Why is My Skinny Fat Worse After Losing Weight with GLP1? – Question

Hi there, Dr. Skinny Fat. As a thirty-something, I recently lost 60 pounds on GLP1 drugs. I have been very careful about proper protein intake & weightlifting to maintain muscle. Managing my weight has always been a struggle. When I was in my teens, I enjoyed playing sports, especially soccer, but I could not keep up with the competition, no matter how hard I worked. It was then that I first noticed that my body seemed to have less muscle. I am pretty sure I was skinny fat then, even though my doctor diagnosed me as normal. What is normal?

When I ask my doctor for a muscle measurement, they cannot give me one. No muscle measurement from birth, and no muscle measurement right now. How does my doctor know I am normal if they have no measurement? They did tell me that, along with fat loss, GLP1 drugs can cause muscle loss, and that is why I am now skinny fat. They said I just need to lose more fat weight and add muscle. Sorry, but, what? I just lost a bunch of fat weight and now I have to lose more fat weight to get rid of the skinny fat?

My BMI is below 24.99, but i am very skinny fat. Is the muscle under my skinny fat, and when I lose more fat weight, the muscle will show? I don’t think so. I was down around BMI 18.5 in my teen years for a time, and it didn’t reveal more muscle. Not to mention, I have lifted weights for years, but it has never cured my skinny fat. It has only helped manage it. The thing is, even though my doctor tells me my muscle levels are normal, I am quite sure I never had the muscle to begin with. How do I know for sure? My apologies, but I am not comfortable sending pictures.

Why is My Skinny Fat Worse After Losing Weight with GLP1?

Your situation is relatively common. At this time, there is no way for science/medicine to measure total genetic muscle tissue at birth or after birth — ever — let alone added muscle mass via resistance/exercise or muscle lost due to poor diet, exercise, lifestyle, and/or aging. No accurate muscle measurement exists. Even if a measurement did exist, there is no average measurement to compare it to so you could determine if you are below average (skinny fat), average, or above average. More to the point, there is no way to diagnose skinny fat, at present. Our MRI Study (1) is working on solutions.

Currently, the best your doctor, any doctor, can offer is a very rough muscle estimate — that is, a “lean body mass (LBM)” estimate — which is inaccurate at best and useless at worst. They grossly assume that all human beings are born with the same general amount of muscle tissue relative to gender and height. Our science (2, 3, 4, 5) shows that gross assumption is unequivocally false. And our MRI Study (1) will prove it once and for all.

As well, the studies that claim that GLP1 causes severe muscle loss that leads to skinny fat have no idea how much muscle tissue each study participant had before they started taking the GLP1 drug, let alone after. Because no such measurements exist. Yet, these studies pass as “science” and are parroted by doctors, medical professionals, etc.

What Really Happened – Skinny Fat & GLP1

Your reasonable observations, logic, and rationale are likely spot on. You were genetically born without the muscle tissue to begin with. Instead, you have experienced skinny fat (lack of genetic muscle) from birth. It is possible that you lost muscle tissue during fat weight loss, at least, and that has made your existing skinny fat worse. But lost muscle does not (6, 2, 3, 4) magically turn into any kind of fat, or vice versa — this is not how human tissue works.

Moreover, losing more regular white/yellow body fat will not cure (7) your skinny fat. Skinny fat is a lack of genetic muscle. Getting down to a lower BMI of 18.5 or less will not magically make the lacking genetic muscle appear. Your own experience has confirmed this fact.

Along with proper diet (8) and lifestyle (9) choices, adding muscle mass via resistance exercise (10, 11), particularly weightlifting (12), is the best way to reduce (13) skinny fat through body recomposition. However, it does not cure (4, 7) skinny fat — it only reduces it. Any muscle mass you add, you will have to maintain forever, or you will gradually return to your original genetic body composition. Including any skinny fat. No matter what nonsense claims are made on social media or elsewhere. Questions are weclome in the comments below.

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References

1. Skinny Fat Science: Scientific Skinny Fat MRI Study – Proving What Skinny Fat Is, March 26, 2025. https://skinnyfat.fellowone.com/skinny-fat-science/scientific-skinny-fat-mri-study-proving-what-skinny-fat-is/
2. Fellow One Research: Body Type Science Research Data. https://fellowone.com/category/fellow-one-research/the-four-body-types/body-type-science/research-data/
3. Skinny Fat Science: What is Skinny Fat?, July 24, 2024. https://skinnyfat.fellowone.com/skinny-fat-science/what-is-skinny-fat/
4. Skinny Fat Science: Is Muscle/Mass Genetic and How Does It Affect Skinny Fat?, November 20, 2024. https://skinnyfat.fellowone.com/skinny-fat-science/is-muscle-mass-genetic-and-how-does-it-affect-skinny-fat/
5. Skinny Fat Science: Skinny Fat is a Lack of Genetic Muscle – Beyond Normal-Weight Obesity, August 13, 2025. https://skinnyfat.fellowone.com/skinny-fat-science/skinny-fat-is-a-lack-of-genetic-muscle-beyond-normal-weight-obesity/
6. Skinny Fat Science: Is Skinny Fat Genetic?, November 27, 2024. https://skinnyfat.fellowone.com/skinny-fat-science/is-skinny-fat-genetic/
7. Skinny Fat Science: Does Starving Fix Skinny Fat?, October 1, 2025. https://skinnyfat.fellowone.com/skinny-fat-science/does-starving-fix-skinny-fat/
8. Skinny Fat Science: The Best Skinny Fat Diet, According to Science, July 29, 2024. https://skinnyfat.fellowone.com/skinny-fat-science/the-best-skinny-fat-diet-according-to-science/
9. Skinny Fat Science: The Best Skinny Fat Lifestyle, According to Science, August 14, 2024. https://skinnyfat.fellowone.com/skinny-fat-science/the-best-skinny-fat-lifestyle-according-to-science/
10. Skinny Fat Science: Best Skinny Fat Resistance Exercises, September 4, 2024. https://skinnyfat.fellowone.com/skinny-fat-science/best-skinny-fat-resistance-exercises/
11. Skinny Fat Science: The Best Skinny Fat Exercise, According to Science, August 2, 2024. https://skinnyfat.fellowone.com/skinny-fat-science/the-best-skinny-fat-exercise-according-to-science/
12. Skinny Fat Science: Resistance Training for Skinny Fat – Weight Lifting, 40 Optimal Exercises (with Images), May 7, 2025. https://skinnyfat.fellowone.com/skinny-fat-science/resistance-training-for-skinny-fat-weight-lifting-40-optimal-exercises-with-images/
13. Skinny Fat Science: How to Fix Skinny Fat, July 27, 2024. https://skinnyfat.fellowone.com/skinny-fat-science/how-to-fix-skinny-fat/