An analysis of overweight people found that their fat can cease to cope as it increases in size and becomes suffocated by its own expansion.
Medics at the University of Exeter examined tissue samples from patients, including those with weight problems who have undergone bariatric surgery.
Fat in obese people can suffocate and struggle for oxygen supply, due in part to the increase in the fat cells’ size.
As cells get bigger they become distressed and struggle for oxygen, which triggers inflammation in the fat tissue.
The inflammation spills over from fat tissue into the bloodstream and is eventually measurable in the circulation by a blood test.
Stressed and unhealthy fat tissue is also less able to accommodate more unused dietary energy.
With fat tissue not being able to do its most vital job, which is storing excess calories, the excess energy can be increasingly diverted from fat tissue to vital organs.
Dr Katarina Kos, from the university’s medical school, found that fat tissue is also stiffer and more rigid, and increased levels of scarring can make it harder to lose weight.
She said: “Scarring of fat tissue may make weight loss more difficult.”
Although such people can appear relatively slim, fat can be deposited in their abdomen and in their internal organs, including their liver, pancreas, muscle and the heart.
Fat can also be stored around and in the arteries causing arteriosclerosis, a stiffening of arteries predisposing people to high blood pressure, heart disease and strokes. Scarring of fat tissue has also been linked to diabetes.
Dr Kos said: “One could have very little fat below the skin and still be at risk of diabetes due to a lot of fat within the abdomen and inner organs.”
She studied the abdominal fat tissue of obese people which had become fibrous or “scarred” in order to identify what regulates this scarring and to look at how to reverse it.
She found that this molecule is more prevalent in fat tissue of obese people and that it was increased by inflammation and oxygen deprivation.
“Further research is needed to determine how to avoid our fat tissue becoming unhealthy and how protect it from inflammation and scarring,” Dr Kos said.
“There is evidence that once fat tissue becomes scarred, despite weight loss, it may not recover fully.
“We need to look after our fat tissue which can cease to cope if it is overworked when being forced to absorb more and more calories.
“As a clinician, I would advise exercise or at least a ‘walk’ after a meal, which can make a great difference to our metabolic health.“
The study, Lysyl Oxidase And Adipose Tissue Dysfunction, is published in the journal Metabolism.