Butter lovers have cursed, ignored and even enacted laws against it, but they haven't been able to stop the spread. Consumption of margarine has steadily -- and rampantly -- increased ever since it was concocted by French pharmacist Hippolyte Me`ge for butter-short troops during the Napoleonic Wars.

These days, descendants of Me`ge's invention fill tubs and sticks and squeeze bottles, jamming supermarket refrigerator cases. In 1987, Americans spent close to $1.5 billion on margarine products, and there's every indication that the buying trend will remain strong. In fact, much to the continual chagrin of farmers and their cows, we now consume twice as much margarine as butter.

The plenitude has wrought confusion, however. Margarine manufacturers have found a timely niche because of the national fixation over fat and cholesterol. Competition in the margarine marketplace now focuses on a given brand's supposedly healthier choice of oil or its ability to help lower blood cholesterol.

Via label claims and television advertisements, we are led to believe there are distinctions that may mean the difference between a prudent purchase and a poor one. Lever Brothers, for example, distributes a 72-percent vegetable-oil spread under the Promise brand that claims to have "no cholesterol" and is "low in saturated fat." What the label doesn't reflect, however, is that no margarines contain cholesterol, and that all margarines are low in saturated fat.

In fact, most margarine-type products are surprisingly similar. The biggest differences are among categories rather than brands. To bring order from confusion and evaluate those differences, it first helps to know the categories.

The Marketplace

There are essentially seven different margarine-type products commonly available in the Washington area -- three "margarines," two "margarine substitutes" and one with brands that fit into both FDA definitions.

The "margarines," which must be at least 80 percent fat by weight, are:

1) Stick margarines, which are more popular than any other kind of margarine product.

2) Soft margarines in tubs.

3) Liquid margarines in squeeze bottles.

4) Margarine/butter blends such as Land O'Lakes Country Morning Blend. Not all blends have enough fat to fit into this category.

"Margarine substitutes" have less than 80 percent fat by weight. These substitutes may or may not be referred to as "imitation margarine," which means that the product is not nutritionally equivalent to margarine in terms of vitamins, minerals and protein. Margarine substitutes include:

1) Margarine/butter blends such as Blue Bonnet's Better Blend.

2) Vegetable oil spreads, which have less total fat than margarine and have shown tremendous sales gains in recent years.

3) Diet or reduced-calorie margarines, which usually have less total fat and fewer calories than vegetable oil spreads. There has been continuing controversy over whether these products can be called "diet" or "reduced-calorie" since the definition of margarine calls for a fat minimum which cannot be met by a calorie-reduced product. The FDA is in the process of reviewing the situation.

Making Margarine

Most margarines and margarine substitutes are created equal -- or almost equal. Made by emulsifying oil and water, they differ primarily in the proportions of oil to water and the degree to which they are hardened.

Spreads and diet margarines have less fat in them because they have more water. Stick margarine products are obviously hardened more than those in tubs or squeeze bottles.

The hardening of oils is called hydrogenation -- a chemical process that involves adding hydrogen gas to a heated oil. The process transforms a small amount of the polyunsaturated fats in the oil to saturated fats, some to monounsaturated fats and leaves others unchanged.

Practically all margarines and margarine substitutes are manufactured with the same additives. Mono- and diglycerides and lecithin are used to emulsify and stabilize margarine; sodium benzoate, potassium sorbate, citric acid and calcium disodium EDTA are used as preservatives; beta carotene is used to color margarine; and artificial flavors are added. Margarines are also fortified with Vitamin A.

Margarine vs. Butter

Some consumers shun margarine because of the additives, claiming that they would rather eat a teaspoon of butter than a tablespoon of colorized yellow glop. And among serious cooks, there are many who are adamant against giving up the taste of butter. Even among health and nutrition professionals, there are differences in opinion.

Margarine (excluding margarine substitutes) and butter each contains 100 calories per tablespoon and 11 grams of fat. The major difference between all margarine-type products and butter is that butter contains cholesterol -- 31 milligrams per tablespoon -- and margarines contain none. The only exceptions to this are margarine/butter blends, which contain a small amount of cholesterol.

The other difference between margarine-type products and butter is the type of fat. The fat in butter is predominantly saturated (7 grams of it), while the fat in margarine-type products is predominantly monounsaturated or polyunsaturated. Regardless of the type of oil used, stick and tub margarines sold in this area generally contain 2 grams of saturated fat per tablespoon; spreads contain either 1 or 2 grams of saturated fat and diet margarines generally contain 1 gram of saturated fat. Saturated fats have been implicated in raising blood cholesterol levels.

Robin Rifkin, a cooking teacher who used to work for Nathan Pritikin, generally uses oil or no fats when cooking, but if faced with a choice between butter or margarine, she will use a small bit of butter because she prefers the taste.

Michael Jacobson, executive director of the Center for Science in the Public Interest, a consumer group that is often quick to criticize food additives, believes that the additives used to manufacture margarine are safe and that from a fat and cholesterol standpoint, margarine is more healthful than butter.

Janet Tenney, nutritionist for Giant Food, uses margarine in her own cooking, but believes that there are no hard and fast rules. If your diet doesn't include much meat or cheese -- two major sources of saturated fat -- then some butter is acceptable, Tenney believes. The trick, Tenney, emphasized, is to decrease the amount of whatever your use.

Margarine Nutrition

The general advice from nutrition professionals has been to choose a margarine with a ratio of polyunsaturated fats to saturated fats of at least 2:1. The American Heart Association had long emphasized increasing the proportion of polyunsaturated fats in the diet, since they have been shown to lower blood cholesterol levels.

But the AHA, along with other nutrition and health groups, has backed away from the polyunsaturate bandwagon, instead recommending that consumers concentrate on decreasing first the total amount of fat in their diets and then the amount of saturated fat. In this context, the ratio loses some importance.

"People who get hung up with choosing the margarine with the highest P/S ratio are getting hung up on the types of fat, rather than total fat," says Giant's Tenney.

In addition, many margarines already fit into the 2:1 category -- or at least are pretty close. "It's not worth agonizing over a 2:1 or a 1:1 ratio," said Bonnie Liebman, director of nutrition at the Center for Science in the Public Interest.

A 2:1 ratio usually means 4 grams of polyunsaturated fat and 2 grams of saturated fat per tablespoon. A 1:1 ratio usually translates into 2 grams of polyunsaturated fat and 2 grams of saturated fat. The rest of the fats are monounsaturated. There is some evidence that these types of fats may also lower blood cholesterol levels.

Joanne Guthrie, a registered dietitian and research nutritionist at the Lipid Research Clinic at George Washington University, said that instead of "nitpicking" over grams of fat in different kinds of margarine, it might be more advisable to switch to a different category altogether. To cut down on total fat, switch from margarine on vegetables to lemon juice, or just jelly on toast instead of margarine and jelly, Guthrie said.

If one looks at margarine and margarine substitutes from the vantage point of calories, total fat and saturated fat, it emerges that: 1) stick, tub and squeeze margarines and margarine/butter blends are virtually identical; 2) margarine substitutes in tubs and sticks have fewer calories, less total fat and usually less saturated fat than regular margarine; 3) diet margarines have the fewest calories, and least total fat and saturated fat.

A survey of products, per tablespoon, at local Giant and Safeway stores shows:

Stick margarine -- 100 calories, 11 grams fat, 2 grams saturated fat. (Imperial, Fleischmann's, Lucerne, Mazola, Mrs. Filbert's, Parkay, Coldbrook, Land O' Lakes, Blue Bonnet.)

Tub margarine -- 100 calories, 11 grams fat, 2 grams saturated fat. (Parkay, Land O' Lakes, Fleischmann's.)

Squeeze margarine -- 100 calories, 11 grams fat, 2 grams saturated fat. These products are generally higher in polyunsaturated fats than any other type of margarine. (Parkay, Fleischmann's.)

Butter/margarine blend -- 100 calories, 11 grams fat, 3 grams saturated fat (Land O' Lakes Country Morning Blend). 90 calories, 11 grams fat, 2 grams saturated fat (Blue Bonnet Better Blend).

Margarine substitute spreads -- 60 to 90 calories, 6 to 9 grams fat, 1 or 2 grams saturated fat. From lowest to highest: Imperial Light Spread (60 calories, 6 grams fat, 1 gram saturated fat); Parkay Spread (60 calories, 7 grams fat, 1 gram saturated fat); Promise Extra Light, Shedd Spread, Mrs. Filbert's Family Spread (70 calories, 7 grams fat, 1 gram saturated fat); Giant Spread (70 calories, 8 grams total fat, 1 gram saturated fat); Mrs. Filbert's Spread 25, Coldbrook Light Spread (80 calories, 8 grams total fat, no data on saturated fat); I Can't Believe It's Not Butter, Promise (90 calories, 10 grams fat, 2 grams saturated fat).

Margarine substitute sticks -- 80 to 90 calories, 8 to 10 grams fat, 2 grams saturated fat. Giant's Generic Spread (80 calories, 8 grams total fat, no data on saturated fat); Shedd Spread (80 calories, 9 calories fat, 2 grams saturated fat); I Can't Believe It's Not Butter, Promise (90 calories, 10 grams fat, 2 grams saturated fat).

Diet margarine -- 50 calories, 6 grams fat, 1 gram saturated fat (Diet Imperial, Weight Watchers Reduced Calorie, Parkay Reduced Calorie.)

The Price of Oil and Water

The following generalizations can be made concerning the cost of margarines and margarine substitutes:

The most expensive products are likely to be those butter and margarine blends that contain a significant amount of butter (such as Country Morning Blend, which has 40 percent sweet cream butter).

The least expensive products are likely to be margarine substitutes in tubs, which often come in containers big enough to feed a small army.

Margarines that come packaged in two 8-ounce tubs are more expensive per ounce than sticks. Diet margarine -- which has more water than any of the other products -- is more expensive than the large containers of margarine substitutes in tubs but is generally less expensive than real margarine in tubs.

And for those who don't buy margarine at all, remember that butter is more expensive than any of them.

Cooking with Margarine Products

Kraft makes a product in five of the categories of margarines and margarine substitutes. Deborah Kraft-Ramsey, manager of Kraft Kitchens, made the following suggestions for cooking with each:

Stick margarine -- All-purpose product. Can be substituted in equal quantities for butter in baked goods, for saute'ing and so on.

Tub margarine -- Main use is table spread, but can be used for saute'ing and in baked goods. Cookie dough may be softer than when using stick margarine.

Squeeze margarine -- Convenience item for pouring over popcorn, vegetables or on top of bread for grilled cheese sandwiches. Can be used for baking, but doughs may be soft. Cake frostings left at room temperature will get watery.

Margarine substitute spread -- Recommended primarily as a table spread. Can be used for baking, but cakes will have a tougher texture. Consumer panels at Kraft were willing to trade the differences for the reduction in fat and calories. Cooks at Kraft's test kitchen have used less milk or water in baked products made with spreads, but have also had satisfactory results using unadapted recipes.

Diet margarine -- Recommended solely as a spread. Because of their high water content, these margarines may spatter when used for saute'ing. Not recommended for baking.

A Taste Test

Since margarine substitutes are the fastest growing category of margarine-type products, Food Section staffers participated in a blind tasting of 16 products available in local supermarkets. The products included margarine substitute spreads, sticks and three diet margarines.

We also conducted a test to see if tasters could differentiate among butter, margarine/butter blend and margarine. All but one staffer identified the products correctly, yet all agreed that making the distinction was more difficult than anticipated. (It could have been because it was conducted after the spread tasting, when tasters tongues were coated with fat.)

The margarine-substitute tasting was not conducted to find the best product, but merely to see the differences between products. They varied only slightly in appearance -- some more yellow than others. They varied somewhat in texture -- some were dryer than others, some were smoother, but all spread equally well.

As for taste, there were no products that testers unanimously liked or disliked. Interestingly, tasters either liked or disliked the diet margarines whereas they were neutral about the other margarine substitutes, indicating that there is a distinct taste difference between those products and the other margarine substitutes.

What It All Means

Remember that all margarines are fats. Thus, the most important point is to use less of any of them or to cut them out entirely, when possible.

Otherwise, when it comes down to choosing which margarines and/or margarine substitutes to buy, the following conclusions can be drawn:

1) If you are looking for a stick margarine for baking, choose the one that is either the cheapest or whose taste you prefer. There do not appear to be significant nutritional differences between brands.

In most cases, it does not pay to bake with tub margarines, since many of them have the same amount of calories, total fat and saturated fat as stick margarines.

If you are on a fat-restricted diet, the difference in total fat between regular margarine and margarine substitutes (in tubs or sticks) may be worth the difference in taste. Experiment with your recipes: in some baked goods, the taste differences may be less noticeable than others.

2) If you are looking for a product for spreading and are concerned about total fat and calories, choose a diet margarine or one of the lower-calorie margarine substitutes over regular margarine in tubs. If you do not like the taste of diet margarines or margarine substitutes, just buy a regular margarine in a tub and use half the amount. It's the same thing.

3) If you want to wean yourself from butter, start by using one of the margarine/butter blends. They have about half as much saturated fat as butter and one third as much cholesterol.