Calories and exercise

joggers.jpg

While catching up on my reading on the flight to Dallas I came across an article in the New York Times written by our old friend Gina Kolata. I read the piece and couldn’t believe it: I guess on occasion Gina has an outbreak of good sense. At least such appears the case with her discussion of calories and exercise.

She starts by describing a scenario I’ve witnessed myself all too often.

The Spinning class at our local gym was winding down. People were wiping off their bikes, gathering their towels and water bottles, and walking out the door when a woman shouted to the instructor, “How many calories did we burn?”

“About 900,” the instructor replied.

My husband and I rolled our eyes. We looked around the room. Most people had hardly broken a sweat. I did a quick calculation in my head.

We were cycling for 45 minutes. Suppose someone was running and that the rule of thumb, 100 calories a mile, was correct.

To burn 900 calories, we would have had to work as hard as someone who ran a five-minute mile for the entire distance of nine miles.

There is more confusion as to what constitutes a calorie spent in exercise than about almost anything else in the world of health. People constantly overestimate the number of calories expended in all kinds of activity. The biggest mistake they make (other than overestimating due to lack of knowledge) is to not subtract the number of calories spent in just sitting around doing nothing.

If I look up the number of calories expended in walking, for example, I find that if I walk for an hour at a moderate pace (4 miles per hour), I will burn off about 420 calories. (Click here for a pretty good calorie calculator.) I can find this figure in any number of published tables showing caloric expenditure as a function of activity. Problem is that these tables all include in the calories expended calculations the number of calories one would expend just sitting on one’s butt looking out the window. In other words of this 420 calories I would expend walking for an hour, I would burn about 100 of them simply snoozing. Which means, of course, that I only burn an additional 320 calories by walking a mile – not the 420 calories listed on the charts. And this extra 320 calories can be replaced easily with a little more than an ounce of nuts, which most people wouldn’t think twice about noshing on. That’s one of the reasons it’s so difficult to lose much weight with exercise – you just don’t burn that many calories. And those calories are easy to replace without even thinking.

Most people who exercise don’t burn as much as one walking at 4 miles per hour, which is a pretty good clip.

Claude Bouchard, an obesity and exercise researcher who directs the Pennington Biomedical Research Center in Baton Rouge, La., found that if, for example, the average number of calories burned with an exercise is 100, individuals will burn anywhere from 70 to 130 calories.

And remember, 100 calories can be replaced by a tablespoon of peanut butter. Or by going a little heavy on the olive oil in dressing your salad. These same people that Dr. Bouchard discusses will assume that they’ve burned 400-500 calories with fairly minimal exercise. Then they go off and chow down and wonder why they don’t lose weight.

Ms. Kolata has observed the same phenomenon:

My husband and I will never forget a mathematician at a meeting we attended when we were graduate students. He proudly announced that he could eat a piece of pie because he had just run a quarter-mile on the track. (At 100 calories a mile, he might have burned 25 calories running. A piece of pie could easily contain 400 calories.)

Dr. Bouchard said he regularly sees people at his gym who boast about fantastic numbers of calories they believe they burned. Usually, he just bites his tongue.

“I don’t want to discourage them,” he said.

Sometimes, though, with people he knows well, he tries to tell them that the counts are way too high, and why.

“They look at me in disbelief,” Dr. Bouchard said.

Don’t fall into this same trap. Exercise because it’s good for you: it builds muscle mass, it makes you stronger, it improves bone density, etc. But eat fewer carbs to lose weight.

As to Ms. Kolata’s outbreak of good sense…maybe it’s just the law of averages catching up with her. In no time she’ll be telling us we’re all overweight because we’re not active enough.

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12 thoughts on “Calories and exercise

  1. Merry Xmas Doc to do too! I am looking forwarding to reading your blog in the new year, along with the better health that reading cultivates. I have a question concerning a diet (the Anti-Estrogenic Diet) by ori hofmekler thats been making headlines lately. I’ve read the book; his basic premise is that certain foods should be either avoided or consumed depending on whether they promote estrogen in one’s body. Excess estrogen, ori suggests, causes, among other thing, body fat accumulation, loss of libido, etc. Essentially, he says to eat mostly cruciferous veg, along with onion, garlic, fish, EFA’s, nuts and seeds, fertile eggs, good butter, cheese, some starchy carbs, but to avoid some low-carb staples like beef and pork. Are you familiar with this book? Do you believe there is much truth here or could it be just another fad? Here is a link to a 5min interview he did recently with a texas television show:

    http://www.youtube.com/watch?v=KXlYdIVJyEU&feature=related

    I’m not familiar with this particular book, but I am familiar with the notion that many foods out there thanks to chemical contamination have endocrine disrupting potential. It is true that organochlorines – the most notorious endocrine disruptors – accumulate in the fat of animals that eat food containing these compounds. When we eat these animals, we increase our intake of these compounds. But if we eat starchy carbs, we run insulin up and disregulate its functioning. So, it’s kind of a case of damned if you do and damned if you don’t. In my opinion, the way to best deal with the situation is to eat organic and/or grass-fed animals. By doing so we can regulate insulin AND keep our intake of endocrine disruptors to a minimum. Within the past year I posted on a method to rid the body of these endocrine disruptors. And I posted on another group of chemicals that cause similar problems.

    Best–

    MRE

  2. I understand the point you are making (and agree completely, it’s always been a pet peeve of mine when the helpful advice in the fitness magazines suggest exercising on the elliptical for 500 calories worth and you’ll lose a pound a week), but I’m confused by your math. You would burn 220 calories an hour snoozing? There are 24 hours in a day, that’s over 5000 calories a day burned if you slept for 24 hours.

    Hi Val–

    I fixed the snafu. Thanks for the heads up. That’s what comes from blogging late at night and not rechecking your work. Leads people do divide by 10 instead of 24.

    Cheers–

    MRE

  3. Apart from over-estimating the caloric burn from exercise, this is a nice example of the more general failure of people to think at the margin — that is, how many EXTRA calories does one burn from the exercise. As we learned (and then forgot) in introductory economics, to make good decisions one must focus on the real costs and benefits at the margin.

    Separate issue #1: “The Protein Power Lifeplan” is a great book. Thanks! (If a new printing or second edition is in the works you may want to fix the little typo on p.71. On the 7th line up from the bottom of the page you have “psychological” where I think you mean “physiological”.)

    Separate issue #2: Somewhere on the blog you mentioned that the issue of salt consumption is widely misunderstood, enough so to justify an entire post on salt. As one member of the peanut gallery, I would love to read that post.

    Thanks for the heads up on the typo. I’ll have to check it out when I get back to where I have a book to look at.

    I plan a post on the benefits of salt sometime this next year.

    Cheers–

    MRE

  4. New York Mick Hola…I read this article in ‘Serth Afreeka’ in 02.

    I defer to to your knowledge about the point about how many cal are burned during exercise…does this have any merit pleasum ?

    Bunkum or any sense…

    Thankee

    Why exercise doesn’t burn many calories
    Go to the health club and climb on a stair stepper or treadmill. Program the machine by plugging in your weight, select your speed or program and begin your workout. As you plod along on the apparatus you are driven along by the ever-increasing number on the screen that indicates the number of calories that you have burned. Eventually you go long enough to burn 300 calories and you are left with a feeling of accomplishment. Now, as you wipe the sweat from your brow and catch your breath, let me ask you a question. Why did the machine ask you to program in your weight? If you answered to calculate how many calories you burn you are right. What you most likely failed to consider is the main reason it needs your weight is to calculate your basal metabolic rate. The average male will maintain his weight on about 3200 calories a day. That is about 140 calories an hour at rest. So the 300 calories burned are not calories burned above your basal metabolic rate, they are calories burned including your basal metabolic rate. So for your time on the treadmill, you burned about 160 calories above your baseline. If you eat just 3 cookies, you have completely undone about an hour’s worth of work. Think about it…if we were so metabolically inefficient as to burn 300 calories at the rate the exercise equipment says you do, would we ever have survived as a species. The calories burned hunting and gathering would have caused us to die of starvation before we could ever have found anything to eat. At that rate of calorie burn, we would barely have enough metabolic economy to survive a trip to the grocery store. Most people have accepted blindly the information displayed on exercise equipment and as such have turned exercise into a form of guilt absolution. Have dessert (600 calories of pie) and feel guilty? Just go to the health club and work on the stepper until 600 calories tick by on the screen. Other than the fact that this simply seems pathetic, it also just doesn’t work.

    Let us assume that you have the determination and time to do such a workout 7 days a week. If we take the 300 calories burned and subtract out your basal metabolic rate of 140 calories, we are left with 160 calories burned. There are 3,500 calories in a pound of fat. If your appetite is not spurned by the exercise (as it commonly is) and you keep a stable calorie intake, it would take you 21.875 days to burn off a pound of fat with the extra activity. This is assuming that no other variables are present. Unfortunately there is a big variable that almost no-one accounts for…muscle loss. In order to exercise long enough to reach the 300 calorie mark on the stepper or treadmill, you have to perform low intensity steady state activity. Steady state activity does not place much demand on the muscles, that is why it can be carried out for so long. Rather than demanding use of a large percentage of your muscle fibers, you are actually using a small percentage of your weakest, slow-twitch fibers over and over. When you perform this type of exercise your body can adapt by actually losing muscle. Since you use such a small percentage of your muscle mass to do the work, additional muscle is perceived as dead weight, useless and burdensome. If a person persisted in 7 day a week steady state training they could easily lose about 5 pounds of muscle tissue. Muscle tissue is the most metabolically expensive tissue we have; it takes between 50 and 100 calories a day just to keep a pound of muscle alive.

    Let’s assume the lower number of 50 calories a day. If you lose 5 pounds of muscle over time as you perform your calorie burning exercise that will result in a loss of 250 calories per day that would be used to keep that muscle alive. The 160 calories you burned would probably now be more like 100 burned because with practice, your running or climbing economy improves and requires less effort (most of the perceived conditioning in steady state activity is actually the exercise getting easier not because of improved cardiovascular condition, but because of improved economy of motion. This is why if you take a runner and have him perform another steady state activity such as cycling he will be gasping for air. Indeed, runners who train on treadmills in the Winter notice a large decrease in perceived condition when they hit the road in the Spring). So now if we do the math we will find that you burned about 100 calories above your baseline per day, but we must subtract out 250 calories due to muscle loss. For all your effort you are now 150 calories in the wrong direction. Furthermore, the stress hormones that result from such overtraining also stimulate fat storage. Anyone who has attempted such a program of weight loss can confirm…you will end up feeling washed out, moody, and (worst of all) fatter. The truth is this: you cannot use physical activity to negate excess caloric intake.
    Muscle: the real key to burning calories
    Remember when you were a teenager and could eat everything in sight and not get fat? Somewhere in your 30’s things changed. Now it seems like just looking at food can make you fat. What happened?

    The main difference for most people is that they have less muscle in adulthood than they had in their late teens and early twenties. As we age there is a natural tendency to lose muscle and we also are less vigorous in our physical activity, which results in further muscle loss. This loss of muscle tissue results in a decreasing metabolic rate. Lose 5 pounds of muscle and your calories burned per 24 hours decreases by about 250 calories. While this may not sound like much, it adds up. If you continue to eat like you did when you were younger, you will gain a pound of fat in about 14 days. Over a 20 week period you will gain 10 pounds.

    The key to getting rid of accumulated body fat is to get back your youthful metabolism by getting back your muscle. You have probably heard people say that “muscle has memory”. Well, this is one popular saying that is actually true. With a proper exercise stimulus that dormant muscle can be reclaimed. When you get back the muscle that requires 250 calories a day to keep alive, what used to be an insidious weight-gain problem will become an insidious weight-loss technique. As you become stronger you will have a natural tendency to partake of more vigorous activities. This situation will allow you to lose weight with less attention paid to calorie counting and food selection. The more reasonable your diet can be, the greater your chance to stick with it. As you ride this spiral of success, you may be able to eat more like you did as a teenager. Putting just 5 pounds of calorie burning muscle on your body can really turn things around for you.

    Proper exercise and discriminant weight loss
    SuperSlow inventor Ken Hutchins was the first person to ever explain the idea of discriminant weight loss to me. He told me to picture the human body as a corporation that is run by a board of directors. He told me to assume that a body operating on a calorie deficit is like a corporation running at a budget deficit. Each of the body tissues could represent a different department within that corporation. He then presented two scenarios. In the first scenario there is a budget deficit and no department has any unusual demands. In this scenario layoffs can occur in all departments. So your body lays off some fat, some muscle, some bone and connective tissue, as well as nervous tissue . Your corporation (or body) becomes a smaller version of its former self. In the second scenario, there is a large demand placed on the muscle department. In this scenario, no layoffs can occur in the muscle department. Indeed, more muscle has to be hired on. This results in a larger layoff in the fat department. We cannot produce cutbacks in the bone or connective tissue department because we need their support because muscle is not helpful unless it is attached to strong bone by strong connective tissue. This means more fat has to be let go. We cannot lay off any nervous tissue, because our new muscle is useless unless it is innervated by new nervous tissue. This means more fat has to be let go. Under this scenario, all weight loss is shunted toward fat loss. In this scenario, your corporation (body) takes on a dramatic shape change. You have added a modest amount of shape-improving muscle and jettisoned a large amount of shape-ruining fat.

    Don’t put that in your mouth
    It should now be evident to you that the easiest way to create the calorie deficit you need to lose bodyfat is to simply avoid putting the extra calories in your mouth in the first place. Even a very modest calorie reduction of 150 calories will result in significant fat loss over time. In the long run, the self-discipline required is much easier to produce than the effort of running on a treadmill for an hour every day (which is a losing proposition anyway). A calorie intake deficit of 500 calories a day is still fairly easy to achieve, and if you have added some muscle to your body the shape change you can produce in 6-12 weeks can be amazing. Initially, you may have to be very compulsive about counting calories, but within a few weeks you will probably learn to manage simply by controlling the portion size of the foods you eat.

    In my opinion it is semi-sort of correct. The mistake he (she) makes is by considering the calories in/calories out as being independent variables, which they are not. As caloric intake goes down, so does energy output. The main reason that teenagers don’t get fat is that they are converting their excess calories into growth, not body fat.

    Cheers–

    MRE

  5. Not to mention, as Gary Taubes points out, that energy-out is not independent of energy-in; so exercise will tend to give your appetite a boost.

    But didn’t you mention in one of your books that exercise also increases the number of mitochondria in formerly sedentary muscles, thus increasing “basal metabolic rate”?

    Happy New Year,

    Rick

    I did mention it somewhere, but don’t ask me what page. Also, fat in the diet stimulates the increase in mitochondrial density.

    Cheers–

    MRE

  6. Here’s what I don’t understand. People who exercise more do seem to lose weight, or at least not gain it. It worked for me (in addition to low carb). I’m guessing the mechanisms are a lot more complex, but can you describe, in a little more detail, what those mechanisms might be?

    Thanks.

    It’s a complex explanation. Switching to a diet that nourishes the cells properly by keeping insulin low and allowing fat to leave the fat cells and be used for energy can increase the body’s energy output. Too many people consider calories in and calories out as independent variables, i.e., if you reduce one or increase one the other stays the same. They are not independent variables;they are dependent variables. When you increase food intake, especially low-carb food intake, you increase energy expenditure as well. You fidget more, you run a little hotter, you end up losing more weight than you would think you would simply by counting the change in calories. Often people going on low-carb diets start exercise programs and pursue them aggressively simply because they feel like they need to be more active. Often people going on low-calorie diets have the opposite experience – they become lethargic.

    This whole idea is one of the main themes of Gary Taubes’ book, so if you haven’t read it, you should.

    Cheers–

    MRE

  7. Dr. Eades,

    Many thanks, as always, for your speedy reply in relation to my (and others’) abovementioned comment/question. I read both articles you linked regarding chemicals in our foods and environment and ways to reduce them, along with the posted comments. Another interesting read. I have one more question not quite about chemicals but something similar, concerning the phytic acid in nuts. I very much enjoy eating nuts. But, recently i’ve heard alot about the side effects that phytic acid can cause, namely preventing one from absorbing nutrients from nuts and seeds, as well as inhbiting absorption of nutrients from other foods consumed. To reduce phytic acid, i understand that one should soak their nuts and seeds in an acid medium (e.g. salt water) for a period of approximately 12-24 hours and then dry in, for example, an oven. But is this all really necessary? Or, can nuts and seeds just be eaten as they are, that is, raw without any pre-preparation?

    You may have covered this previously on your blog or in your books, but unfortunately i do not have my copies of your book on hand with me, as i’m spending time “down in the country” with my family.
    Thanks.

    I’ve never heard this about nuts – about other plant foods, yes, but not about nuts. I eat my nuts roasted because I think they taste better that way and because heating tends to break down and weaken (if not destroy) any anti-nutrients that are present.

    Cheers–

    MRE

  8. Regarding estrogen and many of the low carb staples such as beef, pork, full fat cheeses, dairy, etc — Peter may want to look at Wolfgang Lutz’s book – Life Without Bread. He is in his 80s now and has kept methodical records of his patients’ hormonal reactions to a lowcarb diet. Without fail, his records indicate that estrogen levels drop on a low carb diet and then level off yet reintroduction of ad lidem carbohydrate & sugar eating quickly raises estrogen. Lutz’s records are important because they are of hundreds of patients he has followed through the years — not theories based on the seemingly daily headlines about the latest, greatest “study du jour.” As a female who is certainly concerned about trying to minimize risks of hormone related cancers – I am convinced that carbohydrate restriction is the most important and effective way to normalize estrogen levels. That is why women who have excess estrogen and suffer from PCOS find such relief by restricting carbohydrates. That being said, it’s always best to buy organic, grass-fed meats etc when possible/feasible so I agree with Hofmekler on that point and points regarding minimizing exogenous estrogens whenever possible/feasible. I have problems with some of his other dietary suggestions. Low thyroid function also contributes to excessive estrogen and I can assure you that eating lots of nuts and too many cruciferous veggies may impede a normal person’s thyroid function and definitely impede the function of someone who has hypothyroidism or hashimoto’s hypothyroidism. These conditions are very common in middle-aged+ women. Polyunsaturated fats (found in high amounts in the so-called “healthy” nuts) have a high iodine value and impair the body’s utilization of iodine and impede thyroid function. I think that is the primary reason why many people on low-carb stall when they start eating too many nuts — along with the fact that nuts can quickly add up and become calorie/carb bombs. I also don’t see how Hofmekler’s advice to shun animal fat jives with his advice to eat “good butter” and cheese — both items are chock full of animal fats. Seems a tad contradictory to me.

    Hi Annie–

    Great analysis. A much better one, in fact, than I did. I had forgotten about Lutz’s book – I’ll have to dig it out when I get home and read that part again. While I’m at it, I’ll go back through his magnum opus Dismantling a Myth, which is a medical textbook about low-carb dieting published about 20 years ago.

    Cheers–

    MRE

  9. I second Dr. Eades’ comment, in that i too feel Annie’s post was informantive, yet concise. I’ve read Life Without Bread and it was a great read. Unfortunately i didn’t have it at hand at the time of my posting. Of note, i have heard the notion that nuts, as well as a number of vegetables, can greatly impair thyroid function. If this is indeed the case, then perhaps one’s diet should be mostly made up of animal products, like fleshy foods and dairy products like butter and cheese.

    Dr. Eades, if you do a quick search on the web, including the weston price foundation site, there are many cites making reference to the notion that nuts and seeds should be soaked and dried prior to consumption. With that said though, i may rethink eating too many nuts and seeds in light of what Annie said, not because i gain weight when eating them in large quantities but because of their possilbe impact on one’s thyroid.

  10. My lands! What can I eat? I exist on nuts and cruciferous vegetables. My dr thinks I might have Hashimoto’s so should I cut those out? As a type 1.5 diabetic, I cut out fruit, bread, and root vegetables. I hope no one is going to tell me to avoid animal fats because that’s all I’ve got left!

    Wendy

    Hey Wendy–

    I certainly won’t tell you to avoid animal fats.

    Happy New Year!

    MRE

  11. Annie – do you have some accessible cites for your discussion above? I have been assuming that low carb is best for various female issues, but I’d love to see some actual research.

  12. Amazon’s “Search Inside This Book” feature is great! The quotes below refer to two questions from this comment thread regarding The Protein Power Lifeplan:

    on Page 71:
    “… The two types of eicosanoids working in concert can achieve extremely fine control of various psychological processes. For example, eicosanoids derived from the omega- 3 family of fatty acids act as blood thinners. …”

    on Page 305:
    “Brief high-intensity exercises … that work large muscle groups … coupled with a nutrient-dense, higher-fat diet encourage the muscles to increase the numbers of mitochondria, the tiny “furnaces” or power plants, within the cells, where the body burns fuel for energy. …”

    The term “basal metabolic rate” appears neither in The Protein Power Lifeplan nor in Protein Power.