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Tuesday, October 01, 2013


I was just looking at my page of scribbles and decided maybe this would actually be useful.

See, I like math. I think it is great and helps with all kinds of things, like whether or not the sale price is actually worth it or how long it will take to save up for something.

Also, a while back I posted about the math of weight loss being a reality check and people were responding all "you're over-thinking it" which... respectfully, no. Actually, I'm not.

See, people helpfully replied that all my math is insane and all you really need to do is "eat less and move more."

Which... yes. But that's overSIMPLIFYING by quite a bit. The questions are: Eat how MUCH less? and move how MUCH more?

If I were currently over eating by 500 calories a day and not exercising, and I "eat less" so I'm now "only" eating an extra 300 calories a day, and "move more" so I'm burning 100 calories a day, what is my deficit?

+500 a day over time: 500x31 days = 15500 extra calories a month / 3500 cal/pound = gaining 4lbs a month.

change to:

+300 eaten, - 100 burned = +200. STILL a plus. +200 x 31 / 3500 = 1.8 pounds gained per month.

Gaining weight more slowly may be better than gaining weight really fast, but it's still not **losing** weight.

CLEARLY, it is mathematically possible to "eat less" and "move more" and NOT LOSE WEIGHT - because it depends 1) where you start from 2) HOW MUCH LESS and 3) HOW MUCH MORE

Hence: MATH, Y'all.

In science, you need evidence to support a claim. So I present evidence:

That's my basal metabolic rate, calculated by SP, for how much I weighed during December of 2012. Plus the average calorie burn for the exercise I did in December, and the average calorie intake for the food I ate in December. If you weren't following me at the time, December was my Perfect Month. I tracked every single bite of every single day, all 31 days including Christmas.

Here's the math:

BMR + exercise = total burn. -2349 + -299 = -2648
Burn plus eaten = deficit
-2648 + 1727 = -921.

So, on average, for December, I maintained a calorie deficit of about 921 calories per day. Since a pound is approx 3500 calories, we can look at this two ways:

1) -921 x 31 days / 3500 = -8.2 pounds in December

2) -921 x 7 days /3500 = -1.8 pounds per week.

I lost 10.2 pounds in December, so don't tell me "Math Doesn't Work!"

I did a little better than the math. It is good for me to consistently maintain a calorie deficit of this size. I can maintain a smaller deficit and lose more slowly, but maintaining a deficit of this size helped to buffer the effects of the higher calorie holiday days.

The part where "your body is not a machine" comes in is, time. I did not consistently lose 0.26 pounds per day (921/3500). I did not lose equally every week. There were times with sodium or hormones or whatever that I plateaued during that. But over the entire month? I was not that far off from what the math said.

"Your body will do what it wants"... well.... Yes and no. On the short term, yes. I have plateaued or gained for no apparent reason. But over, say, three months? No. At that point, there's a reason!

In my experience, calories in/calories out WORKS. It's just a question of how you APPLY it, because it only works over time.

The process is finding the **right combination of eating less and moving more** that
1) you can maintain without going crazy for, LITERALLY, MONTHS at a time, and
2) creates enough of a calorie deficit, but not TOO big. Spark provides recommendations for this for a reason.

An average deficit of -1000/day should be fine, IF the way you create that deficit is do-able for you! SP allows us to set our trackers to lose 2lbs a week, and that's what an average deficit of -1000/day works out to: -2 lbs/ week.

Math: -1000 calories a day x 7 days = -7000 calories/week. / 3500 calories per pound = -2 pounds per week

If it was impossible it wouldn't be an option! Also plenty of Sparkers have done it, if you look at the success stories.

There are 52 weeks in a year. There are Sparkers who have lost 100 pounds in a year. 100/52 = 1.9 pounds per week. It's hard to maintain that kind of perfection for a whole year for most people, but it is neither *mathematically* nor *physiologically* impossible. Assuming a person actually HAS 100lbs to lose (I did), and doesn't have some kind of special medical issue (I don't).

Usually, my issue is not being consistent over long enough time period.

But either way, I know this: I am not special. There is nothing inherently different or weird or magical about my body. I am not immune to the laws of physics. I don't have any particular health problems or medications that prevent me from losing weight. If I maintain an average calorie deficit of -1000 calories a day for two months (averaging out by the week - say a -600 one day, -1200 another day, and so on, not no deficit for a week and then try for a -2000, that's too big a swing) I will lose at least 15 pounds.

If I compare December with months I didn't track every day and didn't lose any weight (like, oh, the past six...). Clearly I was not maintaining a sufficient calorie deficit.

I also have no idea what kind of deficit I had, if any, because: I WASN'T TRACKING.

So the math I mentioned in the previous blog looks like this:

current BMR = -2306
planned workout = 3x a week, 40 min run or hour walk, burns about 500 calories for me. So 500 x 3 = -1500/ week

Calorie range = 1320-1670

I need to find the space in this scenario that gives me a calorie deficit, ON AVERAGE of -900-1000 calories per day. Because I know I can be successful on this sort of deficit.

I calculate based on a week because it's supposed to be an average.

-2306 x 7 = -16142 burned just by existing
plus -1500 burned from exercise
= -17642

a deficit of -1000/day = -7000/week (-1000 x 7.) so the difference between burned and deficit = how much to eat in a week

This is algebra; what I really want to know is, burn minus how many calories eaten = -7000

-17642 - e = -7000 add e to both sides
-17642 = -7000 + e add 17642 to both sides
e = 17642 - 7000

e = 10642 / 7 days per week = an average of 1520 calories per day.

What if I want to eat more than that some days? Testing for a fast day:

1670 (top of range) x 6 (days of week) = 10020
plus 600 calories consumed on the fast day = 10620 over all 7 days


go back to the total burn -17642 plus eaten that week 10620
-17642 + 10620 = -7022 ( divide by 3500 calories per pound)

-7022 / 3500 = -2.006

So to lose 2 pounds per week (-ish) if I am exercising 3x a week burning at least 1500 calories during the week, I either need to eat 1520 calories every day, or I can have one fast day at eat more the other six days. It's just a matter of what I prefer and what makes me happier.

Or I could burn more calories - assuming I have time and energy, I will continue to do so.

Also, if I do not burn 1500 calories but still eat 1520 calories per day, I should expect to lose fewer pounds.

OR, if I am getting my workouts in but overeating above 1520 calories each day, ditto.

But either way, historically when I have NOT "done the math", I have not lost weight. I think it's worthwhile. What's the point of controlling my calorie intake if I'm not controlling it in a way that allows me to lose weight?

All this is just to say, it's really not ALL that complicated. All you need is an average over time. (and you don't have to do it with negative numbers, I'm just being a nerd...)

I'm not going to eat 100 calories less today if I overate by 100 calories yesterday, that would just make me neurotic. I DO need to pay attention to when & why I am overeating and by how much. If I'm consistently overeating at a certain time of day and by a certain amount, maybe my calorie range is not a happy place for me; maybe I need to incorporate more filling foods, or maybe I have an emotional eating issue or maybe all three.

But if I can figure it out and bring the math back in line, I can lose again. I have already lost six of the ten pounds I had gained back.

If you don't know where I'm getting these numbers, scroll up to the top of the page and put your mouse over "MY TRACKERS" in the orange bar; then click "reports". You want "Calorie Differential Over Time." You can choose what weeks or months you want to look at, and set it for days, weeks or months (Days is really not that helpful I personally don't think...). If you mouse over the orange bar on the graph it will show you the number Spark is using for your basal metabolic rate. The gray bar is your average burn from exercise tracked. (you can also add up exercise you PLAN to do if you're calculating this in advance like I am) The line graph/little blue dots are calories eaten. You can mouse over to see the week or month average, depending on what you set the report to.

It is REALLY INTERESTING to try this with both the top and bottom of your calorie range!

Add your exercise number to your BMR (from the orange bar) and then subtract your calories eaten (or top and bottom of your range!). Divide this number by 3500 to get pounds per week.

If I don't like the number I see, I try to figure out how to make the activity number go up, or the eaten number go down. Or change what I expect to see when I step on the scale (choosing to lose more slowly is also a valid choice!!).

This was the eye opener for me, when I found with my very low activity the last few months the ONLY way to lose more than a half pound or so was to eat at the VERY BOTTOM of my calorie range, and I simultaneously discovered that trying to eat at the bottom of my range every day resulted in spectacular disaster.

When I TRACK IT ALL and live by the math, I lose by the math. Maybe not down to the ounce exactly, but I don't sit around plateauing or gaining and wondering why, either.
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Member Comments About This Blog Post
    You are so right about the numbers. It's a harsh truth: but throwing our hands up and saying "I don't like math" simply doesn't produce the desired results. Just 100 extra calories a day generates 10 extra pounds year, every year (again, the math tells us this is so). And 100 extra calories is . . . not very much. One medium apple, say.

    (Gotta say for me, tracking the food matters more than tracking the calories burned: because it takes so great an effort to burn calories in comparison with the lesser effort of not eating to excess in the first place . . . but I still need to exercise for cardio/strength/toning and above all mood!)
    2781 days ago
    Great blog! I'm a numbers person too. Knowing the data is important to me. I didn't have that much to lose compared to many sparkers, but it was a tough 25 lbs. Move more? Give up sugary drinks? I was already an active person who drank only water. I needed data to face reality - yes, I was eating WAY to much.
    2781 days ago
    Great blog. Math is important.
    2783 days ago
    LOL I'm a numbers person too. I feel more confident following up on my numbers. It helps me be patient when hormones get in the way.

    Great job!
    2784 days ago
  • MINEA999
    Wow. That was exhausting.

    Math showoff. Truth be told, I kinda skimmed some of those paragraphs because I tend to go cross-eyed when numbers become involved.

    But I will give you this: I BELIEVE YOU. And you're right that it's about consistency over time.

    Other than that, you go get down with your bad math self.... I'm just going to accept the gist of it all.
    2785 days ago

    Comment edited on: 10/1/2013 9:58:44 PM
    Wow, you do love math! I do too, but I confess I didn't read every word (or should I say number) in your blog haha. But I do completely agree with you!!! The times I lose weight are when I calculate my numbers and do a pretty fair job of hitting them. Meaning, I stay (mostly) within the calorie range I set and I (mostly) burn the number of calories I set. I just have trouble maintaining that for more than a couple months at a time.

    I know I've told you before, but I love your blogs! I just caught up on the last few and they always make my day better.
    2785 days ago
    Hooray for math!!!
    2785 days ago
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