Losing weight is often associated with eating less of certain foods, but a relatively recent study shows that people who add more omega-3s to their diet may shed more calories.
Researchers in Japan found that oil rich in omega-3 fatty acids turned “bad” fat cells into healthy ones that burn calories
. That’s great news for people who are in their 40s and older, as “good” fat cells start to decrease around middle-age.
The findings may explain why people who eat a Japanese or Mediterranean diet rich in fish generally lead longer, leaner lives.
Professor Teruo Kawada, who led the study at Kyoto University, said
“We knew from previous research that fish oil has tremendous health benefits, including the prevention of fat accumulation. We tested whether fish oil and an increase in beige cells could be related. People have long said that food from Japan and the Mediterranean contribute [sic] to longevity, but why these cuisines are beneficial was up for debate.
Now we have better insight into why that may be.” 
When the scientists fed oil containing fatty acids to mice, the rodents gained 5-10% less weight and 15-25% less fat after 4 months compared to mice not given the supplement.