Is butter or olive oil better for gaining weight? A nutritional comparison

November 2, 2025 •

4 min read

According to a study published in the American Journal of Clinical Nutrition, replacing butter with olive oil was associated with less long-term weight gain. This finding challenges the simple notion that all high-calorie fats are equal when asking, 'is butter or olive oil better for gaining weight?'. It highlights the importance of fat quality in addition to calorie count for healthy weight management.

Quick Summary

This article compares butter and olive oil for healthy weight gain, focusing on their fat composition, caloric density, and overall health impacts. It explains why the type of fat matters, analyzes their nutritional profiles, and offers guidance on incorporating them into a diet for weight gain.

Key Points

Fat quality matters: While both are calorie-dense, olive oil offers heart-healthy monounsaturated fats, while butter is high in saturated fat.
Olive oil is the healthier choice: Studies link olive oil consumption to less weight gain compared to butter, indicating that the type of fat is more important than just the calorie count.
Moderation is essential for both: Even healthy fats like olive oil are calorie-dense, so portion control is key to a controlled and healthy weight gain.
Both can increase caloric intake: A consistent caloric surplus is required for weight gain, and both fats can effectively add calories to meals.
Choose EVOO for added benefits: Extra virgin olive oil provides extra antioxidants and anti-inflammatory benefits not found in butter.
Calorie density is high for both: A tablespoon of butter has about 102 calories, while a tablespoon of olive oil has about 120 calories.
Consider the overall diet: Focusing on a balanced diet of lean proteins, healthy carbs, and nutrient-dense fats (like olive oil) is best for long-term health, even when the goal is weight gain.

The Core Question: Calories for Weight Gain

At its most basic, weight gain is a matter of consuming more calories than you burn. Both butter and olive oil are calorie-dense foods, meaning they provide a significant number of calories in a small volume. A tablespoon of either can add over 100 calories to a meal, making both effective tools for increasing total caloric intake. However, simply adding extra calories isn't the whole story. The type of fat consumed has a profound impact on health, and this is where the debate between butter and olive oil for weight gain gets more nuanced.

Understanding Caloric Surplus

For healthy weight gain, which typically focuses on building muscle mass and not just fat, creating a consistent caloric surplus is crucial. This can be achieved by increasing portion sizes and choosing energy-dense, nutritious foods. Fats are the most energy-dense macronutrient, providing 9 calories per gram, compared to 4 calories per gram for protein and carbohydrates. Incorporating healthy fats like olive oil or even moderate amounts of butter can effectively increase calories without needing to consume a large volume of food.

Nutritional Breakdown: Butter vs. Olive Oil

The primary difference between butter and olive oil lies in their fatty acid composition. Butter, an animal-derived fat, is high in saturated fat, while olive oil, a plant-based oil, is rich in monounsaturated fats.

Saturated vs. Unsaturated Fats

Saturated fats, such as those found in butter, have historically been linked to higher levels of 'bad' LDL cholesterol when consumed in excess. While recent research has offered a more complex view on saturated fat and heart disease risk, dietary guidelines still recommend limiting its intake. In the context of weight gain, excessive saturated fat consumption is more likely to be stored as body fat compared to unsaturated fats.

Olive oil's high content of monounsaturated fats, particularly oleic acid, offers significant health benefits. Monounsaturated fats are known to help lower LDL cholesterol levels and raise 'good' HDL cholesterol, promoting cardiovascular health. These fats are also more efficiently used by the body for energy, potentially aiding in better metabolic function compared to saturated fats.

Beyond the Fat Profile

Both fats contain different sets of beneficial nutrients:

Butter contains small amounts of fat-soluble vitamins, including A, D, E, and K. Grass-fed butter may contain conjugated linoleic acid (CLA) and butyrate, compounds with potential health benefits, though the concentration in regular butter is relatively low.
Olive Oil, especially extra virgin olive oil (EVOO), is rich in powerful antioxidants, including polyphenols, and vitamins E and K. These compounds provide strong anti-inflammatory properties, protect against oxidative stress, and contribute to overall health.

How to Use Each for Healthy Weight Gain

When using fats to add calories, the goal should be to prioritize overall nutrition. Since a calorie surplus is required for weight gain, incorporating either fat can work, but the health implications differ. Using heart-healthy fats can ensure you gain weight in a way that supports, rather than harms, your long-term health.

For Olive Oil: Drizzle extra virgin olive oil over salads, steamed vegetables, and soups for a calorie and flavor boost. Use it for low-to-medium heat sautéing and frying. Its healthy fats are efficiently used by the body for energy.
For Butter: Enjoy butter in moderation, perhaps 1-2 tablespoons per day, alongside other healthy fats. Use it to add richness to sauces or baked goods. It's best reserved for lower-heat cooking to prevent burning.

Comparative Analysis: Butter vs. Olive Oil


Feature	Butter (per tbsp)	Olive Oil (per tbsp)
Calories	~102 kcal	~120 kcal
Saturated Fat	~7.3 g	~2.3 g
Monounsaturated Fat	~3.3 g	~9.85 g
Polyunsaturated Fat	~0.43 g	~1.42 g
Cholesterol	~30 mg	0 mg
Antioxidants	Low levels	High levels (especially EVOO)
Heart Health Impact	High saturated fat can raise LDL cholesterol	Rich in heart-healthy monounsaturated fats

The Final Verdict

While both butter and olive oil are viable options for increasing caloric intake for weight gain, olive oil is the superior choice for a healthier approach. Its high content of heart-healthy monounsaturated fats and powerful antioxidants supports overall well-being, contrasting with butter's high saturated fat and cholesterol content, which can pose long-term health risks if consumed excessively. For those focused on gaining weight healthily, substituting butter with olive oil is a strategic move that aligns with better nutritional outcomes. Incorporating a variety of high-calorie, nutrient-dense foods, including healthy fats, is the most effective strategy.

Add healthy fats: Drizzle extra virgin olive oil over soups, salads, and cooked vegetables.
Increase protein intake: Incorporate protein shakes, lean meats, fish, and legumes into your diet.
Choose energy-dense foods: Snack on nuts, nut butters, and dried fruits.
Prioritize whole-grain carbs: Opt for brown rice, quinoa, and whole-wheat bread.
Don't forget healthy carbs: Include healthy, energy-dense options like potatoes and sweet potatoes.
Enjoy full-fat dairy: Whole milk, full-fat yogurt, and cheese can be added in moderation.
Eat frequently: Aim for three meals and three snacks daily to maintain a consistent caloric surplus.

For more information on adding healthy calories to your diet, consult resources from trusted health institutions like The Cleveland Clinic.

Frequently Asked Questions

A tablespoon of olive oil has slightly more calories, with approximately 120 kcal, while a tablespoon of butter contains about 102 kcal.

While saturated fat provides calories for weight gain, consuming it in excess is associated with higher 'bad' LDL cholesterol. Healthier, unsaturated fats from olive oil are preferable for a heart-healthy approach.

Yes. Olive oil is rich in monounsaturated fats that are heart-healthy and aid metabolism. Drizzling it on vegetables, salads, and grains is an effective way to increase your calorie intake with healthy fats.

If you choose to include butter, it should be in moderation. Experts often suggest limiting saturated fat intake, so keeping butter to 1-2 tablespoons per day alongside other healthy fats is a good approach.

Saturated fats like butter are more stable at higher temperatures and have a higher smoke point compared to unclarified butter. Clarified butter (ghee) is often used for high-heat cooking. However, for most weight-gaining applications like drizzling or low-to-medium heat sautéing, olive oil is a healthier option.

Olive oil, with its healthy fats, can induce a feeling of satiety. While this is often helpful for weight loss, it can also help prevent overeating unhealthy foods, ensuring your extra calories come from nutrient-dense sources instead.

Yes, a study found that replacing butter and margarine with olive oil was associated with less long-term weight gain, highlighting that the type of fat matters more for health outcomes than just the total calories.

The key takeaway is that the quality of fat is as important as the quantity. For healthier, long-term weight gain, prioritize nutrient-dense, healthy fats like olive oil, nuts, and avocados, and use butter sparingly.