The Scary Truth About Weight Loss and Activity Level

The Scary Truth About Weight Loss and Activity Level

Walking or taking a fitness class a few times a week may not be enough to help you lose weight.
by Martica Heaner, Ph.D., M.A., M.Ed.,

Q. I exercise four days a week and haven’t noticed any weight loss. I work from home part-time and at an office part-time. When I’m at home, I walk for at least 30 minutes in my neighborhood. On the days that I’m at my office, I take a fitness class such as Pilates or body sculpting. I eat pretty well, but I can’t seem to lose weight. What am I doing wrong?

A. Perception is not always reality, and that’s often the case when it comes to determining how active we are or how much we eat. The tendency to over-report exercise and under-report food intake can dramatically skew the results from an exercise or diet program. This is such a problem that researchers who study diet and exercise troubleshoot to find ways to ensure that study participants adhere to the prescribed diet or amount of exercise. For example, they’ll often monitor the participants’ activity or food intake in several ways to ensure that the reports match, and they might give regular reminder calls and/or e-mails to ensure that the subjects are not skipping workout days. In some carefully controlled studies, they’ll even go so far as to collect and weigh uneaten food so they will know exactly how much was consumed.

You exercise more but get lazier

On top of the under- and over-reporting tendency, there’s a phenomenon of psychological compensation. Some people who exercise give themselves a “reward” and become more sluggish during their nonexercise time, or they have an extra few helpings of food or a dessert, rationalizing that they can do so because they exercised.

Doing enough exercise usually works

If you’re doing a whole lot of exercise, eating a little more or moving a little less probably won’t counteract the large calorie burn you may have accrued. So, if you’re working out every day, and your workouts are long or intense forms of cardio such as running for an hour or walking or cycling for two, you may burn an extra 500 or 600 calories. Unless you are eating a lot of junk food, you might still eat a little more, but it wouldn’t be that easy to eat up the extra that you burned off.

This is why the current consensus of all evidence-based guidelines for physical activity state that, to manage body weight, a person needs at least 60 to 90 minutes of moderate to vigorous physical activity every day. Less than that is good for you, but it probably won’t affect your weight very much. (If this sounds like an impossible amount, keep in mind that it’s our modern environment that makes us so sedentary. In rural or nonmodern societies, humans move constantly when they work.)

Minimal amounts of exercise may not make a dent in your weight

If you’re doing the minimum amounts of activity—such as a 30-minute walk or a low-calorie-burning workout like Pilates—then even though the exercise is undoubtedly good for your health, it may not have a big impact on your energy balance.

This seems counterintuitive; if you burn more calories through exercise, that should lead to weight loss. Technically speaking, it will. Burning any extra calories will lead to weight loss, but the fewer you burn per session, per week, per month, the longer it will take to see measurable results. And that’s assuming that everything else in your life is held constant—you don’t eat more or move less. So, if you burn only 150 to 200 calories from a workout session and you do this only a few times per week, it’s easy to erase (or surpass) the energy deficit you created with an extra glass of wine or two, a candy bar or an extra hour spent watching TV.

How active you really are

An important variable to factor in on top of how much exercise you get in, is how “active” you are all day. Your daily physical activity can trump your exercise routine. Do you sit for eight hours nonstop, or do you take stairs every hour and get up out of your chair every few minutes? Do you stand more than you sit?

You mention that you work from home. If you are mostly at a computer and if you don’t leave your house except for an occasional half-hour stroll, chances are that you are very inactive—more than you might think. So your walk may simply be bringing you up to some minimal level of overall daily activity, and not adding the big boost of extra activity that you might assume.

An office job tends to be sedentary, and some more so than others. Of course, getting to work may get you up and moving a bit, especially if you walk to and from parking spaces or public transportation. One reason why people in New York City tend to be less obese than the rest of America is because walking is part of daily function. It’s nearly impossible not to walk for at least 15 to 30 minutes a day to get to the subway or to run errands.

Likewise, how much people eat can vary. If you work at home, you may have easier access to food. A few extra crackers or cookies here and there can toss in a few hundred more calories, which can hamper weight loss or lead to weight gain even if your main meals are healthy.