What does excess weight do to your inflammation levels?

Excess weight keeps the immune system in a state of persistent, low-grade activation. Multiple studies consistently show that people with excess weight have higher levels of inflammatory substances in the blood. This inflammation is not acute like an infection, but creeping and sustained. It increases as the excess weight becomes more severe: at a BMI above 40, measured values are clearly higher than in mild overweight.

Fatty tissue itself is a major driver of this inflammation. As fat accumulates, immune cells infiltrate the fatty tissue. These cells cause local inflammation there, but also release substances into the bloodstream that affect the entire body. At the same time, levels of adiponectin fall -- a hormone that fat cells normally produce and that has an anti-inflammatory effect. With excess weight, less of it is produced, and the body also responds to it less effectively.

Two other mechanisms make the picture more complex. First, excess weight disrupts the gut microbiome and makes the gut wall more permeable. This allows bacterial substances to enter the bloodstream more easily and fuel the inflammatory response. Second, excess weight often leads to fat accumulation in the liver. This fatty liver disease in turn contributes to greater systemic inflammation, which then worsens the liver disease further.

This chronic inflammation does not come without consequences. It increases the tendency for blood clots to form and plays a small but measurable role in the elevated risk of depression seen in people with excess weight. A pro-inflammatory diet (high in processed foods, low in fibre) makes things worse.

There is also good news: twelve weeks of strength training three times per week measurably reduced the inflammatory markers CRP and TNF-alpha in men with excess weight, and raised adiponectin. Combined upper- and lower-body training produced the strongest effect, but training of just one body region was already beneficial.