For decades, fat was painted as the dietary villain implicated in everything from heart disease to diabetes to weight gain. But new evidence suggests that when it comes to cardiometabolic health, not all fats are created equal. This means that the fats you choose to include in your diet can either raise or lower your risk of cardiometabolic problems.
Did you know? Cardiometabolic disease syndrome is on the rise, affecting approximately 25% of all adults globally. It has become so prevalent, it’s now recognized by the World Health Organization and the American Society of Endocrinology. (1)
Types of cardiometabolic diseases
Before we talk about the role fat plays in cardiometabolic health, let’s take a closer look at cardiometabolic disease itself. If you’ve never heard of cardiometabolic disease syndrome you’re not alone. It’s a fairly new term. Once known as Syndrome X, it encompasses both cardiovascular and metabolic diseases. (2) But despite the name change, the risk factors that cause cardiometabolic disease syndrome—chronically high blood sugar, high blood pressure, unhealthy cholesterol levels, high triglyceride levels, and excessive belly fat—are the same. (3) Having just one of these risk factors can be a concern, but when they are combined, they set the stage for some severe health problems, including:
- Atrial fibrillation (4)
- Coronary artery disease (4)
- Diabetes (5)
- Heart attack (4)
- Heart failure (6)
- Insulin resistance (7)
- Non-alcoholic fatty liver disease (8)
- Stroke (4)
What is dietary fat and why do we need it?
Despite reports linking dietary fat to these conditions, fat is an essential macronutrient you need for good health. Fat provides your body with the energy it needs to function. (9) It also cushions your internal organs, supports healthy cell growth, produces important hormones, and is critical for the absorption of fat-soluble nutrients like vitamin A, vitamin D, vitamin E, and vitamin K. (10) Even though we need a certain amount of dietary fat for good health, two types of fat are more harmful than helpful, especially for cardiometabolic health.
There are two types of trans fats—natural trans-fatty acids found in meat and dairy and manmade trans fats, listed on nutrition labels as partially hydrogenated fats. These artificial trans fats are considered the most harmful of all fats since they have been shown to significantly raise low-density lipoprotein (LDL), a type of cholesterol linked to cardiovascular disease. (11) They also increase the risk of insulin resistance and type 2 diabetes. (12)
Here are some of the most common foods harboring trans fats:
- Coffee creamer
- Crackers, cookies, cakes, frozen pies, and other baked goods
- Fast food
- Frozen pizza
- Microwave popcorn
- Ready-to-use frostings
- Refrigerated loaves of bread and biscuits
- Snack foods
- Vegetable shortenings and some stick margarine types
Did you know? Trans fat is found in many processed foods. But buyer beware! Even foods that claim to contain zero grams of trans fats may still have up to half a gram of trans fats per serving. Double-check the ingredient list for the following foods to see if they list partially hydrogenated oil.
Saturated fats are fat molecules that don’t have double bonds between their carbon molecules because they are saturated with hydrogen molecules. Saturated fats are typically solid at room temperature. For many years, saturated fat was considered harmful because it raised LDL cholesterol, even though it also raised beneficial high-density lipoprotein (HDL). However, a review of 21 studies in the American Journal of Clinical Nutrition that involved 347,747 participants found no connection between saturated fat and heart disease. (13) While the jury may still be out on the impact saturated fat has on your cardiometabolic health, the American Heart Association recommends consuming just 5 to 6% of your daily calories from saturated fat. (14)
You can find saturated fat in:
- Poultry with skin
Dietary fat and cardiovascular disease
Aside from raising LDL levels, how do these less-than-ideal fats affect your cardiovascular system? Dutch researchers recently reported that trans fats trigger inflammation, which can damage the inside walls of your arteries. They also note that these industrial fats can promote fat storage in the liver (which can lead to fatty liver disease) and change the way the liver synthesizes cholesterol. (15)
One study involving more than 57,000 women published in PLoS found that those with the highest level of a biomarker indicating a diet rich in trans fats had a 57% higher risk of a heart attack. (16) Other findings suggest that while saturated fat may not be the boogie man experts once thought, moderation may still be a smart move. A study in the Annals of Nutrition and Metabolism reported that swapping saturated fats for polyunsaturated fats lowered the risk of a heart attack or stroke by as much as 17%. (17) That’s because plant-based polyunsaturated fats like flaxseed or sunflower seed oil reduce inflammation and improve blood flow in arteries. (18)
Dietary fat and insulin resistance
Although most of the research on dietary fat has focused mainly on heart health, a diet high in unhealthy fats can also cause insulin resistance. It turns out that saturated fat—and to a lesser degree, trans fats—can trigger various types of stress in the body that can damage your cells and keep them from responding properly to insulin. (19)(20)
This insulin resistance can be the launching pad for both type 2 diabetes and non-alcoholic fatty liver disease (NAFLD). As the body becomes less sensitive to insulin, it creates inflammation. This inflammation can then lead to more insulin resistance which causes more inflammation. This vicious cycle causes blood sugar levels to creep higher and higher, eventually resulting in diabetes. (21)
Insulin resistance can also cause excess fat to accumulate in your liver. Recent research points a finger at a diet high in saturated fat as one key lifestyle factor for insulin resistance. According to the study, insulin resistance can also speed up how quickly NAFLD morphs into a more serious liver condition called non-alcoholic steatohepatitis (NASH). (22) A new study in the journal Metabolism suggests that a diet high in trans fats can also accelerate the development of NAFLD. (23)
How to pick the right fats for cardiometabolic health
So what fats should you eat? The healthiest types of fat are monounsaturated and polyunsaturated fats. Studies show these can enhance your cardiometabolic health.
Studies show that a diet high in monounsaturated fats can improve insulin sensitivity and cardiovascular risk factors. When Swedish researchers swapped monounsaturated fat for saturated fat in the diets of 162 people, they found that insulin sensitivity improved nearly 9% and LDL cholesterol levels were lower after just three months. (24) Other studies show that trading in saturated fat for monounsaturated fat reduces both total and LDL cholesterol while raising heart-healthy HDL cholesterol. (25) It also lowers blood sugar and blood pressure. (26)
Good sources of monounsaturated fat include:
- Olive oil
- Pumpkin seeds
- Sunflower seeds
There are two types of polyunsaturated fats—omega 3 fatty acids and omega-6 fatty acids. Omega-3 and omega-6 polyunsaturated fatty acids play important roles in inflammation. In general, omega-3s are anti-inflammatory while omega-6s are pro-inflammatory. (27) Eating too many omega-6s and too few omega-3s is thought to promote inflammation and contribute to cardiometabolic disease. (28) That’s why it’s important to balance these two polyunsaturated fats. According to a study conducted by The Center for Genetics, Nutrition and Health, a nonprofit health organization in Washington D.C., the optimal ratio of omega 6s to omega 3s is one to one. However, most people eating a Western diet today consume a ratio of about 16 to one. (29) While eating a diet rich in both omega-3 and omega-6 fatty acids can benefit cardiometabolic health, current wisdom holds that it’s wise not to overdo your consumption of omega-6s. (30) Here’s where to find healthy sources of both these polyunsaturated fats.
- Chia seeds
- Cod liver oil
- Flax seeds
- Grapeseed oil
- Hemp seeds
- Peanut butter
- Pine nuts
- Safflower oil
- Sunflower seeds
The bottom line
Replacing trans fats and saturated fats with healthier monounsaturated and polyunsaturated fats can help bolster your cardiometabolic health. Start by trading ultra-processed foods and fast food for less processed options rich in these beneficial fats. Bonus? By choosing whole, minimally processed food, you’ll automatically bring your omega-3 and omega-6 ratio into a more cardiometabolic-friendly zone.
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- Grundy SM, Brewer HB Jr., Cleeman JI, et al. (2004). Definition of metabolic syndrome: Report of the National Heart, Lung, and Blood Institutes/American Heart Association conference on scientific issues related to definition. Circulation. 109(3), 433-438.
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