He likes to compare apples and oranges. Also Brussels sprouts and liver, Twinkies and cantaloupes, potatoes and pizza.

The result is something called Nutripoints, a systemized technique for assessing how nutritious your food really is. Roy E. Vartabedian, a California "clinical preventive care specialist," first published the method 10 years ago and has been refining it ever since.He will be in Salt Lake City on Thursday, May 7, at the Airport Hilton, where he will speak at 7 p.m. Tickets are $10 at the door. Free advance tickets can be reserved by calling 733-0333.

By Vartabedian's accounting - detailed in his book "Nutripoints: A New Guide to Simple, Healthy Eating" - turnip greens are the perfect food, earning 79 Nutripoints. By contrast, Yoplait banana custard style yogurt gets a minus 1, only two points above a Twinkie.

To come up with his numbers, Vartabedian looked at 3,000 different foods - from raw spinach to Big Macs - assessing them for 26 factors. How many RDAs (Recommended Daily Allowance) of vitamins do they provide? How much sodium? Cholesterol? Calcium? The data came from the U.S. Department of Agriculture and from groups such as the American Cancer Society and American Heart Association.

Vartabedian then fed all the numbers into a computer and came up with a "compromise" number for each food, one that takes into account the food's benefits and its excesses (it may be low in fat, for example, but high in sodium.) Then he divided that number by the number of calories in the food. The final number is the food's nutrients per calorie, says Vartabedian. In other words, the most efficient use of the calories you consume.

"You have to be a walking computer," says Vartabedian, to figure out on your own which foods are better for you than others.

He recommends getting at least 100 Nutripoints a day. An apple will give you only 4.5 points. Pickle relish gives you a minus 6. Raw broccoli is a plus 53.

He recommends dividing up your 100 points this way: 55 points for vegetables, 15 for fruits, 10 for grains, 10 for milk/dairy and 5 for legumes.

It's not a perfect system, Vartabedian admits. It doesn't take into account, for example, phytochemicals - those traces of plant nutrients that scientists have only recently begun to understand - because there is no way yet to identify or quantify them.

And it isn't specific for certain conditions or goals. If you're interested in lowering your cholesterol, for example, you might want to eat oatmeal, which is a soluble fiber - but if you look up oatmeal on Vartabedian's chart you'll find that oatmeal gets only 5.5 points (compared to Whole Wheat Total's 64.5).

In addition to the book, Vartabedian's Nutripoints system now also includes a video tape, audio tape, daily record sheet and wall chart. The good foods are on the front, in color; the bad guys are on the back, in black and white.

But it's the book itself that provides hours of mouth-watering, and appetite-spoiling, reading. Here's a sample: papaya, 20.5; parsley, 54.5; pumpkin seeds, 2.5; Pop-Tarts, (frosted, strawberry) 1.0, pudding (Hunt's Snack Pack, chocolate), minus 4.