Does exercise help you lose weight?

As people continue to pursue New Year's resolutions, often there are efforts to improve on lifestyle habits with a common goal of weight loss. For many people, the first instinct is to go to the gym three or four days per week, hopping on a treadmill for an hour or even just talking the family dog out for a few more walks each week. However many people realize, sometimes quickly, that their valiant and sweaty efforts haven't led to as much weight loss as they had hoped.

So is exercise not effective for weight loss? Is it a waste of time and effort?

First, exercise provides many health-related benefits and is one of the most important countermeasures you can rely on to prevent chronic disease and reduce overall risk of mortality. However, sometimes the effectiveness of exercise for weight loss is oversold, and people may overestimate how effective it will be toward their goal of losing weight. Therefore, it's important for people to understand how to incorporate exercise into their weight management plan in a way that doesn't lead to one step forward and two steps back.

Overestimated caloric deficits

Being regularly active and taking part in structured exercise activities are ways to expend more energy throughout the day — often referred to as burning more calories. A negative energy balance — more commonly referred to as a caloric deficit — is required for sustained weight loss over time. However, exercise may not lead to as big of a deficit as you may think.

Activity trackers and fitness watches often overestimate the amount of calories burned during exercise. Instead of 1,200 calories burned during your 45-minute elliptical session tracked on your fitness watch, it may be closer to 400 to 700 calories, depending on your intensity levels. This may lead you to miscalculate your target calories for the day and ultimately mislead you in how many calories you can consume throughout the rest of the day.

Daily habits

One of the reasons exercise may not meaningfully reduce body weight is because people often take part in other behaviors that offset this action when they're not exercising, thus sabotaging their goal of weight loss.

Some people tend to eat more after exercise, either driven by increased hunger or as part of a behavioral reward construct. For example, a person may add in a snack or splurge on a dessert, likely preceded by the inner monologue of "I've earned this." This type of action essentially negates any additional calories the person expended during their hard-earned trip to the gym.

Research also has found that people often are less active throughout the day after a bout of activity. Again, this type of behavior may reduce the potential for a daily caloric deficit, as a person may expend less energy throughout the remaining hours of the day. They actually burn fewer overall calories than if they hadn't exercised at all.

Dietary changes

Researchers have found that dietary change is a more effective and time-efficient strategy for promoting substantial weight loss and maintenance over time. Let's face it, making time to work out throughout the week is hard. It takes time and discipline to change your clothes, go to the gym, exercise for an hour, shower and head back to work or home for the day. Not only is it hard to do once, but to follow this routine five to seven days a week over several weeks to months is even harder.

This is a lot of effort to burn an extra 400 to 600 calories during exercise, especially if you negate these hard-earned and burned calories by indulging at your next meal. What took you over a few hours of time with travel, preparation and exercise can be offset in minutes by making the wrong choice in the kitchen.

Strength training

The type of exercise you do is important, as well. Strength training is an effective form of exercise for building lean body mass, which can improve weight loss and overall appearance. This improved body composition often is a common goal of many people who set out to lose weight.

Yes, losing weight can be important, particularly if you are overweight or obese, but it is just as important to focus on the type of weight you lose. You should emphasize maintaining lean body mass with strength training, rather than only focusing on losing weight. Strength training also helps conserve functionality as you age by preserving muscle tissue, strengthening bones, improving balance and preventing injuries ― if done properly.

So is exercise for weight loss pointless? No, absolutely not.

Exercise can be an effective lifestyle modification for weight loss, especially when used in conjunction with dietary modifications to ensure a consistent caloric deficit over time. It is worth repeating that exercise also has mental and physical benefits that can profoundly affect health and overall quality of life in addition to serving an important strategic role in losing weight.

Andrew Jagim, Ph.D., is an exercise physiologist and sports nutritionist in Sports Medicine in Onalaska, Wisconsin.