Visceral fat cells are basically chaotic: They aren’t designed to store lots of fat for a long time, Dr. Laughlin explains, and tend to spill some into nearby organs like your liver, heart, pancreas, and skeletal muscle (which don’t normally hold fat). The ballooning visceral fat cells along with the fat in your organs can then release chemicals that set off alarm bells for your immune system, triggering a chronic state of inflammation—which ups your risk for conditions like heart disease, type 2 diabetes, and cancer. Bombarded by fatty trespassers and inflammation, your organ tissues may struggle to recognize and respond to insulin, the hormone that prompts them to metabolize sugar. To compensate, “your pancreas will work over time to pump out more insulin,” Dr. Jensen says. But “we aren’t born with infinite pancreatic capacity,” he says, so eventually, there may not be enough to get your cells to process sugar, leaving too much of it in your blood and raising your risk for type 2 diabetes. (If you have ovaries, the extra insulin could also increase your risk for or worsen symptoms of polycystic ovary syndrome (PCOS), which could impair your fertility.)
The visceral-fat-to-liver-fat pipeline, in particular, may also have an effect on your cholesterol: When your liver is overrun by fatty molecules, it creates more of a certain type of fat called triglycerides that it sends into your bloodstream, which lowers your “good” HDL cholesterol levels, Dr. Jensen says. The resulting change in lipids could lead to plaque buildup in your arteries, worsening your chances of a heart attack or stroke. Separately, with a bigger body, your heart may have to work harder to pump blood throughout it, which may increase your blood pressure and amplify these cardiovascular risks.
Fat can shift certain hormone levels in a way that drives up cancer risk.
Remember how we said fat was bioactive? Well, that’s not just about visceral fat getting inflamed and leaky. Both visceral and subcutaneous fats also contain the enzyme aromatase, which converts androgens like testosterone into estrogen. A surplus of fat could then leave you with extra-high estrogen levels, which are linked to greater risk of cancers like breast, endometrial, and ovarian—though the link with breast cancer is only significant in postmenopausal folks for reasons that aren’t totally clear. It may be that, at this time in life, “your body’s overall tolerance for estrogen is lower,” since your ovaries no longer make it, Arif Kamal, MD, MBA, chief patient officer for the American Cancer Society, tells SELF.
Another fat-created hormone called leptin can cause cells to grow or proliferate in wonky ways (which could spur tumor development), as can insulin, adds Dr. Kamal, which may be elevated in fat people because of the metabolic changes described above.
It might physically interfere with key body functions or day-to-day living.
The mass and volume of fat may pose an outsize burden on certain parts of your body, like, for instance, your joints. Over time, paired with the rise in inflammation noted above, the additional pressure could wear away at the squishy cartilage cushioning your bones, raising your risk for a type of arthritis called osteoarthritis (which can bring joint pain and stiffness)—research suggests people who are categorized as having obesity (per BMI) are more likely to experience knee osteoarthritis, in particular.
