First, we feared eating too much fat. Then, the pendulum shifted, and we started to eye carbs as the enemy. But what's the real deal?
Now, a global study published in The Lancet is challenging the notion that one necessarily needs to be worse than the other: Rather, it might be that eating too much or too little of the nutrients is the actual problem.
Researchers from McMaster University in Canada followed more than 135,000 people in 18 countries—from South America to Africa to China—for about seven years. After analyzing survey data about their diet and health, the researchers found that people who ate more than 68 percent of their total calories from carbohydrates were 28 percent more likely to die during the follow up than those who took in a lesser percentage of their calories from carbs.
While the researchers didn’t look into the specific types of carbs these people were eating, it’s safe to assume based on past research that a large chunk of those carbs are refined ones, like white bread and rice, says lead study author Mahshid Dehghan, MS.c., Ph.D., especially when you consider countries with higher levels of poverty.
The nutritional breakdown of carbs is important, since previous studies suggest that foods with a high glycemic index—meaning they spike your blood sugar faster, like refined carbs tend to do—can increase your risk for several chronic diseases, like obesity and diabetes, says Dehghan. So while we don't advise cutting your carbs, we do recommend the majority of them come from complex sources, like whole grains and vegetables.
The 5 Best Foods To Fight Heart Disease:
As for fat? It had the opposite effect. When people ate more fat, their risk of death during that time period decreased. In fact, those who ate roughly 35 percent of their calories from fat were 23 percent less likely to die during follow-up than people who only consumed 11 percent of their calories from fat.
This relationship held true when considering all kinds of fat, including saturated, monounsaturated, and polyunsaturated. But doesn’t fat make you fat? Not necessarily. In fact, eating reduced fat foods can lead to weight gain, some research suggests.
What Should Your Macronutrient Balance Look Like?
“The message of our study is moderation,” says Dehghan.
Think about it: When you go on an extreme kind of diet—say, a super low-fat one—the rest your calories have to come from somewhere, right?
“When you reduce one component of your diet, you replace it with something else,” says Dehghan. “When you reduce your total fat, by default, you replace it with refined carbohydrates.” The result? Loading up on processed foods—like breakfast cereals, soda, and white pasta—can easily lead to weight gain, which spikes your risk for serious health issues, such as heart disease.
The reverse is possible when you go super high-fat and low-carb too, popularized by the ketogenic diet. When you don't eat enough carbs, your energy levels might crash, since they're your body's main source of fuel.
“We are not supporting very low carb or very high fat diets," says Dehghan. “We are saying that reducing your carbs is likely beneficial when [your intake] is already high.”
She adds that the purpose of their study is to present new evidence to add to the ongoing discussion of what a healthy diet should look like. Based on their specific findings, people should aim to eat 50 to 55 percent of their calories from carbs and roughly 35 percent from fat to reduce their risk of premature death, says Dehghan.
The study didn't specifically look at protein, which, along with carbs and fat, is vital in considering your macronutrient breakdown. So we decided to compare the study's recommendations for carbs and fat percentages to what the current Dietary Guidelines for Americans advises—while zeroing in on its recommended protein allowance, too.
The dietary recommendations from the study actually aren't so far off: The U.S. Dietary Guidelines say 45 to 65 percent of your calories should come from carbohydrates, while 20 to 35 percent should come from total fat. You should also get 10 to 35 percent of your calories from protein.
We checked in with Jim White, R.D., owner of Jim White Fitness Studios, to see if we could break all this down. Based on everything we learned, for the average guy looking to stay healthy, what should his macronutrient breakdown really be?
Shoot for 50 percent carbs, 30 percent protein, and 20 percent fat, he recommends, which seems to be a happy medium based on recommendations listed above. Making slight adjustments to your protein, carbs, and fat, won’t make a huge difference in results if you’re keeping your overall calories in check, he says. (Find out how many calories you need here.)
But if you have certain goals—say, you’re looking to build muscle or lose weight—then you may want to include more protein, but 35 percent is the highest White recommends. Then, you can adjust your fat and carbs accordingly. (In need of great recipes that will help you get there? Check out the Metashred Diet from Men's Health.)
Bottom line: No matter your personal macro ratio—which you can find here—pay attention to the nutritional breakdown of the foods you’re eating. And when you go lower in one nutrient, note what you’re replacing those missing calories with. It could make all the difference in your health.
Alisa HrusticDeputy Editor, Prevention
Alisa Hrustic is the deputy editor at Prevention, where she leads the brand’s digital editorial strategy. She’s spent the last five years interviewing top medical experts, interpreting peer-reviewed studies, and reporting on health, nutrition, weight loss, and fitness trends for national brands like Women’s Health and Men’s Health. She spends most of her days diving into the latest wellness trends, writing and editing stories about health conditions, testing skincare products, and trying to understand the next greatest internet obsession.
By Franziska Spritzler — Medically reviewed by Jillian Kubala, MS, RD, Nutrition — Updated on October 16, 2020
Fat is an important part of your diet, but figuring out how much to eat can be confusing.
Over the last 50 years, many people have moved from a moderate fat to a low fat diet, based on recommendations from health organizations.
However, the 2020-2025 Dietary Guidelines for Americans no longer specifies an upper limit for how much total fat you should consume.
This article takes a detailed look at different types of fat and provides suggestions for how much to eat per day.
Along with protein and carbs, fat is one of the three macronutrients in your diet.
You consume fat in the form of triglycerides. A triglyceride molecule consists of three fatty acids attached to a glycerol backbone. The fatty acids contain chains of carbons and hydrogens.
One way to classify fats is by the length of their carbon chains:
Most of the fats you eat are long-chain fatty acids. Short-chain fatty acids are mainly produced when bacteria ferment soluble fiber in your colon, although milk fat also contains small amounts.
Long-chain and very long-chain fats are absorbed into the bloodstream and released into the body’s cells as needed. However, the liver takes up short-chain and medium-chain fats directly and stores them as energy.
Fat performs a number of functions and provides several health benefits:
The fat stored inside your body helps:
Fatty acids are grouped according to the number of double bonds between carbons in their structures.
Monounsaturated fatty acids (MUFAs) have one double bond in their carbon chains.
MUFA food sources are typically liquid at room temperature and fairly stable for cooking purposes.
The most common MUFA is oleic acid, which olive oil contains in high amounts.
Monounsaturated fat is linked to several health benefits, including a reduced risk of serious diseases such as heart disease and diabetes (5, 6, 7).
One review of 24 controlled studies found diets high in monounsaturated fat lead to significantly lower blood sugar, triglycerides, weight and blood pressure levels, compared to high carb diets. The high monounsaturated fat diets also increased HDL (good) cholesterol levels (7).
MUFAs may also increase feelings of fullness that lead to reduced calorie intake.
In one study, people felt fuller and took in fewer calories for the next 24 hours after consuming bread alongside oil rich in oleic acid, compared to bread that contained less (8).
Polyunsaturated fatty acids (PUFAs) contain two or more double bonds.
They can be divided into groups depending on the location of the double bonds. These include omega-3s and omega-6s.
These double bonds make PUFAs more flexible and fluid than saturated fats.
On the other hand, they’re also far more prone to damage and rancidity.
Studies have found that long-chain omega-3 fats have benefits for inflammation, heart disease, diabetes, depression, and other health conditions (9, 10, 11, 12).
Although you need some omega-6 fats, they can contribute to chronic inflammation if you consume too much, especially if omega-3 PUFA intake is low (13, 14, 15).
Omega-6 fats are very common in modern-day diets. On the other hand, omega-3 fats are usually consumed in much smaller amounts.
Significantly, researchers report that the evolutionary diet of humans provided a ratio of omega-6 to omega-3 fats between 1-to-1 and 4-to-1.
By contrast, it’s estimated that most people now consume these fats in a 15–17:1 ratio (16, 17).
Saturated fatty acids (SFAs) have no double bonds in their carbon chains, so the carbons are said to be “saturated” with hydrogen.
They’re very stable at high temperatures and far less likely to be damaged during cooking than polyunsaturated fats.
SFA intake can raise LDL (bad) cholesterol levels in some people, although this depends in part on the specific fatty acids consumed. It should also be noted that HDL (good) cholesterol typically goes up as well (18).
Overall, research indicates that SFA consumption has a neutral effect on health and doesn’t appear to cause or contribute to heart disease (19, 20, 21).
In fact, some foods high in saturated fat may benefit metabolic health.
For example, studies suggest that the medium-chain triglycerides in coconut oil and palm oil may boost metabolic rate and reduce calorie intake (22, 23).
The American Heart Association recommends that only 5-6% of your fat intake should be saturated. In other words, if you’re on a diet of 2,000 calories a day, you should consume around 13 grams of saturated fat per day (24).
In a trans fats molecule, hydrogens are positioned across from each other rather than side by side.
Small amounts of trans fats occur naturally in dairy and other animal foods. However, nothing is natural about the trans fats used in processed foods.
These trans fats are produced by adding hydrogen to unsaturated fats to create a product that functions more like a saturated fat. Ingredient labels often list them as “partially hydrogenated” fats.
Consuming trans fats can lead to a number of health problems. Artificial trans fats are linked to inflammation, unhealthy cholesterol changes, impaired artery function, insulin resistance, and excess belly fat (25, 26, 27, 28, 29).
Research has linked the intake of trans fats with a higher risk of cardiovascular disease (30).
Trans fats are often found in margarine and other processed spreads. Food manufacturers sometimes add them to packaged products, such as crackers, to help extend shelf life.
The appropriate amount of fat to eat will depend on your calorie requirements for weight loss or maintenance. It’ll also be based on your eating style and diet.
You can use this calculator to determine your calorie needs to lose weight or maintain your weight, which is known as your daily calorie goal.
Low fat diet
A standard low fat diet contains about 30% — or less — of its calories from fat (31).
Here are a few examples of suggested daily fat ranges for a low fat diet, based on different calorie goals:
Studies show higher fat diets, such as low carb and Mediterranean diets, offer many health benefits and may be a better choice than lower fat diets for some people.
High fat, low carb or Ketogenic diet
A ketogenic diet:
The percentage of calories from fat will depend on how low your carb intake is, but it will generally be around 75% of calories (32, 33, 34).
Here are a few examples of suggested daily fat ranges for a low-carb or ketogenic diet, based on different calorie goals:
Moderate-Fat Mediterranean Diet
The Mediterranean diet includes a wide variety of plant and animal foods such as:
It typically provides 35–40% of calories from fat, including plenty of monounsaturated fat from olive oil.
Here are a few examples of suggested daily fat ranges for a Mediterranean diet, based on different calorie goals:
Regardless of the type of diet you follow, it’s important to get a balance of different types of healthy fats every day.
Fortunately, many delicious foods can provide the fat you need.
While most foods contain a mixture of different fats, some are especially high in certain types.
Below are examples of foods rich in different types of healthy fats.
Monounsaturated fats are found in most plant and animal foods, but some foods are especially rich in them.
All of these foods also contain omega-6 polyunsaturated fats.
Omega-6 fats are present in most plant and animal foods, including those mentioned above.
However, getting adequate omega-3 fats takes a little more work.
Foods rich in omega-3s include:
It’s worth noting that plant foods, such as flax, contain alpha-linolenic acid (ALA). This can convert to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which may have health benefits.
However, the conversion rate of ALA to the omega-3s EPA and DHA is poor (35).
Healthy foods that are high in saturated fat include:
Fats serve a number of important functions, along with making foods taste better and helping you feel satisfied.
Fortunately, a rather large range of fat intake is actually considered healthy.
Eating the right amounts and right types of fat can go a long way toward reducing disease risk and enhancing your overall health.
Last medically reviewed on October 16, 2020