America’s Most Popular Cooking Oil Linked to Obesity in New StudyDec 01, 2025 at 10:18 AM EST By Jasmine Laws, US News Reporter A new study has found that soybean oil contributed to obesity in mice, prompting concern that the United States' most popular cooking oil could be playing a role in the country's obesity problem. The University of California, Riverside study, published in the Journal of Lipid Research in October, investigated how mice metabolized linoleic acid, an omega-6 fatty acid widely present in soybean oil, by feeding them a high-fat diet based on the common cooking oil. While the study was conducted on mice, Frances Sladek, a UCR professor of cell biology and author of the study, told Newsweek that the findings "were translatable to humans as the pathways we found involved in soybean oil-induced obesity are highly conserved between mouse and human." Why It MattersSoybean oil is by far the most widely used cooking oil in the country, with rapeseed oil second and palm oil third, according to data from Statista. Soybean oil is also made up of more than 50 percent linoleic acid, Sladek said. The finding raises notable concern, not only because of the oil's popularity, but also because of America's high obesity rates—one in five children and two in five adults are obese in the U.S., meaning they have a Body Mass Index (BMI) higher than 30. Obesity is known to be associated with higher risks of health problems, including diabetes, heart disease and strokes. The American diet has also been called into question by studies previously, as last year a study found that the majority of Americans ate a diet that promoted inflammation, increasing the risk of diseases such as heart disease, obesity, diabetes, depression and certain cancers. Stock image: A person pours soybean oil into a frying pan. | coffeekai/Getty Images What To KnowThe study specifically examined the effects of molecules called oxylipins on mice. These molecules are what linoleic acid is broken down into in the body, and so the higher the consumption of the acid, the higher the amount of these molecules will be in the body. While other fatty acids also break down into oxylipins, the oxylipins derived from linoleic acid were the ones the authors found contributed to obesity in mice. The finding is not new; the researchers noted this result in a previous study. What they did differently in this study was test the impact of a diet high in soybean oil in a group of male mice genetically engineered to express a different version of a liver regulatory gene, P2-HNF4α. This meant they had different metabolic pathways from the control group, as the genetic change reduced the activity of enzymes that convert linoleic acid into oxylipins. The researchers found that the modified mice had healthier livers and gained less weight than the control group on the same diet, further supporting the idea that oxylipins contribute to obesity. “This may be the first step toward understanding why some people gain weight more easily than others on a diet high in soybean oil,” said Sonia Deol, a UCR biomedical scientist and another author of the study. Although the researchers also note that the genetically modified mice had elevated oxylipins on a low-fat diet without becoming obese, suggesting that other metabolic factors are at play. Sladek said that they found that "it is the levels of the oxylipins present in the liver, not circulating in the blood, that correlate with obesity." However, he said that they aren't yet certain about "exactly how the oxylipins drive obesity." How Much Soybean Oil Do Americans Actually Consume?Consuming a small amount of linoleic acid is actually required for human health and is part of a healthy diet; however, the researchers noted that America has had a "remarkable increase" in its consumption of the oil over the past 50 years. The required amount of linoleic acid for health is around 1 to 2 percent of a person's calorific intake, the study authors noted, as small amounts play an important role in maintaining good health. Most Americans broadly have a much higher intake of linoleic acid at around 15 to 25 percent of their calorific intake, the study authors said. Sladek said that consuming small amounts of soybean oil is "perfectly safe and provides a good source of the essential fatty acid linoleic acid." He said that the problem is that "processed foods are becoming an ever larger part of our diet and many of those foods have soybean oil in them, or they have corn oil, safflower seed oil, sunflower seed oil — all these seed oils are made up of large amounts of linoleic acid, just like soybean oil." "So in general, we are taking in much more of these seed oils, all of which have high levels of linoleic acid, than our body needs," he added. What Does Soybean Oil Do to Your Body?It is not clear from the study how these findings would translate to the human body, and further research is needed to determine the impact of soybean oil on human health. However, the study authors note that the findings suggest the possible link warrants further investigation. Sladek said: "It took 100 years from the first observed link between chewing tobacco and cancer to get warning labels on cigarettes. We hope it won’t take that long for society to recognize the link between excessive soybean oil consumption and negative health effects." He also told Newsweek that in previous research, the team found that the soybean oil could impact the intestines, the microbiome and the hypothalamus. He said that while there is a growing body of evidence indicating that dietary linoleic acid is beneficial for the heart, "we have not looked at the impact of a soybean oil diet on the heart." "Different organs will respond differently to dietary linoleic acid and more research in general needs to be done," Sladek added. Other experts are not convinced of the findings, though. Dr. Dariush Mozaffarian, the director of the Food is Medicine Institute at Tufts University, told Newsweek: "Much of the original research suggesting harms of omega-6 [polyunsaturated fatty acids], like this study, was done in mice or rats." "We’ve since clearly learned that humans are not mice, and that these effects don’t translate to what’s seen in humans," Mozaffarian said. "In mice, for example, high fat diets (from any source) cause obesity, whereas in humans, carbs are the problem." He said that in controlled trials in humans, soybean oil and omega-6 polyunsaturated fatty acids were found to "improve blood cholesterol levels, improve glucose control, and lower risk of heart attacks," while in "observational studies," these oils are "linked to less weight gain and obesity risk." Mozaffarian said that soybean oil is a "healthy oil for cooking," and pointed to studies finding that a tablespoon and a half daily of soybean oil could reduce the risk of coronary heart disease, that the oil does not have pro-inflammatory effects, and that those who consumed 5 grams a day had a lower risk of "all-cause mortality." ARTICLE SOURCE: https://www.newsweek.com/soybean-oil-linked-to-obesity-study-11133940
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comment_13328I have made note of carnivore, fasting and trying to hit protein targets. I have altered the fat content and found pretty much where I need to be.
I have also noted I am amazed by the amounts of food other people can eat in one setting. Once I get past a 3/4"-1" rib eye, I'm full and sometimes can manage to eat the other half of my wife's steak, but that can be a stretch. I have tried to hit protein targets as I am getting more and more into lifting at the gym.
The past few weeks I have been on a stretch of overtime. I am averaging just a tad over 66 hours per week. I have been using some of the time on nights to pursue my Google degree in Carnivore and my YouTube College of Medicine Certificate with a lot of the metabolic things that come along with the carnivore diet, fasting and lifting weights (with an autoimmune disease tossed in as well). I'm not close to graduating from either Google nor Youtube, but I am working on those degrees.
I read a ton on the sugar diet (not that I am interested but more so to read about the effects of sugar). I have read a ton on glucose, glycogen, the liver and the pancreas as well as insulin resistance and insulin sensitivity. Instead of watching other people give their (mostly biased) opinions on studies and medical papers I decided to read theirs and then conduct my own experiments on myself. (Maybe inspired by Nick Norwitz, ??)
My first conclusion is that after going without sugar for 13-14 months the least little bit of sugar triggers hunger signals like I have not had in forever. As noted, I am trying to hit protein targets, and I simply can't eat that amount of meat to get to 200 grams of protein. For weight loss and using fat for energy this is a good thing. For weight/muscle gain I don't think I am fueling up as well as I need. I had some ideas and tried to kill two birds with one stone. I bought some of the pre-mixed protein drinks. I tried one, and then waited a week to try another, and then another after the third week. This container has 2.5 servings per bottle and I drank half of it and then 12 hours later the other half.
Rockin' Protein - Shamrock Farms
It has 20grams of carbohydrates and 11 grams of sugar so I'm getting them at 10 and 6 per serving.
Within an hour of each serving I am as hungry as all get out. It does not feel like an old sugar craving as I didn't really have any of those going to carnivore. But I can remember always feeling a little bit hungry. 5-6-7 20oz Mountain Dews and multiple snack cakes thru the day was providing me with the sugar to make my brain say, "I'm hungry again". I am guessing (hypothesizing if this were truly scientific) that by being off sugar/carbs for so long it only takes a very small amount to take me back to "hungry" all over again. (I have found a similar issues with seed oils. I ate them by the buckets before Carnivore and now the least little bit sends me running to the bathroom).
The sugar and the carbs have been a tradeoff for appetite and getting in extra protein. My weight fluctuates/swings normally and that has continued. Maybe up a pound or two more but swings back down to where I am averaging around 215. (still 90lbs off my start point on carnivore).
I could stand to lose some more weight, maybe 15-20lbs or so, but I am not as concerned with weight loss as of late. Super happy with the 90-95lbs in 14 months. Carnivore is still my way of eating, and as far as food is concerned it is still strict carnivore. Once a week or so I am indulging in a few carbs and a few sugars which triggers some hunger. I get the benefit of the extra protein from the drink but at the same time I can get in one more rib eye due to the hunger it provides. Probably not the best method to trigger hunger, but since I never had cravings, I don't see it being my 'gate-way' drug back to Mountain Dews and Little Debbie Snack cakes. LOL
The return? In the past month I can see a difference in my biceps and triceps. And although the aesthetics is not the goal, it is pretty cool to gain a little muscle at 55. The end goal is to gain muscle to offset the natural muscle loss from aging as well as the effects of the auto-immune disease I am trying to reverse with carnivore. The most impressive part so far is the plates I am adding in the gym. I am a lot stronger at 55 than 35. I am not 25 and just out of the service healthy but I am a lot closer to that than I was 14 months ago. And there has been some strides in the last month with "sugar dosing".
If I were struggling with weight still, I might not see this as a grand idea but since I am good with my weight right now, I don't see the harm of the occasional sugar spike. (This is similar to a four-year carnivore friend at the gym who eats sweet potatoes on Thursday nights before a big lift on Friday. Really similar concepts).
Again, not one of those double-blind studies with a thousand humans as control subjects, just me, and my approach to my own health. Maybe not the best plan, but it is my plan, and for now it is working rather well.
babbling on again.
Scott