Ageing is the hidden trigger behind expanding waistlines, says study

Causes of belly fat: Muscle mass naturally decreases with age. As muscle fades, fat-producing cells become more dominant, and fat takes up more space in the body (Image: Canva)

Increasing belly fat in middle age is common, but new research shows it’s not just about eating more or moving less. Scientists have discovered that ageing changes how your body creates fat, especially around the waist.

A study published in Science Daily suggests that certain stem cells in your body, called adipocyte progenitor cells (APCs), start acting differently as you age. The study by researchers at City of Hope and University of California, Los Angeles, says that when  you're young, these cells stay mostly inactive. But in middle age, they start producing fat cells more actively, especially in the abdominal area.

This isn’t just fat building up from food. It's your body creating new fat cells because of changes in your biology. The researchers found that this process is triggered by a signaling switch called LIFR (leukemia inhibitory factor receptor). It turns on in older adults and tells your cells to make more belly fat. This was confirmed in both mice and human tissue samples.

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5 cellular reasons ageing expands your waistline:

• Dormant fat stem cells become active: As you age, previously inactive fat-producing stem cells start multiplying and creating new fat cells.

• CP-As appear and increase fat production: Researchers identified a new type of age-specific fat stem cell called CP-As. These cells form only in older adults and are programmed to produce fat, not just store it.

• LIFR signaling triggers fat creation: The LIFR pathway becomes active with age. It sends signals to CP-As to start making more fat, especially around the belly.

• Muscle loss gives fat more space to grow: Muscle mass naturally decreases with age. As muscle fades, fat-producing cells become more dominant, and fat takes up more space in the body.

• Fat production happens even with a healthy lifestyle: Ageing cells keep producing fat, even in a young, healthy body. This means age alone can cause fat gain, regardless of diet or exercise.