Experts Talk About How Scales Measure Up

We recently heard from one Andrew Teton, who wrote asking for tips on how to select his bathroom scale.

There are so many models, he writes--analog, digital, cheap, pricey--and he doesn’t want to spend hundreds on a more accurate, doctor’s-office-style, balance-beam scale, “but I would like to find consistent results from day to day and hopefully determine smaller increments [such as a half pound] to feel encouraged while dieting!”

Well, Mr. Teton, that is a poser.

First, we called up NIST--you know, the National Institute of Scales and Tape measures--to consult a weighing expert.

(OK, we’ll come clean: NIST really stands for National Institute of Standards and Technology, the government body that ensures all kinds of things--gas at gas stations, vegetables in marts--are measured correctly.)

Turns out that NIST’s entire weights and measures staff was at a weights and measures conference, so we can thank our lucky stars no government measuring emergency came up last week. The program director, Henry Oppermann, called us from the meeting.

NIST, he told us, categorizes scales into four accuracy classes. Class I is the most precise (capable of weighing microgram amounts of precious metals, for instance). Class IIII is the least precise (things like your highway weighing station, where micrograms are less of an issue).

All very interesting, but home bathroom scales don’t fall under the NIST’s regulatory purview.

We also called weight loss researcher John Jakicic of Brown University School of Medicine in Providence, R.I. Presumably he could recommend a good set of scales.

But guess what? While he uses the hospital type for semiannual weigh-ins, he’s perfectly happy with a regular model for weekly weighs as long as it is reasonably sturdy and can be calibrated to zero. Analog or digital? Doesn’t really matter. The model he uses has 2 pounds of slop in it easily; so do most, he says.

Bear in mind, there’s a lot of variability in how much we weigh at different times of the day or month (the latter especially in women). Salty food, fluid we’ve drunk, our clothes, what hormones are coursing through our blood, whether we’ve just sweated through a workout--all affect our weight at one moment. Larger trends are what matter.

Jakicic’s advice: Weigh yourself on the same set of scales, at the same time of day, “and don’t get too hung up on the type of scale.”

Armed to the Teeth to Answer Color Query

The Academy of General Dentistry recently told us that its members would be prepared to answer, among other questions, the following intriguing query:

“Why did my teeth turn green?”

We had no idea teeth could go green, so we called the academy and had a nice chat with Dr. Howard S. Glazer, a dentist in New Jersey and New York. We were hoping we could come up with a whole rainbow’s-worth of colors teeth can turn, but there are some, Glazer says, he’s never seen. Like blue. But here are some colors teeth can be, and why:

* White, of course. This comes from the enamel that covers teeth. Why some teeth are naturally whiter is mostly a mystery, though sometimes yellowness is caused by enamel failing to form properly--for instance, when a kid or a pregnant woman has high fever.

* Yellow. Comes from the substance underlying the enamel, called dentine. As we age, that enamel slowly wears, and our teeth yellow up. Only use soft bristle brushes, Glazer says: If he had his way, the hard bristle kind would be pulled off the market.

* Green. Glazer’s best guess on this one: a lab snafu. Sometimes, in making porcelain, the wrong ratio of chemicals is mixed. Voila: green crowns.

* Orange-brown. Stains from wine, coffee, smoking--even eating huge quantities of iron-containing spinach.

* Gray. From the antibiotic tetracycline and related chemicals. It’s rarely seen these days.

* Pink. Glazer thought this was maybe too gruesome to print, but it’s true: Teeth turn pink when we die.

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Booster Shots runs every Monday. If you have a possible Booster Shots item, write or e-mail Rosie Mestel at LA Times, 202 W. 1st St., Los Angeles, CA 90012, [email protected].