blood pressure, hormone levels, glucose, and lipid levels. And it rules out body diversity.

A high BMI can classify a person as obese, yet they could be a very fit and healthy person with good muscle mass.

Thin does not always equal healthy. Fat does not always equal unhealthy. It’s not that simple. What is incredibly unhealthy is people who are constantly aiming to achieve an ideal that is driven by diet culture and marketing. And these goalposts change…constantly. Over the last 60 years, the trend has ranged from the hourglass figure in the 50s, Twiggy in the 60s, a waif of the 90s, athletic body of the 2000s, and the booty bangers of late. I mean seriously do people need any more pressure about how they should look from their respected GPs and PTs?

It’s not your body that needs fixing, it’s the sole use of BMI as an indicator of health that needs to go in the bin