For decades, fat tissue earned a reputation as dead weight, something the body would function better without. But researchers have discovered a counterintuitive truth: losing fat can be just as dangerous as having too much of it, especially when the loss stems from genetic or autoimmune disorders that trigger abnormal fat breakdown.
The revelation emerged from a study of familial partial lipodystrophy type 2 (FPLD2), a rare condition in which patients lose fat tissue abnormally and develop metabolic dysfunction including diabetes. Understanding how this happens has forced scientists to reconsider fat's role in the body as something far more vital than a fuel reserve.
Adipose tissue, the scientific name for fat, functions as an active organ. It stores energy, produces hormones, and regulates metabolism. When fat cells work properly, they keep the body's metabolism running smoothly. When they fail, the consequences can be severe.
Elif Oral, a professor in the Division of Metabolism, Endocrinology and Diabetes at the University of Michigan, has spent her career investigating this paradox. Why does pathological fat loss trigger the same kinds of metabolic disasters associated with obesity? Working with colleagues Ormond MacDougald and graduate researcher Jessica Maung, she set out to find answers by examining the actual tissue in people with FPLD2.
Inside a Dying Fat Cell
The team created a mouse model that mimicked FPLD2 by disabling the lamin A/C gene specifically in fat cells. This is the same gene that goes wrong in human patients with the condition. They then studied tissue samples from both the animals and donated patient tissue.
What they found was catastrophic. Fat cells stopped processing and storing lipids normally. The immune cells within the tissue shifted into an inflammatory state. The mitochondria, the energy-generating structures inside cells, ceased functioning as they should.
"All of these effects come together to create this perfect environment for the tissue to be really unhealthy and eventually disappear," Maung explained.
The chain reaction matters because healthy adipose tissue does more than sit there. It manages lipids throughout the body and releases metabolic hormones that regulate blood sugar and overall metabolic health. When fat tissue deteriorates, the body loses these critical functions.
This finding reframes how doctors should think about diabetes. Most medical training emphasizes the role of beta cells in the pancreas, the cells that produce insulin. The new research reveals that fat cells themselves are central to maintaining normal blood sugar control.
"People think of Type 2 diabetes as a disease of beta cells, but it's actually a disease of fat cells, too," Oral said.
When healthy fat vanishes, the liver becomes clogged with fat that the body can no longer process properly. Blood sugar spirals out of control. The metabolic collapse can be swift and severe.
The implications extend beyond rare genetic disorders. The finding that healthy fat tissue is essential for metabolic function challenges conventional weight loss messaging. It suggests that the composition and function of the fat you have matters as much as how much you have.
The research team hopes their work will point toward new treatments. One possibility is to intervene before fat tissue deteriorates, protecting adipocytes and preventing the downstream damage that leads to diabetes and other metabolic diseases. Another avenue involves understanding which genes or cellular processes could be targeted to restore function to damaged fat tissue.
The study, published in the Journal of Clinical Investigation in 2025, underscores the value of collaboration between laboratory scientists, clinical researchers, and patients willing to donate tissue and participate in research. For rare diseases like FPLD2, patient involvement has been essential to understanding the condition and developing better therapies.
Author Jessica Williams: "This research flips the script on how we talk about fat and health, reminding us that not all weight loss is created equal."
Comments