When you run, swim, or bike, increase the intensity of your pace for 30-second intervals, before returning to your normal speed after. This will help you take in more oxygen and make your mitochondria, your cell powerhouses, work harder to burn energy, Mark Hyman, MD, an integrative and functional medicine specialist in private practice in Lenox, Massachusetts, and author of Ultra metabolism: The Simple Plan for Automatic Weight Loss, tells Health. A nice perk of this move: You can exercise for less time than usual and still see great results. If you slash how many calories you take in, your metabolism thinks food is scarce and slows down to try to conserve your energy, and puts the breaks on fat-burning to conserve energy, Hyman explains. To keep your metabolism revved up while trying to lose weight you’ll want to make sure you have enough calories to at least match your resting metabolic rate. That's about 1,330 calories for a 5-feet-4-inch, 150-pound, 40-year-old woman. Having more, smaller meals during the day can help you feel full, but it also might help keep your metabolism throttling. Why? Having smaller meals throughout the day can help keep your blood sugar levels in a good range, and prevent insulin spikes that can lead to weight gain. Trans fats aren’t just bad for your heart they also slow down your body's ability to burn fat. Eating trans fat can cause insulin resistance, when cells in your muscles, fat, and liver don't respond well to insulin and can't easily take up glucose from your blood, and inflammation, and both of those can mess with your metabolism.