Metabolism refers to the process that converts food into energy. Your metabolic rate is the rate at which you burn calories. The metabolic rate varies from person to person and is affected by various factors like genetics, eating habit, age, gender and depending on the number of calories you eat and the number of calories you burn through your daily activities. If you have a sluggish metabolism, there could be many possible causes like may be you are on a low calorie diet, eating sugary and processed food, you are on fasting or very inactive or suffering from underactive thyroid. Whatever may be the reason, eating right food can speed up metabolism and increase the energy level and also accelerate the fat burning process and help you lose weight in a healthy way. Incorporate these nine foods in your diet to increase your metabolism.