Dark chocolate
If you have a sweet tooth, take heart: Not all chocolate is off limits. “Good quality dark chocolate (anything above 65% cacao) is actually very good for you,” explains Middleberg. Like avocados, dark chocolate contains healthy monounsaturated fatty acids, which may help speed up metabolism. Just watch your portions: To indulge while keeping calories in check, Middleberg recommends having a piece “the size of a dental floss container.”