Butter and margarine may stack up next to each other on grocery store shelves, but they may not stack up as easily for the consumer.

Comparing butter and margarine may seem simple. Butter is a dairy product made from the fat of cows’ milk, and margarine comes from vegetable oils. Both have a composition of 80 percent fat and 20 percent water. But as consumer demands change and experts discover different kinds of fats, the comparison becomes a battle of price, flavor and fat composition.

Margarine is a common choice for typical penny-pinching college students. At Hy-Vee, the average price for butter is $2.50, and margarine rings in at less than $2, as low as 47 cents per pound.

“The difference in price is primarily for the source of fat,” said Earl Hammond, university professor emeritus of food science and human nutrition. “The collection of milk and keeping it safe and sanitary is a significant cost. There is more price competition among margarine brands that tends to drive their prices down.”

The demand for milk fat increases when demand for ice cream increases, which can drive prices even higher, Hammond said.

Although margarine may win the price war, butter comes out ahead in the flavor test.

“Butter has unusual fatty acids called lactones and ketones,” Hammond said. “Lactones are released by heat and give the buttery cookie flavor.”

Hammond said some margarines insert synthetic lactones, but ketones cannot be inserted into margarine, making it impossible to perfectly replicate the butter flavor. He said preference on taste is usually a matter of getting used to it. But consumers notice the flavor difference between butter and margarine.

“I use margarine, but when it comes to preference for taste, I choose butter,” said Patti Stringer, senior in performing arts.

Hammond said the flavor of butter can change with the season, based on the cows’ diet.

“Butter in the summer is more unsaturated,” he said. “It is easier to spread and more yellow.”

So the question becomes about how butter and margarine stack up in the fight on fat.

Margarine contains more unsaturated fats, which are healthier than the cholesterol and saturated fats in butter. The hydrogenation process that converts liquid vegetable oils into solid margarine, however, also results in trans fatty acids, which have been noted to increase “bad” cholesterol and lower “good” cholesterol, Hammond said.

Hammond said the hydrogenation process makes the fatty acid compound more straight and compact, which makes it harder for the body to digest. Some experts look at these trans fatty acids as a bigger culprit of heart disease than saturated fats.

In light of hydrogenation, butter starts to take the lead. But it is not that simple.

“Ethrogenic fats can cause heart plaques,” Hammond said. “Milk fat acid is the most ethrogenic fatty acid we eat.”

The bottom line is that neither butter nor margarine has fats that are good for excessive consumption. That was one motivation for Elizabeth Dahlstrom, senior in nutritional science, to create her own cookbook of heart-healthy recipes.

“I started when my dad had heart surgery a few years ago,” Dahlstrom said. “He had to cut desserts and high-fat foods from his diet, but he loves desserts.”

Dahlstrom said saturated and trans fats traditionally found in butter and margarine can cause hardening of the arteries and heart, increased chances of diabetes, stroke, obesity and less healthy skin and hair. She said that low-fat diets are not necessarily the sure-fire way to health.

“It’s the quality of the fat [that matters], not the quantity of the fat,” Dahlstrom said.

For those still caught in a quandary between butter and margarine, there is hope. Hammond said a new process called interesterification treats fats with a catalyst that results in a range of melting points without hydrogenation. This could remove the risk of trans fatty acids in margarine.

Experts recommend reading labels to determine types of fat and limiting intake of butter and margarine.

“The food industry tries to give consumers what they want, but we’re not always right on what’s healthy,” Hammond said.