Why I Don’t Eat Back Exercise Calories (And Why You Shouldn’t Either!)

One of the questions I see all the time in the online health/fitness/weight-loss community is whether or not you should eat back your exercise calories. The general consensus seems to be yes. I say no. I don’t eat back my exercise calories, or even track them at all! Here’s why:

The simple reason is that to calculate my calorie needs, I take my BMR (Basal Metabolic Rate–the number of calories your body would burn everyday if you were lying in a coma), and multiply by an activity level factor, then subtract to create a deficit if I want to lose weight. (I explain how to do this here). I eat that number of calories on a daily basis, whether I exercise that day or not. My general level of exercise is already reflected in my choice of an activity level multiplier, so if I ate back my exercise calories I would be eating them twice!

Of course, the other alternative would be to use your daily calorie needs at sedentary (or some other arbitrary calorie level) as a baseline and add back exercise calories on a daily basis. This seems to be the more commonly accepted approach. However, I find this approach problematic for multiple reasons. Here’s why:

1. Eating back calories is inconvenient for planning ahead and meal timing

So you might go to the gym at night after class, in which case you’ll probably burn 500 calories. Do you eat those calories now or later? If you wait until afterwards, you won’t have enough energy for the gym, so you should probably eat them now, maybe in the form of a delicious grilled salmon salad while you’re out to dinner with your friends. But what if you don’t make it to the gym–you’ll go over your calorie count for the day! So instead you order a dry side salad, and plan to gulp down an unsatisfactory protein bar on the way to the gym if you end up going. Wouldn’t it be so much easier just to know in advance how much you can eat every day?

2. In fact, your calorie needs shouldn’t actually change that much from day to day

The majority of the calories you burn come from just living–breathing, circulating blood, digesting food, as well as the activities you do on a day to day basis. You need these calories every day whether you exercise or not. And if you do exercise on a regular basis, your needs should be fairly consistent too. For example, if you’re training for a marathon, you’ll want to fuel on the days before your runs, not just on the days you run. If you lift weights, the muscle growth and repair process actually happens in the 48 hours afterwards, so your body still needs the fuel on the day after your lifts. Unless your exercise habits are extremely sporadic or a particular day is out of the norm (ie you’re normally sedentary but once a month you’ll go on a 10 mile hike), there’s no reason to deliberately vary your intake beyond what results from natural hunger levels.

3. Tracking exercise calories is difficult, time-consuming, and rarely accurate

You know the calorie burn amount that the elliptical or other cardio machine gives you? It’s wrong. Those machines lie, and the only thing you can say for certain is that the number is WAY too high. So if you’re eating back those calories, you’re automatically going to be eating too much. Non-cardio machines don’t even give you a calorie count to work from. And what about jogging, or biking, or “unofficial” exercise like going on a hike or playing a pick-up soccer game or just a particularly vigorous video game? You could spend your life googling calorie burns and tracking every minute of physical activity, but that would get old fast–and again, your calculations might be wrong. What’s the point of eating back exercise calories if the number isn’t even right?

4. Moreover, it steers you toward the wrong kinds of exercise

Which burns more calories, thirty minutes of lifting weights or thirty minutes on the elliptical? Well you don’t exactly know, but you do know that the elliptical tracks your calories–so that’s what you’re going to do. What’s more, it’s gotta be the second elliptical from the right in the third row at your campus gym, because that’s the one that gives the highest read-out. Obviously this line of thinking is silly, but it’s easily to fall into–especially when the number on the machine directly impacts what you get to eat that day. Most people OVERESTIMATE the number of calories they burn doing cardio, and UNDERESTIMATE the number of calories they burn strength training (Courtney at Barbells and Beakers has a number of great articles about this–here’s one to start out with). In reality, lifting weights burns almost as many calories per minute as cardio at the time, it increases your calorie burn throughout the day, and it raises your metabolism in the long run–yet many people prioritize cardio because they think it burns more calories.

5. It also causes discounts the importance of “unofficial” exercise

Tracking and eating back exercise calories can create the inaccurate mindset that ONLY officially designated and tracked exercise “counts,” and can lead people to discount or ignore non-gym physical activity–like the person who circles around the gym parking lot for 15 minutes looking for a closer parking space. In reality, your day-to-day activities–working an active job, raking leaves or shoveling snow, walking to and from class, cleaning the house, getting your groove on in the club–burn many more calories than you think, but it’s easy to forget about them when you’re only tracking “official calories.” So you skip a night out with friends in order to spend a hour on the treadmill, or complain that you don’t have time to shovel the driveway because you have to do your workout DVD, when in reality a night of dancing or intense shoveling would have burned just as many calories without neglecting your obligations or sacrificing your social life. (To see real data on how lifting, cardio, and day-to-day life affects calorie burn, check out The Calorie Burn Experiment at Foods of April. April’s blog was my number one inspiration for my current lifestyle, and really deserves its own post!)

6. It makes you think you can trade off food for exercise (or vice versa)

You’ve heard it a million times and it’s true: you can’t out-exercise a bad diet. Yes exercise enables you to eat more, but even someone who does hard labor and works out twice a day isn’t going to be burning more than twice their BMR. It takes over two hours of HARD exercise for most people to burn 1000 calories–but less than ten minutes to eat it, and unless you’re Lance Armstrong or Michael Phelps, there is no amount of exercise you can do that will let you eat whatever you want. Especially if you’re basing your calorie burn on the grossly over-exaggerated numbers given by the machine. (This is probably a big reason why starting an exercise routine, particularly a cardio-heavy one, can sometimes cause people to GAIN weight–because they significantly overestimate how much they can eat.) On the flipside, this mindset may lead people who don’t particularly enjoy exercise to think that they can skip it altogether and compensate by eating less, which won’t work either. As a generalization, diet is key for losing weight; exercise (especially weight lifting!) is key for maintaining your weight and becoming thinner, tighter, and more defined; both are essential for getting the body you want and you can’t just substitute one for the other.

7. Finally, tracking and eating back exercise calories can create a psychologically unhealthy relationship with food and exercise

This one is a little tricky. Some people benefit from directly associating exercise with caloric intake because it helps them develop a mindset of “Food is fuel,” which can be a good thing (although it’s problematic if that’s the ONLY purpose you see for food). But if tying calories to exercise fuels the attitude that exercise is punishment for food, or that you have to workout to “earn” your right to eat, that’s not a good thing. You get to eat because you’re a living, breathing human being, not because you spent X number of hours in the gym! This mindset can also lead people to spend hours working out to compensate for binges or what they see as unhealthy eating. This behavior is actually an eating disorder known as exercise bulimia (read more about it here) and it can lead to injuries and fatigue as well as bone, heart, reproductive and other problems down the line. (Not to mention that it likely won’t even work-see point 6!) And if you see exercise as a punishment rather than an enjoyable part of your lifestyle, it’s unlikely that you’ll stick with it and maintain your weight for life.

CONCLUSION

So does this mean you should NEVER eat back your exercise calories? That depends. If tracking and eating exercise calories has proved effective for losing weight and maintaining a healthy mindset, then it’s okay to stick to it–it’s all about figuring out what works for YOU! And if you find yourself consistently hungrier on days that you work out, it might make sense to calorie cycle based on your workout schedule even if you don’t officially track (For example, if you work out every other day and your daily calorie target is 1600, you might decide to eat 1800 calories on the days you work out and 1400 on the days you don’t.) There’s also nothing wrong with eating significantly more or less once in a while on days when your activity level is particularly out of the norm–ie you’re vacationing in a new city and spend a whole weekend exploring on foot, or you get the flu and are stuck in bed for a week. 

But if eating back exercise calories isn’t working for you: if you find difficult, time-consuming, or stressful; if it leaves you constantly hungry or overly full; if you’re not losing weight; if you recognize yourself developing an unhealthy attitude towards food and exercise, then it’s time to try something else. Even if you believe that eating exercise calories does work better for you, it’s still worth calculating your average daily needs based on BMR/activity level (which, again, I explain how to do here) to see how the numbers compare (and chances are that if eating exercise calories is working, than the numbers are fairly close).

Finally, if you’re absolutely set on eating back exercise calories, it might be worth investing in an calorie monitoring system such as BodyBugg or Bodymedia, which you wear on your arm 24/7 accurately track your calorie expenditure so you’ll know exactly how much you’re burning throughout the day. The only caveat is these tend to be pricey–they appear to run $100-200 online plus a $6-10 monthly subscription fee after the first 3-12 months. There may be cheaper alternatives out there, but just make sure you do the research and know what you’re getting (for example, most normal heart rate monitors won’t track calorie expenditure unless you’re working at over 75% of maximum heart rate).

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I hope this was helpful and free to pass it on! And as always, don’t hesitate to send me a message if you have any further questions! 🙂