We tend to think of body fat as the enemy of metabolic health. A new study is a reminder that healthy fat is essential — and that losing the wrong fat can trigger diabetes.
Researchers at the University of Michigan, writing in the Journal of Clinical Investigation, studied familial partial lipodystrophy type 2 (FPLD2), a rare inherited disorder marked by abnormal fat loss and uneven fat distribution — and a high rate of diabetes.
The paradox lipodystrophy presents
People with lipodystrophy develop severe insulin resistance, high triglycerides, fatty liver and diabetes — the metabolic profile associated with obesity, in people who have very little fat.
That combination is what makes the condition scientifically instructive. It demonstrates that metabolic disease is not caused by fat quantity as such, and it points to a different explanation.
The prevailing account is overflow. Fat tissue exists to store lipid safely, in cells built for it. When storage capacity is exceeded — whether because there is too much lipid or too little tissue to hold it — the excess accumulates in liver, muscle and pancreas, where it interferes with insulin signalling and cellular function.
Obesity and lipodystrophy arrive at the same place from opposite directions: one exceeds a normal capacity, the other has almost none.
What goes wrong
Using mice with the lamin A/C gene switched off in fat cells, and human tissue from patients, the team watched healthy fat cells become inflamed, lose their ability to store lipids, and eventually disappear.
That collapse disrupts energy storage and hormone production — the metabolic jobs fat tissue quietly performs.
“All of these effects come together to create this perfect environment for the tissue to be really unhealthy and eventually disappear,” said researcher Jessica Maung.
Why lamin A/C
The gene encodes a structural protein of the nuclear envelope — the membrane enclosing the cell’s DNA — which seems remote from fat storage.
The nuclear lamina is not merely structural. Chromosomes are anchored to it, and where a region of DNA sits relative to it influences whether genes there are active. Disrupting the lamina can therefore alter gene expression broadly.
Mutations in the same gene cause a strikingly varied set of conditions — muscular dystrophies, cardiac conduction disease, a premature ageing syndrome, and this lipodystrophy — which is difficult to explain if the protein only provided structure, and more explicable if it shapes how different cell types regulate themselves.
Fat as an endocrine organ
The reference to hormone production points to a function often overlooked.
Fat tissue secretes signalling molecules that act throughout the body. Leptin reports energy stores to the brain and regulates appetite and energy expenditure; adiponectin improves insulin sensitivity in liver and muscle.
Without adequate fat tissue those signals are absent. Very low leptin produces persistent hunger regardless of energy status, which contributes to the metabolic disturbance independently of the storage failure.
Leptin replacement is used in severe lipodystrophy for precisely that reason, and it works — direct evidence that the hormonal deficiency, not only the storage deficiency, drives the disease.
Why the inflammation sequence matters
The order the team observed — inflammation, then loss of storage function, then cell death — suggests intervention points before the tissue is gone.
Once fat cells disappear they are not readily replaced, so a therapy preventing the collapse would be far more valuable than one attempted afterwards. Identifying inflammation as an early step raises the possibility of interrupting it.
Why it matters beyond a rare disease
“This is really underscoring the importance of healthy fats in keeping metabolism intact,” added Prof. Elif Oral.
The findings sharpen a counterintuitive point: metabolic health depends not just on how much fat you carry, but on whether that tissue is healthy and functional.
What treatment looks like now
Management of severe lipodystrophy is instructive because it addresses consequences rather than cause, which is the gap this research aims at.
Leptin replacement is the main disease-specific therapy, correcting the hormone deficiency that fat loss creates. It improves glucose control, lowers triglycerides and reduces liver fat, and it does not restore fat tissue.
Everything else is conventional metabolic management: insulin, frequently at very high doses because resistance is severe; drugs to lower triglycerides, which can reach concentrations that risk pancreatitis; and treatment of the fatty liver disease that develops in most patients.
Outcomes remain poor despite that, because the underlying problem — nowhere safe to store lipid — persists throughout.
What would change the picture is preventing fat cell loss, or generating new fat tissue. Neither is currently possible, and identifying the sequence by which cells fail is a prerequisite for the first of them — which is the practical significance of watching the process unfold rather than only observing its endpoint.
That has bearing on common metabolic disease, where the same variability appears — some people with substantial obesity remain metabolically normal, while others develop diabetes at modest weight. Fat tissue quality plausibly explains part of that difference. This is laboratory research, not medical advice.