WEIGHT LOSS Archives | Math for Grownups

I am not one to talk about my personal weight loss (or gain, usually), especially since I’ve spent years bouncing between feeling good about my figure and avoiding mirrors at all costs.

Fact is, I’ve tried lots and lots of diets — the South Beach Diet, Body for Life, calorie counting, Weight Watchers. I’ve even tried hypnosis and extreme exercise. But even though I have never felt completely successful in these attempts, I haven’t failed. Each time, I’ve refined my goals and figured out things that I will and won’t do.

With all this in mind, I decided in late December that I was going to give Weight Watchers another try. Two things have happened since I was last actively using the program: the PointsPlus program has been refined just a bit, and I wrote a math book. I have to say that thinking about math so much over the last year has been a great benefit in figuring the PointsPlus values for everything I eat.

(In case you have been living under a rock or don’t know who Jennifer Hudson is, the Weight Watchers program is based on a points system. Each person is allotted a certain number of points per day, based on their weight and gender. Everyone also has 49 extra points to eat throughout the week. Foods have points values based on… well, read on, because that’s kind of what I’m getting to in this post.)

My daily PointsPlus allotment is 26. I use online tools to help me track the points of the foods that I’m eating (and the drinks that I’m drinking). And of course, I have those extra 49 points to spread throughout the week.

So first, my math brain figured out that if I use up all 49 points throughout the week (and believe me, I do!), that translates to 7 points per day. If I only eat an extra 5 points one day, I have an extra 9 points on another day. (The 49 points carry over, but if I don’t eat all 29 points in a day, poof! they’re gone.)

Believe me, I’ve gotten damn good at these little calculations. An extra 2 points is the difference between a light and a regular beer.

But it’s the points values themselves that are so amazing, mathematically speaking. Weight Watchers has done some pretty tricky math to make it easier for us to figure out what to eat. Instead of counting just calories, we’re considering four components of our food: protein, fiber, carbohydrates and fat. These values are run through a formula that outputs a handy-dandy PointsPlus value. (Online tools and special calculators find PointsPlus values for any foods, and common values are listed in a variety of Weight Watchers resources.)

This formula is pretty complex. I’ve seen versions of it online, and apparently it is written in black and white in Weight Watcher’s patent. But I don’t need to have the details to know some pretty simple things:

1. Four of the formula’s variables are the amount of protein, fiber, carbohydrates and fat in the food.

2. The answer is likely rounded, since PointsPlus values are all whole numbers.

That last one is pretty important. It means that 0 points isn’t necessarily 0 points.

You see, almost all veggies and fruits count as 0 points — a big change in the program. This makes perfect sense, because we should all be eating more fruits and veggies, not deciding between a banana and a low-calorie fruit bar that was made in a factory far, far away.

But fruits and veggies have calories and sugars. That means an apple may actually have 0.2 points (or something like that). So while one apple may be 0 points, 7 apples probably aren’t. In other words, this is a case of 0 + 0 ≠ 0.

If you’re among the thousands of folks who joined Weight Watchers this month, count math among the skills that will help you lose weight — whether you’re counting your points or trying to make sense of how it all works!

Are you a Weight Watchers member? How have you used math to help you stay on track? Or if you’ve managed your diet in other ways, how has math helped? Respond in the comments section.

you’ve read a women’s magazine or watched one of Oprah’s weight loss shows, you know a thing or two about how to shed those pounds. Move more, eat less, right?

You probably also know how easily we can be fooled by diet companies and nutrition labels. One of those bags of chips you buy at the gas station between errands? The package may claim 250 calories per serving, but the bag may actually contain 2.5 servings.

It’s that tiny little word — per — that screws us up. It’s so little, you might not even notice it. But it can make a big difference between reaching your weight goal and wearing a muumuu on the beach this summer.

If you think back to your elementary or middle school math classes, you may remember your teacher explaining that per means each. And if you think even harder, you might remember the operation (addition, subtraction, multiplication or division) that is indicated by the word per.

Yep, it’s good old division. Think of it this way:

Charlie has six Star Wars figures, and he’s playing with two friends.
“But I want all of them,” he screams. To which you calmly reply, “I know, but that’s not fair. How can we be fair?”
“They can have none, and I can have all of them,” says Charlie, stubbornly.
This is why we teach kids division, you think.

In that situation, you know without a doubt that dividing the Star Wars figures evenly between Charlie and his two friends is not only fair but easy: Because there are six toys and three friends, each friend gets two figures. In other words, there are two figures per child.

You did that in your head, but the math works out.

6 toys ÷ 3 friends = 2 toys per friend

Now, look more carefully at the above statement. Toys per friend translates to 6 ÷ 3 or 2, right? And that means that per means to divide.

Got it? Good. Now you can apply this any time you see the word per. In fact, this is precisely what I did on Wednesday, when I was figuring out how long it would take me to lose 25 pounds.

Whatever you expect to lose in a week, the math is simple:
total weight lost goal ÷ loss per week = number of weeks
25 pounds ÷ 1 pounds per week = 25 weeks
So if you think you can lose 2 pounds per week, it’ll take you 12.5 weeks to lose 25 pounds:
25 pounds ÷ 2 pounds per week = 12.5 weeks

Remember, I also wanted to convert the number of weeks to months — because that’s how my brain works:

I already figured out that I can probably reach my goal in 25 weeks. To find out how many months that is, I can just divide by 4 (the number of full weeks in a month):
25 weeks ÷ 4 weeks per month = 6.25 months

This works for a variety of calculations you may make when embarking on a plan to reach your fitness and weight loss goals. If your trainer says you should exercise for 5 hours per week, you can divide this in a variety of ways:

5 hours ÷ 5 days = 1 hour per day

5 hours ÷ 4 days = 1.25 hours per day

5 hours ÷ 6 days = 0.83 hours per day (or 50 minutes per day)

And so on.

If you practice this skill, you’ll find yourself doing it all over the place — translating miles per hour to your estimated time of arrival, figuring out how many cheddar cheese goldfish are in a half-serving, calculating the exact number of stickers each of your triplets get from the package, and so on.

So get on with your bad self. Use per to your advantage and don’t let servings trick you into eating more than you wanted to.

When do you use division (and per) to help with your fitness and weight loss goals? Share your thoughts in the comments section.

WEIGHT LOSS

How Many Points Is That? (My weight loss journey)

One Little Word, One Big Clue