100,000-149,999 SparkPoints 129,789

New Weight-Loss Math: Body Weight Simulator

Wednesday, February 22, 2012

Here's a link to an article in today's Toronto Globe and Mail about a new on-line tool called the Body Weigh Simulator which helps predict how people lose weight on a diet.


The standard weight-loss diet approach tells us: since there are 3,500 calories in a pound of body fat, to lose 1 pound you have to eat 3500 fewer calories or burn off 3,500 more calories with exercise. That's 500 calories a day for seven days to lose 1 pound a week.

But we know that weight loss doesn't happen consistently. Initial weight loss on a diet does tend to follow that pattern. But then weight loss tends to slow. Or plateau. Even if you keep up the 500 a day calorie "deficit".

And that's because metabolism slows with weight loss so that the body burns fewer calories "at rest".

This new Body Weight Simulator tool is pretty interesting because you input age, gender, body weight, height, activity level, weight goal and your time line for reaching that weight goal: and then the tool simulates what diet and exercise changes will be necessary to reach your goal weight. But even more important, what changes will be necessary to MAINTAIN that goal weight over time.

We know, maintenance is the tough part as metabolism slows.

I had lots of fun playing around with this tool. Here's the link to the Body Weight Simulator:


What do I think? The simulator seems to me to overestimate by quite a significant margin the number of calories I can eat a day while still maintaining my current weight. Spark People also overestimates the number of calories I can actually eat.

However, what this simulator makes absolutely clear . . . is that although losing weight requires significant calorie reduction during the "diet" phase, it also requires permanent calorie reduction during the "maintenance" phase.

If I want to weight less permanently, I have to eat less. Yeah. Permanently.

I'm thinking that eating less permanently is also going to mean I'll need to savour hunger. Permanently. Is that OK with me? Yes it is.

As Steve Siebold told me on day three of fatloser.com, "Fat people give in to cravings, fit people prepare for cravings".

Cravings can't be eliminated. Not if I want to be slim.

But if I cultivate an attitude of mental toughness about cravings, the cravings don't last long. Twenty minutes, tops.

The slimness, on the other hand, lasts: 24/7. And the slimness, increased energy, general feeling of alertness and self-control? No question. It's worth it.
Share This Post With Others
Member Comments About This Blog Post
    I enjoyed reading this- thanks for posting!
    2277 days ago
    VERY interesting. I'll definitely have to try it out!
    2277 days ago
    Wow! That article is great, and makes some great points, things that we learn here on SP and in our daily lives but don't always "click" in our brains. However, the simulator...wow, if I eat calories like that, I won't ever lose an ounce - not that I've been losing, I'm on a lovely plateau that my body is enjoying far too much! Anyway, I love playing with things like this, it makes me question, it makes me think and those are good things for me. Thanks for sharing!
    2278 days ago
    That was really interesting. Mine told me I need to eat, well, about what I'm eating to lose weight slowly -- about 5 lbs. in a month. But then maintenance is pretty high!

    Actually, I believe it because I AM losing some fat without getting too hungry, and because a calorie is not a calorie is not a calorie. I fully believe that if I stick to eating whole foods and not starving myself, I'll end up losing fat and keeping my strength.

    I'm also really enjoying my evening walks on these nearly-balmy February days to give me extra burn and activity without giving my body a pounding. It's so much better than sitting around the house!
    2278 days ago
    Yikes,I found it's pretty close to what my BodyMedia armband tells me I burn and the calorie level I should eat. I HOPE it's not significantly off or I'm screwed! emoticon

    I am not usually hungry but then I'm still 20-25 pounds from my goal. Maybe at that point I'll need to learn to savor hunger!
    2278 days ago
    Seems like most of these tools, including SP's, overestimate. I find I have to go almost 1,000 calories under SP's and have the best results when my carbs are 1/2 as much as SP's.

    2278 days ago
    I tried to get it, but the digital signature had expired...
    2278 days ago
    You are the most focused and strong emoticon person!

    I played with it, but I didn't get a good feeling that it is realistic. I think I know what I should eat, how many calories I can take in, and what I need to do physically after so many years of trying to shed those extra pounds.

    Cravings are the monster here! And cravings beget more cravings. Wish there was any easy way to deal with them, but the only way is to withstand them. That's where the strength comes in.

    emoticon Send me some!
    2278 days ago
  • NANCY-
    I understand all too well about cravings and thank heavens they do pass. There is a big difference between desire and need. Meeting one's "needs" fuels us/
    2278 days ago

    I ran it - and if I add walking for an hour a day, I can eat - gasp - 500 more calories and still lose!!!!!

    Not that I seriously believe it.

    BUT - the summer I spent in Italy, I walked all over, at least an hour or two a day, with more hills than I walk here. I ate pretty much what I wanted, keeping in mind to not stuff myself - but pasta for dinner, gelato almost every afternoon, those delightful little sandwiches for lunch - definitely more than I eat at home.

    And I came home 5 lbs lighter. After 5 weeks of eating like that.

    So I know that if I exercised a whole lot more, I could eat a whole lot more. That's my retirement weight loss plan - walk everywhere, eat more.
    2278 days ago
  • _LINDA
    I wasn't able to open the link :( But I found Spark's range works for me -I do extra exercise to ensure I can enjoy all the things I want to eat. If I do an hour of cardio every day, I can eat up to 1960, which is plenty. When I am on surgical layoffs with no cardio, it dropped down to a max of 1600, which was my dieting range. That is restrictive, but doable. So the bottom line is how hard are you willing to work to eat in a normal calorie range.. It is difficult to do, and especially to keep changing up the exercise so your body doesn't get used to it and burn fewer calories...Yep, maintenance is definately harder then actually losing the weight..
    2278 days ago
    Since this is based on the same average caloric needs stats as all of the other generic tools out there, I am very skeptical of the value of this tool.

    I will stick with my own home-made Google Spreadsheet system, which calculates a running estimate of my average daily burn. It automatically adjusts based on what the scale is doing relative to my intake. If I change my activity level that will automatically be factored in.

    Graph here:

    Explanation of how it works, here:
    2278 days ago

    Comment edited on: 2/23/2012 12:56:50 AM
    Interesting....I tried a few variations....not sure what to make of it. Depending on what method you use, I've had these things says I can have anywhere from 1800-2800 calories a day to lose weight based on my activity level.

    I think the Spark estimator is pretty spot on
    2278 days ago
  • Add Your Comment to the Blog Post

    Log in to post a comment

    Disclaimer: Weight loss results will vary from person to person. No individual result should be seen as a typical result of following the SparkPeople program.