For every 3,500 calories you burn, you’ll lose a pound. However, it turns out that slimming down is more complex than the golden rule preached by fitness pros. Shedding pounds isn’t so precise, according to Ralph La Forge, a physiologist and managing director of the Duke Lipid and Metabolic Disorder Training Program at Duke University Medical Center in Durham, N.C.

Although weight loss does, indeed, depend upon the “calories-in, calories-out” equation, you may at times exercise without losing weight. For example, a brisk 30-minute walk burns 200 calories – only about half the amount in that bagel you ate this morning (minus the cream cheese).

In addition, gender and genes matter. Women, who store fat differently than men and have a harder time losing fat around the abdomen, tend to lose weight more slowly. And some people are just born with a faster resting metabolism, so they burn calories more quickly.

So what can you do to nudge the scale down? Keep these tips in mind.

Do exercise a little more. Gradually increase the time and intensity of your workouts to burn more calories. Just walking 15 minutes more, for example, will help you shed an additional 100 calories. 

Do work more muscles. The more muscle groups you work, the more energy your body uses. Thirty minutes of weight-bearing exercise, such as walking, hiking, dancing, tai chi and some forms of yoga, burns more calories than 30 minutes of stationary cycling or some types of resistance training. It also builds strong bones.

Do aim to burn about 1,500 calories per week through exercise. That’s the average amount recommended by the American College of Sports Medicine. Walking three miles per day over five days will do it; or call your local Arthritis Foundation office for information on exercise programs. 

Don’t reach for a post-workout snack, or you could add back as many calories as you just burned off. Drink a glass – or two – of water instead; you actually may be more thirsty than hungry.

Don’t trust the numbers. If you walk on a treadmill or ride a stationary bike, the number of calories you actually burn is often 10 to 15 percent lower than what’s displayed on the screen. That’s because the mechanical assistance of the machine allows your body to do less work – and most calorie-counters don’t take that into account.  

Don’t collapse on the couch when you get home. If you rest after a workout more than you would normally, your body slows down and doesn’t burn as many calories as it usually does.

Do keep in mind these everyday activities and how many calories they burn (for a 150-pound person):

Mopping floors (1/2 hour)                140 calories
Vacuuming (1/2 hour)                       140 calories
Ironing (1/2 hour)                              75 calories
Pulling weeds (1/2 hour)                   177 calories
Washing the car (1 hour)                   300 calories
Bagging leaves (1/2 hour)                 136 calories
Washing dishes (1 hour)                   152 calories
Rearranging furniture (1 hour)          450 calories
Indoor painting (1 hour)                    204 calories
Grocery shopping (1/2 hour)            130 calories
Walking (1/2 hour)                           100 calories
Sleeping (8 hours)                             50 calories