You see advertisements everywhere promoting exercise programs that will help you lose weight. Six weeks to shredded, 30 days to a bikini body and 12 weeks to fitness are headlines invading social streams. Images of lean, muscular and scantily clad tanned bodies extract guilt as you sit on the couch and eat potato chips. Do these 5 exercises and in 60 days you can look like this, too.
There is no debate that exercise is good for you. It’s an important component of any healthy lifestyle. It helps your body to function more efficiently, build and maintain strength and ensure long-term mobility. When you exercise you send cues to your body that you intend to keep using it and it responds by making sure those functions are in tip-top shape. But how effective is exercise for helping you lose weight? Can you eat what you want and use exercise as a way of compensating?
At work we teach new team members that managing customer expectations is key to a successful outcome. Tell your customers a project will take eight weeks and then deliver in six and you have happy customers. Tell them it will take four and deliver in six and you are dealing with an unhappy crowd. Same delivery time, different expectations. Having realistic expectations is key to maintaining ongoing motivation and faith in the process.
I believe this principle is especially true when it comes to our own fitness and health. Promises of a quick fix almost always end up failing to meet expectations. When our expectations aren’t sufficiently met we lose faith in the process all together. This six-week shred didn’t work. That level of fitness is unrealistic. That body is not achievable. I’ll never lose weight. I’ll never get in shape. Why bother?
If you spend any time in a gym you have probably seen that one person, slightly overweight with a round belly, that shows up every week without fail, puts in a tremendous amount of effort during workouts but never seems to change. They still look exactly the same. The exercise doesn’t seem to have any impact. It doesn’t make sense. They are working so hard. How is it nothing has changed?
The Experiment: Can I Use Exercise to Lose Weight
How effective is exercise at inducing weight-loss? Can you really eat whatever you want and exercise will compensate?
To answer these questions I ran an experiment. I kept an exercise diary for a full week documenting the stats from my activity tracker. At the end of the week I will tally the total number of active calories burned during exercise. We can use this number to estimate the potential impact my exercise might have on my ability to lose weight.
Is the expected impact in line with your expectations?
I’m using the Apple Watch activity tracker calibrated according to the manufacturer specifications. For more on activity tracking accuracy you can check out this article on CNET.
Before I give you the results let’s put a few facts out there regarding how the body loses weight. Like it our not weight loss is a factor of calories. The only way to lose weight is to consume fewer calories than your body uses. Sorry folks you can’t get around it. There are healthy ways to do this and there are unhealthy ways to do this. I’ll save that discussion for later but for now that is the principle we are working with.
There is a mathematical formula to weight loss. If you consume 3500 calories more than your body burns (surplus) you will gain one pound. If you consume 3500 calories less than your body burns (deficit) you will lose one pound. Your body doesn’t wait to hit the magic mark of 3500 calories and then instantly lose or gain in one pound increments, it is a cumulative process.
The variable that throws most people off is the fact that while the calorie requirement for gaining and losing weight remains the same the number of calories that your body will burn does not. The amount of calories that your body burns will change from day-to-day depending on how active you are and your overall body composition. The only way to know the exact number of calories that your body burns is to spend hours in a lab being monitored. Most of us, probably almost all of us, are not going to do this. This is where weight loss can go awry. It is really easy to over or underestimate your body’s calorie burn.
Beware the Variables
A number of factors impact the calories you burn each day. When you weigh more you burn more. If you have more lean muscle mass you burn more. Alternatively if you weigh less you will burn less. If you lose muscle mass you burn less. My husband is larger than I am. He burns more calories during the day if he isn’t doing anything. Even if we run the same track he burns more than I do. Life isn’t fair. Suck it up buttercup.
Think about this for a second. As you lose weight you typically lose body fat and muscle mass. The more weight you lose the smaller you are and the less muscle mass you have the fewer calories you burn. As you lose the weight you must continually adjust your calorie intake to account for your lower weight to continue experiencing weight loss! As if it wasn’t hard enough!
So what happened? In total 10 workouts that equaled slightly under 6 hours of activity burned a total of 1,528 active calories over 7 days.
Let’s assume that I managed to eat the exact number of calories that my body burns without the added exercise (not easy to do but we are simplifying the math). With six hours of exercise I would lose less than half a pound a week (.44 pound).
I think this is worth repeating. That’s not even half of one pound of weight loss in one week. That’s less than 2 pounds a month. The amount of calories I burned in 6 hours of activity is less than a California Turkey Club Toasted Sandwich with a side of fries at Chili’s. One dinner cancels out the entire weeks exercise induced weight loss.
What if you weren’t able to keep your calories in check and eat exactly what your body burns? What if you went over and ate what you wanted? Would you be losing weight even though you exercised for six hours of the week? The answer is no, you just can’t burn that many calories to compensate when your diet adds in extra turkey club sandwiches.
Even if you could keep your calories in check if you are staring down the barrel of a 40 or 50 pound weight loss goal only losing less than 2 pounds a month is not so encouraging. Suddenly that 30 day to shredded program doesn’t feel so realistic. Why bother to exercise if it won’t have that much of an impact?
Resetting Expectations: Weight Loss When Exercise and Diet are Combined
If you have thoughts like these it’s time to change your strategy and reset your expectations. Let’s imagine instead of eating the exact number of calories that your body burns in a day you eat about 300 calories fewer (create a deficit). 300 calories is equivalent to about one Venti White Chocolate Mocha Frapucino at Starbucks.
A deficit of 300 calories a day results in slightly over half a pound a week (.6 pound) a week. I know, I know that’s about as hop-skipping-do-dah inducing as less than half a pound a week. It gets better.
What happens when you put the two together? Combine a 300 calorie a day deficit (that’s one big fancy cream filled whip cream topped coffee) and the calories burned from exercise and Bam! You would now lose weight at the rate of a pound a week. For my rate of burn that would be a loss of 4.42 pounds in one month. If you weigh more than I do you could burn more. Losing almost five pounds a month is quite a bit more promising than less than two.
Put that in terms of 12 weeks and that’s more than 13 pounds in three months! Before the end of the year that would be in the range of a 50 pound weight loss.
Can Exercise Really Impact Your Ability to Lose Weight?
Can you lose weight through exercise alone? Possibly, but as we learned here the loss is slow going. If you are operating under the assumption that you can eat what you want then the likelihood is probably not. That six-week to shredded? Only if you are looking to lose a pound or two.
What is happening with that person at the gym that’s going the extra mile but isn’t seeing change? More than likely they are making the mistake of assuming that exercise is enough. Exercise is a great way to improve overall health. On its own the power to influence weight loss is smaller than most people understand. It doesn’t burn enough to cancel out a significant overage in calorie consumption.
What exercise can do is amplify the benefits from sensible and nutritious eating. It can keep you from having to take drastic measures in cutting out calories that leave you feeling starved. And did I mention, the benefits to your health far outweigh the calorie burn it provides.
Impacts of Exercise on Weight Loss
The key to success is all about managing expectations. An exercise only approach will help to improve your body’s functioning and shape. It will not create significant weight loss. Knowing how exercise and food impacts your body will help you to make more good decisions than bad for a longer period of time without getting frustrated with the process.
The best news is that once you do lose weight your exercise habits will make it easier to keep the weight off. If you are burning 1,528 calories a week through exercise you get flexibility in your calorie intake to help you ward off-putting the weight back on. Life is about balance and moderation. You can’t go back to consuming the amount of calories that you were before or you’ll just start putting the weight back on!
Food For Thought
Below are some helpful resources that can help you learn more about finding your own personal calculations.
- Learn about your resting metabolic rate. This is the minimum number of calories you need to survive.
- Get estimations for your total daily calorie burn. I use My Fitness Pal . But here’s another link in case you don’t like creating online accounts. Remember, these are estimates!
- Knowing your current calorie intake. Even if you don’t keep a food diary every day use a calorie library to look up some of your favorite meals. It’s shocking!! Again, I prefer My Fitness Pal but just in case here’s another online library.
- Now you do the math. [Calories Burned] – [Calories Consumed]. If you get a positive number you are losing. If you get a negative number you are gaining.
You can read the full diary using the link below. I left it as is so please forgive the typos and grammar. Even if you’ve been staying fit for years I highly recommend keeping an exercise diary for a week. It was a great experience to see my good days and my bad ones. It reminds me to focus on maintaining flexibility with my schedule, cut myself some slack and don’t be discouraged by a bad day.