Debunking 3 Myths About Olive Oil's Effects on Weight Loss in 2021

There are many weight loss trends that involve reducing oil intake, going on oil-free diets, or even choosing “light” oils over normal oils. It’s a common belief that limiting fat consumption results in reduced body weight, specifically body fat, but do these diet trends and myths really promote weight loss, or are they counterintuitive? Let’s take a deeper look, focusing on one of the most popular cooking oils, extra virgin olive oil (EVOO). The three most common myths about EVOOs effects on weight loss are discussed below.

Myth #1: Olive Oil Causes Weight Gain

The Truth: Fats found in extra virgin olive oil (EVOO) are very important nutrients to consume. They get broken down into fatty acids, which help promote satiety and reduced appetite. Extra virgin olive oil (EVOO), in particular, contains mainly monounsaturated fats, which have been shown to be beneficial in promoting weight loss. In their recent study, researchers Shatha Hammand and Peter Jones stated that “[u]nsaturated FA, polyunsaturated FA (PUFA) and monounsaturated FA (MUFA), have been found to suppress appetite as well as increase energy expenditure and fat oxidation rate, therefore, induce favorable effects on regional and total fat mass” (1).

In fact, completely removing oils and fats from the diet can actually cause weight gain. Other food groups (fruits, vegetables, dairy, etc.) on their own don’t have the ability to store as much energy and satisfy as much hunger as fats. In a study conducted by Joseph McClernon et. al, researchers compared groups following an LCKD diet (high fat and low carbohydrate ketogenic diet) and LFD (high carbohydrate and low-fat diet). Results showed that the group following the high-fat diet resulted in higher satiety levels and a smaller food intake. Researchers found that “[b]ecause LCKD diets lead to a reduction in the intake of only one class of food (instead of multiple classes, as in a typical caloric restriction diet), dieters may experience fewer food cravings and greater satiety after meals. Moreover, there is evidence that an LCKD leads to a stabilization of blood glucose levels; this stabilization might reduce the craving for food as well as an improvement in energy levels” (2). Reducing fats and eating a higher amount of carbohydrates was shown to increase hunger, food intake, and weight. The bottom line is that extra virgin olive oil (EVOO) does not cause weight gain. Conversely, cutting out extra virgin olive oil (EVOO) and other fats may actually cause weight gain.

Myth #2: Olive Oil Contains Too Many Calories

The Truth: Extra virgin olive oil (EVOO) is pure fat meaning it’s naturally greater in calories than other nutrients. Though caloric intake is a factor, as discussed above, fats have been proven to actually aid in weight loss. Additionally, the reduction of calories is not always correlated with weight loss. In an experiment conducted by Mary Flynn and Steven Reinert, scientists studied the weight changes of participants in one group following an NCI diet (the National Cancer Institute’s standard reduced-fat diet) and another group following a PBOO diet (a plant-based olive oil diet which consisted of participants consuming three or more tablespoons of olive oil every day). Most participants following the plant-based olive oil diet consumed significantly more calories than the people on the reduced-fat diet. Flynn and Reinert stated that “[d]uring week 8 of the PBOO diet, 11 women reported eating 1500 kcal (range 1510–1855 kcal), and 2 reported eating <1200 kcal. For the NCI diet, 18 women reported eating <1200 kcal during week 8 (range 790–1160 kcal), and 2 reported eating 1500 kcal” (3). Results showed that the people who consumed high amounts of olive oil and more calories lost more weight than the people on the reduced-fat diet. Researchers expressed that “Both the lower-fat diet recommended by the NCI and the PBOO diet produced weight loss, but significantly more women (80%) lost at least 5% of their baseline weight when their first 8 weeks of weight loss diet were on the PBOO diet than when their first diet was the NCI (31%)” (3). Additionally many participants in the study chose to continue following the PBOO diet and either maintained their weight loss or lost additional weight. The bottom line is that incorporating extra virgin olive oil (EVOO) into your diet is more effective for weight loss than reducing it, regardless of its caloric content.

Myth #3: Light Olive Oil Is Better for Weight Loss

The Truth: Light olive oil is essentially the same as EVOO in terms of fat and calorie content. The word “light” in light olive oil is just referring to the lighter color and taste, not the nutritional content. In comparison, EVOO is actually the healthiest type of olive oil as it’s pure and not processed. Light olive oil is made by neutralizing and processing EVOO with other chemicals so that it has a lighter color and taste. In an article by H.B. Rice et. al, the authors stated that “[T]he Extra Virgin Olive Oil is commonly known as Extra Virgin Olive Oil, while the Extra Light Olive Oil is commonly known as Olive Oil. Extra Virgin Olive Oil is the oil obtained from the fruit of the olive tree by physical means under conditions that do not lead to alteration of the oil, and that does not involve treatment other than washing, decantation, centrifugation, and filtration. On the other hand, Olive Oil consists of a blend of Virgin Olive Oil and Refined Olive Oil. Refined Olive Oil is obtained from Virgin Olive Oil by refining methods that do not lead to alteration in the original glyceride structure” (4). When it comes to choosing a type of olive oil to help with weight management, extra virgin olive oil is much more natural and healthy than light olive oil. Additionally, EVOO has been shown to aid in weight loss and promote weight management.

The Bottom Line

EVOO does not cause weight gain, contain too many calories, or have an inferior nutrition quality when compared to light olive oil. All of these claims about EVOO are neither accurate nor backed by science. Rather than following oil-free diets, reducing oil intake, and choosing lighter olive oils, incorporating extra virgin olive oil (EVOO) into your diet is an effective way to aid in weight loss and weight management.

Written by Cameron Kao

Reviewed by Kelly Powers, MA, RDN, a Registered Dietitian Nutritionist who takes a holistic approach to nutrition and health. Kelly is a recipe developer with a food blog highlighting whole foods, simple recipes, and her life in San Francisco. She’s the creator of 52 Weeks, a weekly meal plan program that helps users get back in the kitchen and feed themselves well. Kelly is also a co-founder of Olivaio.