The Utter Ridiculousness of the 5-10% Weight Loss Recommendation

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The idea that people can gain “clinically meaningful health benefits” by losing 5-10% of their body weight is ubiquitous and ridiculous. Sometimes it is recommended as a way to improve general health, to reduce cardiometabolic risk factors, or to improve a specific health condition. This piece is, essentially, the third in a series about this phenomenon. You can find the other two pieces, in which I wrote in depth about ideas, and a study that tested it, here. Today I want to look at the sheer folly of the basic math and logic of this because this 5-10% weight loss idea doesn’t just defy research, it defies logic and math.

The recommendation is that those who are “overw*ight” or “ob*se” based on the (deeply flawed!) BMI scale should be advised to lose 5-10% of their weight.

Just as a reminder (and this is covered in depth in my previous piece) this number was arrived at by attrition. So, this is not about medical recommendations changing due to new and better science. Rather, the recommended amount of weight loss has dropped precipitously over the years as intentional weight loss interventions continuously failed to create the recommended amount of weight loss. Also, those who are still clinging to the weight loss paradigm continue to lower the bar - as you may remember the Academy of Nutrition and Dietetics (ANAD) hit a new low (literally and figuratively) when their proposed guidelines suggested just 3-5% weight loss.

Let’s break this down using some real numbers (content note: I’ll be talking about exact heights and weights and weight loss so please take care of yourself and, of course, feel free to skip the rest of this piece to keep yourself safe.)

We’ll start with a woman who is 5’3 and weighs 300 pounds. She has type 2 diabetes and her A1C (a measure of her average blood glucose level) is 7.1.

This person’s BMI is 53.1 (according to the NIH calculator.) which makes her “class 3 ob*se” (again, this is a nonsense category, on a nonsense scale, but it is a categorization system and scale that is adhered to by those who push the 5-10% weight loss recommendation.)

So, she goes to the doctor and is told that she should try to lose 5-10% of her body weight to improve her blood sugar/A1C. If, assuming - without much evidence - she could lose 10% of her body weight, and in the short time before she almost certainly gains it all back, it would leave her at 270lbs. At that point her BMI would be 47.8 which is still “class 3 ob*se” So, using their own scale, she has not only not moved out of the “ob*se” category, she has not even moved out of her current “class” of “ob*sity”. If an amount of weight loss that doesn’t make any change on this scale is considered a success, what is the point of this scale?

But it gets more ridiculous.

Let’s say we have a woman who is 5’3 and weighs 270lbs (again, “class 3 ob*se”). She has type 2 diabetes and her A1C is 7.1.

So, she goes to the doctor and is told that she should try to lose 5-10% of her body weight to improve her blood sugar/A1C. But wait, our 300 pound patient was told that getting to 270 pounds would improve her A1C. But this patient, who weighs 270lbs has to lose 5-10% of her body weight to improve her A1C? The ridiculousness is starting to reveal itself, but let’s keep going with this.

Assuming (without much evidence) that she could lose 10% of her body weight, and in the short time before she almost certainly gains it all back, it would leave her at 243lbs (which would leave her at a BMI of 43 which is still “class 3 ob*se”).

Let’s say we have woman who is 5’3 and weighs 243lbs. She has type 2 diabetes and her A1C is 7.1…

You get the idea.

Remembering that this 5-10% weight loss recommendation is for anyone who is “overw*ight” or above on the BMI chart, this recommendation would be given to any 5’3 person at or above 140.9 pounds.

But wait, there’s more.

Let’s say we have a woman who is 5’3 and weighs 140.9 pounds (again, “overw*ight”). She has type 2 diabetes and her A1C is 7.1.

At that BMI, she should get the old 5-10% weight loss recommendation. Except, if she loses just 0.1 pounds, she would move into the “normal” weight category and thus, not be subject to the recommendation. So does she need to lose 5-10% of her body weight to improve her A1C? Or is she just one tenth of one pound from improving her blood glucose?

Let’s take this home. A woman who is 5’3 and 140.8 pounds comes into the doctor’s office with Type 2 Diabetes and an A1C of 7.1. She has the exact same diagnosis and A1C as the 300 pound woman, but since her BMI is in the “normal” range she doesn’t get the weight loss recommendation, she gets ethical, evidence-based medical interventions.

This is, to write in the colloquial, absolutely bonkers. And it is recommended to up to 70% of the population. This has to stop. The truth is that thin people get all the same health issues as fat people, but fat people are constantly, uncritically, told to lose weight to treat or prevent health issues that people at lower weights already get.

And that’s before we consider that this whole “lose 5-10% of your body weight” nonsense isn’t based on clinical studies, but on the weight loss industry moving the goalpost for “clinically meaningful weight loss” and healthcare practitioners (some of whom are part of, or take money from, the weight loss industry) taking it as truth and parroting it back while actively ignoring the research that suggests that it’s not this (small, likely not sustained) weight loss that creates the health changes but, rather, the behavior changes that preceded both the small amount of weight loss and any health improvements.

Patients of all sizes deserve ethical, evidence-based medicine that is grounded in research, math, and logic and this 5-10% weight loss recommendation does not qualify.

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More research and resources:
https://haeshealthsheets.com/resources/

*Note on language: I use “fat” as a neutral descriptor as used by the fat activist community, I use “ob*se” and “overw*ight” to acknowledge that these are terms that were created to medicalize and pathologize fat bodies, with roots in racism and specifically anti-Blackness. Please read Sabrina Strings’ Fearing the Black Body – the Racial Origins of Fat Phobia and Da’Shaun Harrison’s Belly of the Beast: The Politics of Anti-Fatness as Anti-Blackness for more on this.