13 of the Best Fat-Burning Foods You Can Eat to Tone Up and Feel Great

Oranges and grapefruits are great examples of fruits with vitamins, antioxidants, and a high-water content. Kristin said that grapefruits are especially fantastic because they're lower in calories than oranges and lower on the glycemic index. It also doesn't hurt that their bitter taste can help reduce appetite. "Studies done on grapefruit demonstrated that taking grapefruit in varied forms (fruit, juice, or capsule) was correlated with significant weight loss and even greater insulin resistance in some people," Kristin said.