this tip for reversing winter weight gain. Soak up some sun to curb cravings. Without enough sunlight, your body’s production of the feel-good hormone serotonin dips dramatically. That may trigger cravings for chips, cookies, ice cream and other refined carbs, which have the power to raise serotonin levels, too, but for a price: calories. But sitting in the sun (or even a brightly lit room) for at least 10 – 15 minutes a day can do the same thing.