“Fake butter” is the common nickname for margarine and other butter-substitute spreads made from vegetable oils instead of dairy cream. These products are designed to look, taste, and spread like butter, but they’re built from an entirely different set of ingredients. A standard tablespoon of tub margarine contains about 2.2 grams of saturated fat, compared to 7.3 grams in the same amount of real butter.
How Margarine Is Made
Real butter starts with cream from cow’s milk, churned until the fat separates. Margarine takes a completely different path. It begins with liquid vegetable oils, most commonly soybean, corn, sunflower, safflower, or cottonseed oil. Since these oils are naturally liquid at room temperature, manufacturers need to transform them into something solid enough to spread on toast.
For decades, the standard method was partial hydrogenation: pumping hydrogen gas through vegetable oil under high pressure. This process firmed up the oil but created trans fats as a byproduct. Trans fats turned out to be worse for heart health than the saturated fat in butter, which gave margarine a bad reputation that lingered for years. The FDA formally revoked all approved uses of partially hydrogenated oils in food as of December 2023, so this process is now effectively banned in the U.S.
Modern margarine makers use a different technique called interesterification. This rearranges the fat molecules within the oil without changing their chemical structure, so the oil becomes firmer without producing trans fats. The biologically active fats in the original oils stay intact. Some brands also blend liquid oils with small amounts of naturally solid fats like palm or coconut oil to get the right texture.
Beyond the fat base, margarine contains water (it’s technically a water-in-oil emulsion, with the fat phase making up about 80% of standard margarine), plus emulsifiers that keep the water and oil from separating. Salt, coloring, and flavorings round out the ingredient list.
What Gives It a Buttery Taste
The compound most responsible for that familiar butter flavor is diacetyl, a naturally occurring chemical that gives real butter its aroma. Food manufacturers add synthetic diacetyl or closely related compounds to margarine, microwave popcorn, and other products labeled “buttery.” Diacetyl is classified as generally recognized as safe (GRAS) by the FDA for eating, and the safety margin is large: the no-effect level in animal studies is roughly 500 times the estimated daily human intake from food.
The safety concern with diacetyl isn’t about eating it. It’s about breathing it. Workers in popcorn and flavoring factories who inhaled high concentrations of diacetyl vapor developed serious, irreversible lung damage. This led to the condition sometimes called “popcorn lung.” For consumers spreading margarine on bread, inhalation exposure is negligible. Some manufacturers have switched to alternative flavoring compounds as a precaution, though at least one common substitute showed similar lung effects at high concentrations in animal studies.
Nutritional Differences From Real Butter
The biggest gap between butter and margarine is in fat composition. Per tablespoon:
- Saturated fat: Butter has 7.2 to 7.3 grams. Tub margarine has about 2.2 grams, and stick margarine about 3.5 grams.
- Polyunsaturated fat: Tub margarine has about 2.3 grams. Butter has only 0.4 grams. These are the fats (including omega-3 and omega-6 types) generally considered beneficial for heart health.
- Monounsaturated fat: Roughly similar across both, around 2.8 to 3.3 grams per tablespoon.
- Cholesterol: Butter contains dietary cholesterol because it’s an animal product. Margarine made entirely from plant oils contains none.
The American Heart Association recommends soft margarine (tub or liquid varieties) over butter for people trying to lower LDL cholesterol, and advises choosing products labeled “0 g trans fat.” For people who need to actively manage cholesterol, the AHA suggests keeping saturated fat below 6% of total daily calories, which is about 13 grams on a 2,000-calorie diet. Two tablespoons of butter would get you there; the same amount of tub margarine would use up roughly a third of that budget.
How It Performs in the Kitchen
Margarine and butter behave differently when you cook with them, mostly because of their fat content and water levels. Butter has a smoke point of 300 to 350°F, meaning it starts to burn and break down relatively quickly in a hot pan. Margarine handles higher heat, with a smoke point around 410 to 430°F, making it more forgiving for sautéing and roasting.
In baking, the differences matter more. Standard margarine at 80% fat performs similarly to butter in most recipes, but lower-fat spreads (sometimes labeled “light” or “reduced calorie”) contain significantly more water and less fat. These can throw off the texture of cookies, pastries, and cakes. If a spread feels very soft and wet at room temperature, it likely has a lower fat percentage and won’t substitute well for butter in recipes that depend on fat for structure.
Flavor is the other obvious gap. Real butter brings a complex, slightly sweet richness that margarine can approximate but not fully replicate. For spreading on toast or cooking savory dishes where other flavors dominate, many people find margarine perfectly adequate. For buttercream frosting or croissants, the difference is harder to ignore.
A Surprisingly Old Invention
Margarine wasn’t invented as a health food. It was invented because butter was too expensive. In the 1860s, Emperor Napoleon III of France offered a prize to anyone who could create “a suitable substance to replace butter for the navy and less prosperous classes.” A French chemist named Hippolyte Mège-Mouriès won the competition with a concoction made from beef fat, minced animal stomach, and chopped cow’s udder, cooked in alkaline water. He patented it in 1871, and by 1880, cheaper versions were in wide production across Europe. The shift to vegetable oils came later, transforming margarine from a meat-based product into the plant-oil spread we know today.
Types of Butter Substitutes
Not everything sold as a butter alternative is technically margarine. The category has splintered into several distinct products. Standard margarine sticks contain about 80% fat and work as close one-to-one substitutes for butter in cooking. Tub spreads are softer, often with slightly less fat, designed mainly for spreading. “Light” or reduced-calorie spreads drop to about 40% fat, replacing the rest with water.
Butter blends sit in the middle, mixing real butter with vegetable oils to reduce saturated fat while keeping some of butter’s flavor. Plant-based “butter” products marketed to vegans use oils like coconut, avocado, or cashew as their base and skip dairy entirely. Spray-on versions deliver a thin coating of oil with butter flavoring for minimal calories but offer no real substitute in cooking.
If you’re choosing between them, the key numbers to compare on the nutrition label are saturated fat per serving and total fat percentage. Higher total fat (closer to 80%) means better cooking performance. Lower saturated fat means a more favorable fat profile for heart health. Products with zero trans fat are now the norm in the U.S., but checking the label is still worthwhile for imported brands.