Monday, March 5, 2012

Doing the Math

Leslie Beck is a registered dietician in Toronto who also writes a regular column entitled "Food For Thought" for the Globe and Mail.

There's nothing "health at every size"y about Ms. Beck. A large proportion of her articles deal with how to lose weight. Yes, she does stress eating healthy foods and does not tout fad diets, but her bottom-line message is that we are all better off losing weight. Weight loss is the holy grail.

I was somewhat intrigued, nevertheless, by one of her columns, "The New Weight-Loss Math", published in the G&M on February 22, in which she explains how the standard weight loss math--so beloved of so many weight-loss warriors--just doesn't work out as advertised:

According to U.S. researches, this ubiquitous weight-loss [NewMe here: in other words, cut 3,500 calories and you will automatically lose 1 pound] rule is overly simple and overly optimistic. And it can lead to unrealistic expectations about how quickly you can achieve a weight-loss goal.

The rule contends that cutting 200 calories a day from your diet would lead to a loss of 20 pounds over the course of a year and the weight loss should keep on going. But in reality that doesn’t happen. Weight loss slows and eventually comes to halt despite the drop in calorie intake.

This past weekend, at the American Association for the Advancement of Science’s annual meeting in Vancouver, an international team of researchers unveiled a new formula to better predict how people will lose weight on a diet.

The 3,500-calorie assumption doesn’t account for how metabolism changes during weight loss.

Your metabolism is the rate at which your body burns calories, and it’s largely determined by how much muscle you have, since muscle burns more calories at rest than body fat. Ultimately, it’s your metabolism that dictates how easily you will lose or gain weight.

As the body slims down, metabolism slows, causing it to burn fewer calories at rest. A smaller body also burns fewer calories during exercise. The net result: a sluggish rate of weight loss that can frustrate dieters and cause them to abandon their plan.

Now health-care professionals and researchers have a tool to more accurately predict a dieter’s expected weight loss over time, based on changes to metabolism. Having a more realistic sense of what to expect can help people stay motivated over the long term.

The new formula and accompanying web-based model were developed by researchers from the U.S. National Institutes of Health, the World Health Organization, Columbia University and Harvard School of Public Health,

The online tool – called the Body Weight Simulator – requires people to input their age, gender, body weight, height, activity level and weight goal (

It then simulates what diet and exercise changes are required to reach the goal weight and what changes are necessary to maintain it over time.

Using this model, the researchers found that people’s bodies adapt slowly to dietary changes.

For example, the average overweight person needs to cut 100 calories from their current intake per day to lose 10 pounds over three years.

Half of the weight will be lost in one year and then you’ll reach a plateau, slowly losing the remainder by three years.

In contrast, for the same calorie reduction, the 3,500-calorie formula predicts you’ll lose 10 pounds in one year – and 30 pounds by three years.

I tried out the weight loss simulator myself and found that, given my inability to do heavy exercise, to lose weight I would have to starve. And to keep the weight off? I would have to starve slightly less. As it stands right now--and without doing a serious analysis of my daily caloric intake--I eat healthy foods in reasonable portions, ask myself if I am hungry before eating those few dried apricots, sometimes eat them anyway and sometimes desist, and am basically holding my weight steady. I really don't think that it is either healthy or feasible for me to feel constantly hungry for the rest of my life.

The only thing that I regret is the inability to do exercise that would help me increase my muscle mass. Worse yet, my orthopedic and thyroid adventures have "helped" me to lose further muscle mass. (Re)building muscle mass, I believe, would be a laudable goal--were it possible for me to do so. Indeed, I often wonder what my weight would be today if I weren't so limited in the physical activity that I can safely do. I suspect that I would weight slightly less, but that my body would never agree to be thin--unless I became anorexic and that is not in the cards.

Ms. Beck's article goes on to stress that you must soldier on, even when your weight loss stalls. She suggests the regular tactics, mainly insisting that you must be ultra-vigilant at all times with respect to every single bite you put in your mouth. It's the regular diet talk: what's considered disordered eating for an anorexic is to be applauded in a dieter.

In the meantime, as for me, I keep walking...


  1. and then there is Keven Hall's paper at

    That throws 3500 into doubt.

  2. This was fantastic! Like you, I have thyroid and mobility issues which prevent me from doing much more exercise than I'm doing now. According to that software, using the default number of calories they *say* I'm already eating, it would take me about 6 years to get into the healthy BMI range. Since I already eat about 600 calories *less* than what they assume I do, I'm sure it would take a heck of a lot longer than that. And that's if I can maintain even the low level of exercise I already do. If I sustain any more injuries or assaults to my joints and can't do even that much, well, I may not live to see a healthy BMI unless I eat around 350 calories a day, the number it gave me if I wanted to lose my weight in just 2 years. Yes, 350 calories per day, NOT 350 less than what I they say I am eating now. I guess it's about time I try to accept the fact that I'll never see a normal BMI in my lifetime - didn't as a kid and now that I'm pushing 60 probably never will.

    1. Amazing that something like this is only now coming out, but I'm glad. Thank you for sharing it. Most people trying to lose weight need a reality check in terms of how fast one can lose, how much one can lose, and how much one can keep off in the long run--and what it will take (in terms of effort/discomfort/insanity) to accomplish certain goals.

      I weighed 130-40 in like 3rd or 4th grade...there's a reason my current goal is 200 pounds and I'm not thinking lower than that for now. I want to get to that weight and then assess my situation. In the meantime, I will cherish my ability to do strength training.

      I'm sorry you aren't able to engage in the exercise you desire, but it sure sounds like you eat intelligently. That is worth a lot.

  3. I'm glad to see that 3500 Cal deficit to lose a pound debunked, but still think it's too simple. Obviously, work is completely dependent on mass, so if you're lighter, it uses less energy to move yourself around. While I think calories in/out, or eat less/move more, if you prefer, is very relevant, in my opinion, it's hormones that really decide this stuff, and they're not so good at math. I've been wondering about my own weight loss, definitely not linear, often unexplainable, seemingly irrational. If only it was as easy as most who haven't done it, especially those who don't need to, seem to think it is

  4. Perhaps you should send her my card ; )

  5. Yeah, that magical 3500 calorie stuff is like magical thinking, in my personal experience. It no doubt provokes a lot of disappointment and self-reproach for many people. :(

    I'm compelled to believe (as Julie observes) "it's hormones that really decide this stuff..." because menopause brought a very unexpected gift: the ability to weigh much less (well, so far!) without expending much effort.

    If I live to be 120 (ha!), I will never really have a better explanation than menopausal hormone changes to account for my own weight loss *success* after so many decades of struggle and/or size acceptance and/or utter confusion about my weight/eating.

    Of course, I could gain the weight back. Who can predict the future? Not me. In other words, I don't rule out the possibility that the typical regain experience can happen to me (why NOT to me?), and I won't be too surprised if *maintaining* becomes odious in the future (thus, pointless).

    So far, months and months go by without much fuss or effort, then *it* gets challenging for a few days (or, very rarely, for a few weeks) for no OBVIOUS reason (that is, the impulse to eat more food returns but I don't know why), and then *it* goes back to being routine (ho-hum) again.

    I do try to be a dispassionate observer when that happens (no moral judgement of self, and no jumping to conclusions about what it all might mean.) I don't know if that attitude matters or not.

    I could take credit, I suppose, for this new-found *ability* but that kind of thinking would feel very disrespectful to myself and to others (because I REALLY tried very hard to lose and/or to keep weight off MANY times--but could not accomplish that task long-term, in spite of my best efforts). Taking credit for it now would feel dishonest. It would feel like a kind of cruel self betrayal, too, if that makes sense.

    I don't seem to be able to MAKE myself do much exercise, other than occasional walks (2-3 per week), and those are for pleasure--not because I they are presumably "healthy". Once in a while (maybe twice a month) I play with the 5-lb dumb bells (hand weights) or I do a few sprints on my recumbent bike. If I'm super bored or *antsy* then I'll sit and pedal (and sometimes I PRETEND I'm being virtuous without actually believing it has anything to do with being *good*). So, in terms of energy expenditure, I do nothing dramatic or intense.

    I'm basically the same (mostly sedentary) person I've always been, who enjoys a few movement-related activities. I don't see that part of my personality changing much at this point in my life.

    I can't speak for anyone else who has lost weight but, to me, it would feel YUCKY (self centered and/or narcissistic) to assume that my own experiences with weight loss can be generalized to other people.

    Life continues to be a weird yet compelling mystery.

    1. Talk about "doing the math"...sorry that was so freaking long! :)

  6. The bwsimulator is good in that it provides a somewhat better estimate of what you can expect to lose given some metabolic slowdowns during weightloss with basic caloric reductions and additions of purely cardio exercise.

    I think it is really limited though by the fact it has no way of taking into account INCREASES in muscle mass with things like bodybuilding, or increased fat loss with high intensity interval training.

    It would also be more useful if there were a greater scope of even just cardio exercises to select from when entering increases in physical activity.

    I love the concept though; just really want to see the effects of those other things I mentioned as well.

    And to get really technical it would be great to be able to estimate the effects of nutrient timing too... eventually.