What BMI Is Skinny Fat?

Technically, according to the initial 2016 NIH scientific definition (1, 2), skinny fat exists between a safe Standard BMI of 18.5 to 24.99 and is characterized by having too much body fat. But the latest evolving skinny fat science reveals that skinny fat is unique genetic tissue (2) that exists where genetic default muscle tissue should be, but is not. So, at what BMI can skinny fat exist?

The egregiously popular spiel up on social media, especially in eating disorder (ED) communities, is that skinny fat only exists at a very specific BMI, and can be magically starved away and cured. It cannot.

In fact, starving (calorie deficit) no less than slows metabolism (3) and causes muscle tissue loss (3), which makes any existing skinny fat tissue (thin fat, cellulite)(2) worse.

The Science – What BMI Is Skinny Fat?

Research participant 1053 (4) began their weight loss journey at an obese BMI of 32.1. They have obvious skinny fat tissue — both thin fat and cellulite (2) — widespread across their body where they should have genetic default muscle tissue but do not.

They safely lost regular white/yellow fat (common body fat/adipose tissue) down to an overweight BMI of 26.3, yet the same skinny fat tissue exists in the same places across their body where they should have genetic default muscle tissue, but do not.

Their muscle tissue did not magically turn into any kind of fat; not how human tissue works (5, 6, 7). Even if they lose more regular fat weight down to a safe BMI between 18.5 and 24.99, the genetic default muscle tissue that they are clearly lacking (does not exist, and never did from birth) will not magically appear. Nor will their skinny fat tissue magically go away.

Research Participant 1170

Research participant 1170 (8) started within safe BMI at 24.6 and is normal weight obese, experiencing widespread obvious thin fat and cellulite skinny fat tissue where genetically they should have default genetic muscle tissue, but do not.

They safely lost regular fat weight down to a safe BMI of 21.3, yet all the same skinny fat tissue exists in all the same places where genetic default muscle tissue should be but is not.

Skinny fat tissue that they have had from birth (7, 5, 6). They could safely lose more regular fat weight down to a safe BMI of 18.5 and the skinny fat tissue will not magically turn into muscle tissue or go away. Moreover, they can technically lose 100% of their regular white/yellow fat (BMI 0 – not possible) yet their skinny fat tissue will remain.

Skinny fat is unique genetic tissue (2) that can exist at any BMI.

What BMI Is Skinny Fat?

For instance, see how genetically blessed Christian Bale lost a lot of weight including obvious muscle tissue. See the clear muscle definition including 6-pack abs, while emaciated! Yet no skinny fat. Genetics.

Poor diet and exercise can cause muscle tissue loss but lost muscle tissue does not magically turn into skinny fat, or vice versa. Not how human tissue works!!! (6, 5, 7) Some people are genetically blessed and are not experiencing skinny fat tissue. Most people are not genetically blessed and are experiencing skinny fat tissue, to some degree.

If you are experiencing genetic skinny fat tissue, then you can properly add muscle mass (9, 10, 6) to reduce it along with safely losing regular white/yellow fat (3).

How Do I Know If I Am Experiencing Skinny Fat Tissue? – Scientific Body Type Quiz

As of January 2025 (2), there is no scientifically/medically approved way for doctors to officially diagnose skinny fat. Developed using the latest science, the Scientific Body Type Quiz (Official) — one of the Scientific Health Quizzes —  accurately determines if you are experiencing skinny fat tissue, where on your body, and how it affects your body shape and health including metabolism, diet, exercise, and lifestyle.

Like all the Scientific Health Quizzes, the Scientific Body Type Quiz is safe, secure, and anonymous. Accounts are free. Free Quiz options are available.

References

1. NIH, National Library of Medicine: Normal-weight obesity syndrome: diagnosis, prevalence, and clinical implications, September 2016 (Epub Jul 29, 2016), Lana P Franco, Carla C Morais, Cristiane Cominetti. https://pubmed.ncbi.nlm.nih.gov/27473199/
2. Skinny Fat Science: What Is Skinny Fat?, July 26, 2024. https://skinnyfat.fellowone.com/what-is-skinny-fat/
3. Skinny Fat Science: The Best Skinny Fat Diet, According to Science, July 29, 2024. https://skinnyfat.fellowone.com/the-best-skinny-fat-diet-according-to-science/
4. Fellow One Research: Body Type Test (Quiz) Results 1053 – Body Type Four (BT4) Female (Woman), Millennial (Generation Y). https://www.fellowone.com/fellow-one-research/the-four-body-types/body-type-quiz/body-type-test-quiz-results-1053-body-type-four-bt4-female-woman-millennial-generation-y/
5. Skinny Fat Science: Is Muscle/Mass Genetic and How Does It Affect Skinny Fat?, November 20, 2024. https://skinnyfat.fellowone.com/is-muscle-mass-genetic-and-how-does-it-affect-skinny-fat/
6. Skinny Fat Science: How To Fix Skinny Fat, July 27, 2024. https://skinnyfat.fellowone.com/how-to-fix-skinny-fat/
7. Skinny Fat Science: Is Skinny Fat Genetic?, November 27, 2024. https://skinnyfat.fellowone.com/is-skinny-fat-genetic/
8. Fellow One Research: Body Type Test (Quiz) Results 1170 – Body Type Three (BT3) Female (Woman), Generation Z, February 2022. https://www.fellowone.com/fellow-one-research/the-four-body-types/body-type-quiz/body-type-test-quiz-results-1170-body-type-three-bt3-female-woman-generation-z/
9. Skinny Fat Science: Best Skinny Fat Resistance Exercises, September 4, 2024. https://skinnyfat.fellowone.com/best-skinny-fat-resistance-exercises/
10. Skinny Fat Science: The Best Skinny Fat Exercise, According to Science, August 2, 2024. https://skinnyfat.fellowone.com/the-best-skinny-fat-exercise-according-to-science/