Flaxseed oil is perhaps best known as an excellent source of vegetarian-friendly omega-3 fatty acids -- the healthy fats linked to a lower risk of cardiovascular disease. But it might have weight loss benefits, too. Some very preliminary evidence suggests that flaxseed oil -- when substituted for other dietary fats -- might help you lose weight and might offer special health benefits for those who need to lose a few pounds. Like any oil, though, flaxseed oil is high in calories. And with the oil, you'll miss out on the beneficial dietary fiber found in flaxseeds.
Potential Benefits for Weight Loss
Some preliminary animal studies have found that flaxseed oil might help with weight control. One animal study, published in Cytokine in 2012, found that flaxseed oil helped reduce fat cell size in obese rats. The oil also reduced pro-inflammatory compounds in the rats' fat tissue -- an important factor for weight loss, since inflammatory compounds in belly fat increase your risk of chronic disease. One dietary study conducted on people in developing countries -- published in the Journal of the American College of Nutrition in 2010 -- notes that eating diets higher in omega-3 fatty acids and monounsaturated fats, such as the type found in avocados, might help fight obesity.
However, it's too early to say whether adding flaxseed oil to your diet will make you lose weight. The results from animal studies aren't always reflective of how something works in people, and the large population study in developing countries didn't look at whether a simple change -- such as eating flaxseed oil -- makes a difference in weight loss.
Other Weight-Related Benefits of Flaxseed Oil
While it's not clear if flaxseed oil makes you burn more fat, preliminary research indicates it might offer health benefits if you're overweight or obese. Being overweight ups your risk of insulin resistance -- a medical condition that occurs when your body can't respond to insulin properly. Without a normal insulin response, you can't adequately control your blood sugar levels, and insulin resistance can progress to diabetes. One animal study, published in Immunological Investigations in 2015, found that eating flaxseed oil may relieve symptoms of insulin resistance to some degree.
Obesity can also affect the way your cells process fats, a concentrated source of energy for your tissues, including your muscles. One animal study, from a 2015 issue of Biomedical and Environmental Sciences, found that flaxseed oil helped improve fat metabolism in obese mother mice, as well as in their newborns. Further study is needed to see if the same response occurs in humans.
Eating Flaxseed Oil for Weight Loss
Although early research hints that flaxseed oil might help with weight loss or may boost your health if you're overweight, you'll need to watch your portion size. A tablespoon of flaxseed oil has 124 calories. If you eyeball your portion size and end up eating more than a tablespoon, those extra calories can add up quickly, which can get in the way of your weight loss. Always use a measuring spoon to ensure the right serving size.
Flaxseed oil is best served cold to keep its healthy omega-3 fatty acids intact. Use it as a base for salad dressings and sauces -- combine it with lemon juice, garlic, basil and shallot for a flavor-packed dressing or with balsamic vinegar and rosemary for a healthy sauce that works well as a topping for lean beef such as grilled flank steak. You can also blend a teaspoonful or two of flaxseed oil into your smoothies to add richness and nutritional value -- but make certain you count the calories.
Consider Whole Flaxseed Instead
When you're looking to lose weight, whole flaxseed might be a better option than flaxseed oil. You'll still get the same healthy omega-3 fatty acids found in flaxseed oil, but you'll also get a moderate dose of fiber -- 8 percent of the daily value per tablespoon. Adding fiber to your diet promotes weight loss. In fact, making that one simple change of increasing your fiber intake is enough to help you lose weight, reports a study from the February 2015 issue of the Annals of Internal Medicine. Ground flaxseed is also lower in calories than flaxseed oil -- 37 calories per tablespoon, compared to 124 calories for the oil. That means that ground flaxseed takes up less "space" in your calorie-controlled diet, which may make it easier to cut the calories you need to lose weight.