1. Too Much Fueling

Many everyday exercisers chow down on energy bars, sports drinks, and recovery bars that should be reserved for elite athletes, says Cedric X. Bryant, PhD, vice president of educational services at the American Council on Exercise. “People think they’ll supply magical strength, when all they primarily provide is calories. You can easily eat and drink 700 calories for a 200-calorie workout,” he says. “Stick to a simple piece of fruit or some nuts and water if you need a snack.”

2. Once-and-Done Attitude

Many folks mistakenly believe that 30 minutes of exercise on the treadmill is license to take the elevator, park in the closest space, or sit on the couch the rest of the day. “Exercise is cumulative. The more active you are, even when you’re not ’exercising,’ the better results you’ll have,” says Bryant. “Your body is meant to move a lot. So, avoid thinking of exercise as something you do for only half an hour.” There are lots of ways to stay active:

Take the stairs at work instead of the elevator.Park a little farther away from the mall or grocery store entrance.When you go out for lunch, choose a restaurant or carry-out several more blocks away, or just simply go out at lunch and walk 10 minutes in one direction and then turn around and walk back.If you live in a city and take public transportation, get on one or two stops farther than usual, or get off a couple stops before your destination so you have a little walk either before or after work.

3. Intensity Overload

High intensity is a good thing, but a little goes a long way. “People often think that if they’re exercising, they have to work as hard as they can all the time,” says Bryant. “Then they quit because they hurt themselves or they can’t keep it up.” Instead, exercise at a moderate intensity that you can sustain for 45 minutes. You’ll be more likely to stick to it. Or investigate interval training, where you punch up the intensity for a short periods of time between more moderate exercising. (Check out these interval training tips.)

4. Driven to Distraction

A little diversion such as TV can make exercise time go faster, but too much detracts from your workout, explains Bryant. “Any activity that requires too much concentration, such as reading a novel or a long article, demands your focus, so you slow down physically.” The better solution: Find something that helps you engage your workout. “High-energy music is one of the best choices.” (See what fitness experts listen to with Pick A Pro Playlist.)

5. Rewards Outweigh Effort

“Most people who use food as a reward take in more calories than they’ve expended,” says Bryant. If you’re going to use dessert or a nice dinner as your “carrot” to keep going, then reward yourself less frequently, he suggests.  “Once a month, if you’ve exercised consistently, go to your favorite restaurant, and get whatever you want. For more frequent rewards, stick to CDs, clothes, and other nonfood items.” MORE: 5 Workout Myths That Mess With Results