Researchers at the Harvard T.H. Chan School of Public Health found that people who trimmed the deep fat around their organs kept the health payoff long after their trial ended, and in many cases long after their weight came back. The team followed hundreds of adults from earlier diet and lifestyle trials for up to 16 years.
Every 10 percent reduction in visceral fat achieved during the original trials was linked to a 28 percent lower risk of developing type 2 diabetes a decade later. The association held even in participants who had fully regained the body weight they lost. The cardiometabolic findings were published in June 2026 in the journal Circulation.
A companion analysis, published in March 2026 in Nature Communications, tracked participants for up to 16 years and found that those who accumulated the least visceral fat over time scored highest on cognitive tests and showed higher total brain volume and gray matter volume.
Why this fat behaves differently
Visceral fat is the deep, firm fat packed around the liver, intestines and other abdominal organs. It sits apart from subcutaneous fat, the soft pinchable layer just under the skin. Only visceral fat drains directly into the portal vein, which carries blood to the liver, and that anatomy gives it an outsized influence on cholesterol, blood sugar and inflammation.
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Harvard Health has previously noted that visceral fat makes more of the proteins called cytokines, which can trigger low-level inflammation, a risk factor for heart disease and other chronic conditions. The tissue also releases a precursor to angiotensin, a compound that constricts blood vessels and pushes blood pressure up.
That biology helps explain why the scale can lie. Two people at the same weight can carry very different amounts of visceral fat, and the one with more of it faces higher odds of type 2 diabetes, fatty liver disease and cardiovascular trouble.
What the Harvard team saw when the weight came back
The striking piece of the new work is what happened after the diet was over. Participants who had lost visceral fat during the trial did not fully regain it, even when their body weight rebounded. Their long-term risk scores for cardiometabolic disease stayed lower than would be expected from their current weight alone.
Iris Shai, adjunct professor of nutrition at Harvard T.H. Chan School of Public Health, led the research. The team reported that a Mediterranean-style, carbohydrate-restricted diet rich in polyphenols, paired with regular physical activity, was particularly effective at shrinking visceral fat depots.
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The evidence for what actually works
For readers who want to act on this, the best-supported tools are unspectacular. A pooled analysis of controlled trials found that each 30 minutes per week of aerobic exercise was associated with a small but measurable drop in visceral fat, with training beyond 150 minutes per week at moderate intensity or higher needed for clinically meaningful reductions.
A separate three-month dietary intervention study of 175 adults, published in Frontiers in Endocrinology in June 2025, reported that participants who lost at least 5 percent of their visceral fat area had significantly higher odds of improvement in waist circumference, HDL cholesterol, triglycerides and HbA1c compared with those who lost none.
None of this is a promise of a shortcut. But the Harvard findings suggest that the effort to shrink deep belly fat, even a modest amount of it, may pay dividends years after the diet plate is cleared. Anyone with existing metabolic or cardiovascular concerns should discuss diet and exercise changes with their doctor before making them.
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