Eating a small snack before a run can increase your speed and endurance. Make sure your snack provides protein, carbs and anitoxidants that can help repair your muscles.If you eat a small portion of something with protein a few hours before your main meal can help curb your appetite, stop you from eating too much and lower your calorie intake.Pre-run try a banana with honey. Post-run snack try a 5-ounce Greek yogurt with a cup of sliced strawberries.For weight loss have 8 ounces of chocolate milk and some high-fiber cereal.