4. The faux pas
Coasting on your cardio

The facts Sticking with the same aerobic workout can sabotage your results as much as pushing too hard. To truly boost your fitness (which enables you to burn more calories with less effort), you need to venture outside your comfort zone a couple of times a week, to the point where you're somewhat winded and can feel your heart pounding.

The fix Instead of zoning out or doing moderate-intensity cardio all the time, mix in some high-intensity intervals twice a week. For instance, after warming up for 10 minutes on the treadmill, increase the speed or incline for 30 seconds to 1 minute, then recover with 1-3 minutes of easy-to-moderate exercise. Keep alternating for 10-20 minutes, then cool down. You also may want to do longer high-intensity intervals--say, 5 minutes--where you don't push quite as hard as you do on the shorter ones.