As alluded to the previous article, there are different types of fats, and they can vary in length, or the number of carbon atoms they contain, and in the number of double bonds between them. For instance, butyric acid (C4), lauric acid (C12), oleic acid (C18), and arachidonic acid (C20) contain 4, 12, 18, or 20 carbon atoms, respectively. Most naturally occurring fats—both in the diet and in the body—contain 16 – 18 carbon atoms, and they are considered long-chain fatty acids.
Also, fats are classified according to the presence and number of double bonds in their carbon chain:
As mentioned above, both the length and saturation of the fats in the diet affect our cell membranes, and therefore, their fluidity. Shorter-chain fats and unsaturated fats are less stiff and less viscous, making the membranes healthier and more flexible. Essentially, understanding the basic chemistry of dietary fat helps us understand the role fats play in our health.
Note that we’re not going into industrial-produced trans fatty acids (i.e., partially hydrogenated oils). Simply put, these are not beneficial at any level. In fact, they are much like tobacco, and any level of intake increases the risk of negative health outcomes.
The short answer is a resounding NO. By no means, however, is it a “bad” question. And the fact that some people still fear fat makes it a really important one to address. But before we dismiss it, a little history lesson.
Believe it or not, the low-fat ideology has its roots in the early 20th century when women dieted in search of slimmer bodies to look better in more revealing, fashionable clothing of the 1920s. Women’s magazines regularly featured diet columns, diets, and recipes, and counting calories was the preferred approach. Educated dieters knew that fat had more than double the calories as carbs and protein, and low calorie, for all practical purposes, was low fat.
The low-fat ideology continued to spread in the 1940s, 50s, and 60s as observational studies seemed to show a correlation between diets high in fat—particularly saturated fat—and increased risk of heart disease (more on this below).
By the 1960s, the low-fat diet was being touted not just for heart health but as the “best” diet for the whole nation. And by 1980, the low-fat diet transcended to an ideology. The faith-inspiring and widely accepted notion that a low-fat diet was good for all Americans as it was promoted by physicians, the government, the food industry, and the popular health media.
However, according to Virginia Tech professor Ann La Berge, “Many Americans subscribed to the ideology of low fat, even though there was no clear evidence that it prevented heart disease or promoted weight loss. Ironically, in the same decades that the low-fat approach assumed ideological status, Americans in the aggregate were getting fatter, leading to what many called an obesity epidemic.”2
Since 1971, the average fat intake in the United States has decreased from 36.6% to 33.6%.3 this isn’t terribly surprising given the emphasis on low-fat diets, the emphasis placed on weight management, and the portrayal of dietary fat in the media over the last several decades. At the same time, we’ve seen a shocking, sharp rise in the prevalence of overweight and obesity—roughly 3 TIMES, depending on where you look.
It really can’t be put any more simply than said by renowned nutrition researchers Dr. Walter Willett and Dr. Rudy Leibel: “Dietary fat is not a major determinant of body fat.”4
Don’t fear the fat! Got the message, loud and clear. But what about saturated fat, which has been demonized over the years? Isn’t it bad for you? Doesn’t saturated fat cause heart disease? After all, the research of Dr. Ancel Keys and others in the 1940s and 50s showed a strong correlation between diets high in saturated fats and increased risk of heart disease, which spawned the low-fat ideology and the “diet-heart hypothesis.” And remember from the brief biochemistry primer above that longer-chain saturated fats would lead to rigid, less fluid cell membranes, which is undesirable. In other words, the argument makes some sense.
Despite the compelling connections, the diet-heart hypothesis has come under great scrutiny of late and been largely dismissed.5 In other words, it’s now widely accepted that saturated fat is not associated with heart-related issues and other adverse health outcomes.6 But doesn’t saturated fat increase blood levels of cholesterol? Yes. But doesn’t elevated cholesterol increase the risk of heart disease? Well, that’s what the “lipid hypothesis” led us to believe. However, despite what we’ve been brainwashed to believe over the years, it’s not quite that simple.
This theory has been called into question, picked apart, and largely discredited in recent years.7,8
Guess what else? Saturated fat is also more adept than mono- and polyunsaturated fats (which are often classified as “healthy”) at raising HDL cholesterol, which is typically classified as “good” cholesterol. Generally speaking, higher levels of HDL are associated with better heart health outcomes (i.e., lower cardiovascular disease risk).
Also, keep in mind that whole, minimally processed foods that contain saturated fat are also typically packaged with other types of fats (mono- and polyunsaturated), key nutrients (like protein), and essential micronutrients (i.e., vitamins and minerals). In other words, when you eat real food, there’s more to the story than saturated fat.
In addition, under the umbrella of saturated fat, there are several different fats (with different lengths/number of carbon atoms), including butyric (C4), hexanoic (C6), caprylic (C8), capric (C10), lauric (C12), palmitic (C16), and stearic (C18) acids. It is important to recognize that these have different biological activities. For example, the C6 – C10 fats are known as medium-chain triglycerides, which appear to burn easily as energy, convert to ketones, boost metabolism, reduce appetite, and support healthy metabolic function.
Generally speaking, most people don’t need to eat more fat per se. Rather, they need to eat a higher quality of fat-containing foods. In other words, instead of the typical diet that’s rich in convenient, packaged, heavily processed foods, which tend to contain fats in the form of added refined vegetable oils and perhaps even hydrogenated trans fats, eating a diet rich in the whole foods mentioned below would be a tremendous step in the right direction for most people.
Said differently, the amount of fat may not be as important as the sources and types of fat you’re consuming. In other words, choice and quality matter.
According to most health organizations (including the World Health Organization, Institute of Medicine, and USDA), the recommended daily fat intake is in the range of 20 – 35% of total calories. In my experience, many people do well in 30 – 40% range, although some people do better toward the lower end of the spectrum (20% or so) while others prefer a much higher fat intake (≥70%), such as on a ketogenic diet.
In general, fat and carbohydrate consumption occur along a spectrum while protein intake is fairly stable (e.g., 0.75 – 1.0 grams per pound of bodyweight per day). As carbohydrate intake goes up, fat intake goes down, and vice versa, such as with a ketogenic diet.
The 30 – 40% range is consistent with the eating patterns associated with the Mediterranean and hunter-gatherer (i.e., Paleo) lifestyles, which emphasize eating REAL food, including both plant- and animal-based foods. Both the Mediterranean and Paleo ways of eating consistently rank highly for diet quality and health outcomes.9
If you were to walk away with one thing from this entire article, my hope would be that it’s this: The types of foods you eat and your overall dietary pattern are far more important for overall health than how much fat you consume. Also, the types of fats—and again, the types of foods in which they are packaged—are arguably more important than the total amount of fat consumed in the diet.
For instance, even though saturated fat isn’t the devil it’s been made out to be, monounsaturated and polyunsaturated fats have important health benefits in the context of an overall healthy dietary pattern. Having said that, even under the umbrella of polyunsaturated fats, it’s critical to ensure you’re getting a healthy balance of essential omega-6 and omega-3 fats.
All that being said, virtually everyone would be well-advised to focus on replacing less healthy fats (such as refined vegetable oils like soybean, corn, canola, cottonseed, safflower, and sunflower) with healthier fats. In other words, eat less processed junk, and instead, focus on eating more REAL food.
In addition to providing healthy fats, whole, minimally processed foods also come packaged with various key nutrients (such as protein and fiber), vitamins, minerals, phytochemicals (which possess health-boosting antioxidant and anti-inflammatory properties), and other non-nutritive compounds. Here are some of the best plant- and animal-based sources of healthy fats:
Dairy products, which encompasses a wide variety of foods including butter, cheese, milk, and yogurt. Although the evidence is not definitive, recent research suggests that dairy, especially full-fat dairy, is related to less belly fat and better markers of cardio-metabolic health, including blood pressure, cholesterol, triglycerides, and glycemic control. Believe it or not, researchers believe these better health outcomes may actually be brought on, at least in part, by the fat components (e.g., saturated fats, milk fat globule membranes).10 Dairy also contains B vitamins, potassium, iodine, and zinc.
What about oils? Are oils considered one of the good fats you need more of? Good question. Believe it or not, most people would probably be best off reducing the amount of fat they add during cooking. Instead, focus on consuming the majority of fat through the whole foods mentioned above. Having said that, the following would be the best oils to use (for cooking, salad dressings, etc.):
There you have it, the skinny on why you need to eat more fat. There’s obviously a LOT here to digest, so if you have any questions, comments, or feedback, fire away in the comments below. We look forward to hearing from you!