3. The Type of Workouts you Do: While any exercise is good for the body, some activities do burn more calories than others. Weight-bearing activities1 like running, aerobics or walking, burn more calories because gravity requires your body to work harder. When doing non-weight-bearing exercises like cycling or swimming, there isn’t as much gravitational stress on the muscles, which means fewer calories expended. What you can do: Non-weight-bearing activities do have advantages. They’re less stressful on the joints and you can often do them longer, which could make up the difference in calories burned with weight-bearing activities. However, cross-training with impact activities, if you’re able to do that, will not only work your body in different ways, it also helps build stronger bones and connective tissue. 4. Mechanical Efficiency: You probably never thought that being good at an activity would mean burning fewer calories, but that’s exactly what happens when you exercise consistently. Think about the first time you tried a treadmill or some other cardio machine. You probably felt awkward, holding onto the rails and worrying you might fall off. Over time, the movement became so natural, you didn’t have to think about it anymore. As your body became more efficient, you stopped wasting energy on unnecessary movements, which leads to fewer calories burned. What you can do: Mechanical efficiency is actually a good thing. By cutting down on awkward movements, your body works more efficiently, which helps protect you from injury. 5. Exercise Compensation: Something else we don’t often consider is how exercise affects our activity2 for the rest of the day. If you do a tough workout and then take a nap or skip an afternoon walk, something you wouldn’t normally do, you’re burning fewer calories. Exercise can also increase your appetite, causing you to eat more calories which can also sabotage your weight loss goals. What you can do: If you start an exercise program, keep a food and activity journal to get an idea of a normal day for you. Resting more or eating more are things we often do without being aware of it post-exercise. Keeping a simple log of your activities will help you make sure you’re getting the same amount of activity, even with your workouts. If you're exhausted after every workout, that may be a sign you’re overdoing it. You want to keep a little gas in the tank after most of your workouts. 6. Body Mass: Another irony with weight loss is that, the heavier you are, the more calories you’ll burn with exercise. For example, a 200-lb pound person can burn about 400 calories during 30 minutes of stairclimbing, while a 125-lb person burns about 250 calories doing the same thing. As you lose weight, your body expends less energy to move your body around, which means you’ll lose weight more slowly. This is one reason why losing those last few pounds3 can be so difficult. What you can do: First, remember that losing weight is a good thing, even if it means the weight loss slows down over time. Second, as you lose weight, you may need to recalculate4 how many calories you need and how many calories you’re burning. Adjusting the numbers as you go can help you stay on track with your weight loss and avoid plateaus. 7. Genetics and Gender: While we control many of the factors involved with weight loss, there are some things we really can blame on our parents: Genes and gender. Our genes often determine resting metabolic rate, muscle fiber types and genetic responses to different foods, all of which can affect our ability to burn calories and lose weight. Your body type5 does play a role in your ability to lose weight, as does your lifestyle. Gender can also affect weight loss. Women usually have more body fat than men and their bodies respond differently to exercise, which can change the rate of weight loss. What you can do: Recognize that there may be genetic factors that affect how quickly you lose weight. While you might inherit certain genes from your parents, your eating and exercise habits can make a difference. The only way to know what your body is really capable of is to try. Following a complete exercise program6 and watching your calories is the best way to find out what your body can really do. It can be frustrating when you start exercising and don't see the results you're expecting. You may start wondering: "What am I doing wrong?" Knowing there are other factors involved can help you be more realistic and, perhaps, encourage changes to your workouts to get more out of your program. If you're distracted and discouraged by calculations that don't seem to add up, remember that they're only numbers. They don't reflect the tangible results you may be experiencing such as feeling better, having more energy or simply having a better day-to-day life.