1. Don't starve—or stuff—yourself.
We rely on hunger-regulating neurons in the brain to notify us when we've had enough. Now it turns out these neurons have another duty: Researchers at the Yale School of Medicine found that in mice, these neurons can actually encourage fat to turn brown. The study, published in the journal Cell, found that eating too few calories prevented white fat from turning brown, while eating just enough to satisfy hunger—prompting the action of the neurons—turned white fat to turn brown. Other research shows that eating too much can do harm, as well: Not only does overconsumption increase white fat, but it also results in interferes with brown fat's ability to burn calories.
2. Eat an apple. 
Photo by An apple a day may just keep the doctor and fat away: Researchers at the University of Iowa found that ursolic acid (found in apple peels, which gives apples their sheen) boosted brown fat in mice—even when they were fed a high-fat diet. 3. Exercise. 4. Turn down the thermostat. Photo by Sheer Photo/Getty Images When the weather outside is frightful, there may be a fat-burning benefit: One study, published in the Journal of Clinical Investigation, looked at 12 young men with lower-than-average amounts of active brown fat who were asked to sit in a 63-degree Fahrenheit room for two hours a day over the course of six weeks. They burned an extra 108 calories in the cold compared with normal indoor temperatures. Even better, after six weeks their bodies were burning an extra 289 calories in the cold, prompting researchers to hypothesize that the exposure to lower temps increased the activity of a gene that converts white fat to brown. 5. Stimulate your body's melatonin production.
Moving your body may seem like a no-brainer when it comes to burning fat. Research suggests why so many people see success when they hit the gym on a regular basis: One animal study published in the journal Disease Models and Mechanisms found that working out triggers the release of an enzyme called irisin that prompts white fat cells to convert to brown. Newer research presented at the 2013 annual meeting of the American Diabetes Association found that exercise can prompt the browning of fat in men, with the benefits still increasing after 12 weeks of training on an exercise bike.
Not only does the hormone melatonin help regulate our sleep-wake cycle, but research published in the Journal of Pineal Research found that in rats, it increases the presence of "beige" fat, which is similar to brown fat in its calorie-burning capabilities. While you might be tempted to take a supplement, experts say it's best to stimulate your body's own natural production by avoiding nighttime exposure to light from TVs, computers and other screens, getting sunlight exposure during the day, and loading up on melatonin-rich foods, including almonds, tomatoes, tart cherries, cardamom, and coriander.
