A comparison of Weight Watcher's Points Plus Values and SmartPoints

Given that I like to use my own software to calculate points (don't worry WW intellectual property police, I don't actually distribute the formulas — I just calculate it on my home machine), I sat down today to dig into the new Smart Points calculations. It turns out the formula is not yet on Wikipedia (in fact, the old formulas are gone — you have to dig through revision history to find them) so I had to sit down with a spreadsheet and reverse engineer the new SmartPoints formula myself.¹

As I did so, I realized the formulas gave me a chance to dig into what's behind the numbers. I'm going to present the numbers in terms of points-per-hundred-calories because that's a nice way to see how Weight Watcher's is going beyond simple calorie counting to try to nudge our behavior in certain directions.

	PPV/100 cal	SmartPoints/100 cal
Carbohydrates	2.7	3.1
Sugar	2.7	6.1
Fat	2.9	3
Saturated Fat	2.9	6.1
Protein	2.3	0.6
Alcohol*	3.1	2.7
Fiber**	-8	0

*Alcohol numbers I've inferred by creating foods w/ a calorie count but no information for other nutrients. That is to say, they could also be taken as a "generic calorie" count -- what WW gives you if you provide it calorie information but no other nutrients. WW doesn't provide an input to enter grams of alcohol into their calculators. I haven't taken the time to check my numbers against actual values for foods with alcohol in the WW database.

**Fiber has no calories of course. I've put here instead the values-per-100 grams. In PPV, grams of fiber offset points from other nutrients. In SmartPoints, as far as I can see fiber has no impact, which makes me thoroughly confused why they still include it in the nutrition calculator...

Digging in a bit more detail

You can't quite trust the above chart as an apples-to-apples comparison, because a point-plus value is not the same as a smart point.

To get a baseline comparison, I thought it would be useful to compare the PPV-per-100-calories for each nutrient to an "average" value², which I calculated to be:

Average SmartPoints/100 calories: 3.7 (or, if you prefer, 27 calories per average SmartPoint)
Average PPV/100 calories: 2.8 (or, if you prefer, 35 calories per average PPV)

I used the "average" points-per-100-calorie value to calculate the "deltas," which is to say, how WW is skewing their numbers to be different from a pure calorie counting system. Below are the differences between the PPV-per-100-calories of a nutrient and the baseline.  Values in this chart that are negative are those foods WW is incentivizing you to eat more of; the positive ones are those that are penalized, and the values give you the size of the penalty or incentive.

	PPV Delta	SmartPoint Delta
Carbohydrates	-4% (0.1)	-16% (-0.6)
Sugar	-4% (0.1)	+65% (+2.4)
Fat	+4% (0.1)	-19% (-0.7)
Saturated Fat	+4% (0.1)	+65% (+2.4)
Protein	-18% (-0.5)	-84% (-3.1)
Alcohol*	-4% (-0.1)	-16% (-0.6)

*Alcohol numbers should be taken with a heavy grain of salt — see above.

So, what does all this mean?

Well, it makes it clear what WW has set out to do: help us eat less sugar and saturated fat, and get us eating more protein. I have no idea how strong the science is supporting those recommendations, but those are the recommendations they're making. My own not-that-informed sense is that there is strong consensus on the recommendations against added sugars and saturated fat. I'm not at all sure how much sense it makes to be eating protein as much as they seem to be pushing. We may all be eating like the Rock soon if we follow this advice.

I think WW does a good job tilting our hands in the right direction, but we have to be careful not to try to game the system too much. In the end, there's probably some truth to the idea that a calorie is a calorie, and I have great faith in my own ability to overeat even when adhering to the healthiest of food choices (I have faith I could get fat eating anything... I just love food too much).

One thing that concerns me is how much stronger the "tilt" is with the new points. If you look at the deltas above, you'll see that with points-plus, you were pretty close to counting calories, with a slight tilt of the formula toward lean proteins and fiber. With the new SmartPoints, the skew is much more dramatic, and that's not something I love.

Two reasons I did WW instead of trying Atkins or South Beach or Paleo or any of the other trendy diets is that (1) I wanted to be able to keep eating real food of all varieties and more importantly (2) I have great faith in my ability to overeat any food category; I don't have one "weak point" when it comes to this stuff; it's all a weak point. For that reason, I'm worried that if WW is relying more on skewing our food choices toward certain categories and away from others, they could end up moving closer to a trendy diet and further from what I've always valued about the program: rather than a particular diet, WW always presented a sensible system to help people figure out how best to manage (and enjoy!) food in their lives. It's not as clear to me they're doing that now.

I know that I found that after my first 40 pounds lost, I could no longer trust myself to eat as much fruit as I wanted and still lose. I never actually counted fruit as "points," but I did have to watch myself with it; obviously the fact that fruit has significant caloric value but no points was catching up to me. I imagine people who binge on lean proteins will run into similar problems with the new system.

On the bright side, if you're one of the lucky human beings who can successfully eat saturated fats and sugar without overeating, you'll probably find the reverse is true: I suspect that there isn't real evidence to back up the enormous penalties WW gives these foods on a caloric basis alone. My suspicion is that the real problem with eating high-sugar high-sat-fat foods is that they tend to make you overeat. I'm not saying I think WW is wrong to penalize these foods — the three pounds I put on last week with a friend's cookie party in the mix is evidence they're right — but still, I'm guessing that the numbers meant to nudge us toward better behavior could also end up misleading if we take them too slavishly.

In the end, I have faith WW is doing their best to present the best calculations to nudge us toward a sustainable relationship with food. That said, it's not a gameable system; it's a program you have to work at. There will be no shortcuts.

Put another way, although a look at the math of the new SmartPoints shows that, eating nothing but protein, I could take in nearly 6,000 calories a day and stay in my budget eating, I'm certain I would gain and gain fast doing that. In the end, though, that kind of absurd hypothetical is besides the point: the real value of points is how they interact with real people making real choices. It's too soon to tell how they work, but I can only hope SmartPoints will work out for the best.

Notes

[1] If you want to get this right, sit down with a spreadsheet and the WW calculator, but here's my initial formula rounded to two significant figures -- all nutrients are in grams:

0.24*Sugar + 0.55*Saturated Fat + 0.27 * (Fat-Sat Fat) + 0.12 * (Carb - Sugar) + 0.024 * Protein + Alcohol * 0.18.

Note, it was pointed out in the comments that someone said you should be able to calculate the points from calories, sat fat, sugar and protein alone. Indeed, you can get very close. The following formula is, in my tests, slightly less accurate but perfectly serviceable:

(0.0305 * calories) - (0.098*protein) + (0.12*sugar)+(0.275*sat fat)

[2] If you're curious how I calculated an "average" calorie, here's what I did. At first I thought I'd just average out the points-per-100cal values, but that's not really fair since you shouldn't eat equal amounts of all those nutrients. So I looked up recommended dietary intake at the Mayo Clinic and used those recommendations to put together these numbers:

	Sugar Val	Sat Fat Val	Non-Sat-Fat Val	Non-Sugar Carb	Protein	Fiber
Recommended calories	100	171	378	1288	448	31
Recommended Grams	25	19	42	322	112	31

Of course that's a full man's diet -- far less than someone trying to lose weight eats -- but nonetheless it still gives me the proportions I needed to calculate out a weighted average number of points-per-100 calories. Another important note is that to do this rigorously, I would have had to try to take into account the weight of 0-points foods — all those calories from fruits and carrots and squash we're not counting here. There wasn't a simple way for me to go from the Mayo Clinic recommendations to calculating how many calories we all should be taking in in "zero points" ways each day, so I didn't bother trying.