Updated: Apr 7, 2019
Exercise is one of the best things you can do for your body, your mind, and your emotional health so I’m never going to knock it or discourage it, but one of the biggest mistakes I see people make when they’re trying to lose weight is to focus on exercising more, which is a strategy that can backfire. Before we get to the reasons why, let me say this: If you’re looking to lose weight this year and you’re heading into your workouts for the sole purpose of burning tons of calories, I’m giving you permission to exercise a little bit less. Instead, find activities that excite you and that you’d enjoy doing without any link to weight loss or calorie burning. A big to key to a successful healthy lifestyle program is to find ways to move that you enjoy because that makes you more likely to continue doing them!
Calories in, calories out
You’ve heard it before: Weight loss is a matter of calories in vs. calories out. There’s some truth to this, but it’s really oversimplified. Up to 80% of the calories you burn (i.e., the out calories) are burned through your metabolism. These are the calories you burn just to stay alive—breathing, sleeping, and so on. As you age, your metabolism slows down a bit, which you can counter by keeping your muscles strong through strength-building exercises, but unless you’re in the body-building zone, you won’t sway this enough to say, lose 20 pounds in 6 months.
Digesting food accounts for about 10% of the calories you burn. You get a slight boost here if you’re eating mostly whole foods over processed ones since your body has to work harder to digest them and obtain the raw materials it needs (fiber, protein, vitamins, and minerals, for instance). Using white bread as an example, you can think about it this way: When manufacturers remove the components that strip bread of fiber and many vitamins and minerals, it’s as if the food processing plant is doing part of the work of digesting your food. So when you eat processed foods, like white bread, your body only needs to phone it in when it comes to completing the job of digestion. Much of the heavy lifting was already done in the manufacturing plant. That's why you get a bigger calorie-burning boost when you eat whole, unprocessed or minimally processed foods.
Continuing with the "calories out" part of the weight loss equation, it doesn’t take a math whiz to see what we’re left with here: 10% of calories can be burned through exercise. (Some estimates say up to 30%, though I think it’s better to err on the side of caution here, especially for typical exercisers who aren’t training for a marathon or spending hours each day getting sweaty.) A healthy lifestyle program should always include exercise, but you can't out-exercise your diet, so you also need to pay attention to your eating habits.
The hunger effect
Anyone who’s ever taken a spin class can probably tell you that sustained, intense exercise makes you hungrier. Studies back this up, and especially among women. One study that measured the impact of hunger and subsequent food intake after a high intensity exercise session found that women not only reported being hungrier, they ate more—enough to wipe out the calorie-burning effects of a sweaty exercise session. This has been reported in other studies as has the variation among men and women. (The effect is more pronounced among women than men, though there’s variability among both genders.)
As I’ve said, exercise is great for your heart, lungs, muscles, brain, digestion, and more. It’s really good for you! But for weight loss, the results are ‘meh.
The calorie burning myth
Sure, you burn calories when you work out, but it’s often less than you think (or than what your Apple watch or Fitbit reports). It turns out, these devices have a high potential for overestimating what you actually burn. A 2017 Stanford University School of Medicine study found that on average, they're off by 27%, so if you think you burned 700 calories on your last run, it may have been closer to 500 calories. (Heart rate measurements tend to be more accurate, according to researchers.)
Your treadmill is inaccurate, too. And so is your bike. These devices have no way of knowing your fitness level, whether you’re leaning on the handle bars, etc., and other factors that impact how many calories you’re burning, and their algorithms tend to overstate the amounts.
Now recall how out of breath you were when you first started exercising and compare that to how you felt a few months in. Chances are, you could tolerate a 30-minute run better as the months went by. As you get in better shape, your body becomes more efficient, so you burn fewer calories as a result. This is especially true if you routinely participate in the same exercise. If you love swimming and have spent the last five years swimming laps a few times a week, you’re probably burning fewer calories now that you’re a solid swimmer than when you were a novice, even if the number of laps or time in the pool remains unchanged.
The truth is, it’s easy to out-eat exercise and way harder to out-exercise your eating! Taken another way, 100% of the calories you consume are taken in through food, but only about 10% of them are burned through exercise, and as you can see, you’re probably burning less than you think.
I’ve always loved exercising for the physical and emotional benefits, and I used to enthusiastically run and participate in vigorous bootcamp classes, which I thoroughly enjoyed. After suffering an injury, I had to slow down and revamp my routine. Now I’m devoted to Pilates and walking. I exercise because I love the way it makes my body feel, and I like that I’m strong enough to hoist a suitcase into the overhead compartment of an airplane, despite the limitations of my 5’ 2 ½’’ frame. Exercise energizes me, keeps my brain sharp, and promotes creativity—benefits that are well worth it to me. On top of that, exercise is one of the best age-reversing weapons you have in your arsenal. And while the results are unimpressive for weight loss, exercise has been shown to help you maintain your weight--which for many people, is harder than losing weight. So by no means am I suggesting that you take a pass on exercise. It comes down to this: Should you exercise less? No. But weight loss shouldn’t be the focus or purpose of your activities. If you don’t enjoy killer routines, trade them in for movement that inspires you. As we all know, if you like it, you’ll go back for more, and the best exercise routine (or any healthy habit, for that matter) is the one that’s consistent.
If you want to take charge of your weight or want to learn some ways to take the stress out of healthy eating, let's have a quick chat! Schedule a free call to learn how I can help. And if you want some recipes that will help you eat better, download my FREE recipe booklet and grocery guide: 10 Meals & Snacks you can Make in 10 Minutes or less!