Food intake and activity levels have a huge effect on metabolism levels. The less food that we eat can lower our metabolism if we are making out body starve. The body will start to eat itself and cause you to lose weight. Then when you do actually eat, the body will fat that food and store it, causing you to gain more weight. Exercise and eating right is a healthy way to boost the metabolism. The more exercise one gets will increase the metabolism of the body as it works off the calories from the food eaten.