Yes, even with healthy fats, there can be too much of a good thing.

By Julia Malacoff
November 29, 2018
Photo: domoyega / Getty Images

Thanks to the sudden popularity of the ketogenic diet, fat has been thrust into the spotlight. Of the three macronutrients (protein, carbs, and fat), it's fair to say it's the buzziest at the moment. People are even making "fat bombs" and eating bacon on the reg to increase their daily fat intake in the name of health. Others (maybe those who have watched What the Health?) take the opposite approach and advocate for low-fat, zero-oil, plant-based diets.

But how much fat is it actually healthy to eat, and how low-fat is too low? Here's everything you need to know, straight from nutrition pros.

What are the different types of fats?

FYI: Not all fats are created equal. (That's why the term "healthy fats" exists in the first place.) There are four main types of fats:

  • Monounsaturated fats are found in plant foods like nuts, avocado, and olive oil.
  • Polyunsaturated fats are found in nuts, seeds, olive oil, and certain kinds of fish. They also include omega-3 and omega-6 fatty acids.
  • Saturated fats are mostly found in animal products like meat and dairy.
  • Trans fats are mostly man-made and created by a process called hydrogenation that turns liquid fats into solids. This process has been banned in the U.S., since it can raise your LDL ("bad") cholesterol and lower your HDL ("good") cholesterol. Small amounts of trans fats also occur naturally in some animal products, like fatty cuts of meat.

Of these four, dietitians recommend focusing on monounsaturated and polyunsaturated fats, eating saturated fats in moderation, and avoiding trans fats entirely.

"Monounsaturated and polyunsaturated fats improve blood cholesterol levels and reduce the risk for heart disease," explains Kimberly Yawitz, a registered dietitian with McDaniel Nutrition Therapy. "There's also some evidence that they lower the risk for type 2 diabetes, particularly when they replace refined carbohydrates like sweets, white bread, and fruit juices. Omega-3 fatty acids have also been found to lower blood pressure, decrease blood triglycerides, and prevent fatty plaque from building up in the arteries."

Here's how to find the right amount of daily fat intake for you.

With all the high-fat/low-fat aficionados out there, it's hard to know what's actually right for you. Here's what experts suggest for figuring out your own personal ideal level of dietary fat.

Start off with the standard fat recommendation. If you're not sure what fat intake is right for you, give dietitians' standard recommended daily intake a try and take it from there. "A good rule of thumb is to aim for 20 to 35 percent of your calories from fat," says Maryann Walsh, a registered dietitian in Jupiter, FL. "You can multiply this percentage by your daily calorie intake, then divide that number by 9 to get the grams of fat per day." If math isn't your thing, apps like MyFitnessPal can help you figure this out, says Walsh.

Think long-term. Sure, that keto diet might sound like a good idea right now, but can you imagine yourself eating that way a year from now? If not, experts recommend picking a fat intake you can stick with. "Think about the healthy foods you love eating on a daily basis," suggests Yawitz. "If you're a carb queen, you'd probably do well with a low-fat diet. A good starting point would be about 25 percent of your daily calories from fat. If you enjoy nuts, seeds, avocado, and cheese, you'd likely feel deprived on a lower-fat diet. You'll probably want to aim for 30 to 35 percent of calories from fat."

Keep an eye on your numbers. "Once you set a goal for your fat intake, try tracking your meals and snacks for a few days," says Yawitz. "As you track, pay attention to your hunger and energy levels, as well as your body weight. If your body weight increases more than you'd like, you may need to either lower your fat intake or cut calories from carbs or protein. You may also try adjusting your fat level if you're at the lower end and frequently find yourself tired or hungry."

Have some fat with every meal. "The best rule of thumb is to include a plant-based source of unsaturated fat at almost every meal/snack," says Rachel Fine, a registered dietitian nutritionist at To The Point Nutrition. "Not only does adding fat to a meal improve satiety, but it also helps to maintain blood sugar levels by balancing the carbohydrate in the meal. Overall, meals and snacks should be a balance among the three macronutrients: complex carbs, health unsaturated fats, and lean protein."

Do you. "At the end of the day, there are a lot of opinions out there, but you need to do what works best for you," says Walsh.

What's the deal with high-fat diets?

High-fat diets are surging in popularity right now. But are there any real benefits to eating a higher-fat diet? "High-fat diets have gained a lot of popularity because people often experience weight loss in the first week or two. However, it's important to keep in mind that when limiting carbohydrates in the diet, you will initially lose water weight, not experience true fat loss, explains Lauren Manganiello, a registered dietitian and certified personal trainer. (People also experience something called keto flu, partially due to the fact that they're losing more water than normal.)

High-fat, low-carb diets are also not a great idea if you're super into fitness. "In order for athletes to perform optimally, they need an appropriate balance of carbs, protein, and fat for performance as well as recovery," says Manganiello. "Typically, I would not recommend a high-fat diet for an athlete." (FWIW, there are some endurance athletes who swear by a higher-fat diet. Here's what you need to know about exercising on the keto diet.)

On the plus side: "Many people often claim that they don't feel as hungry on high-fat diets compared to other diets," says Manganiello. "This is probably because fat helps contribute to us feeling satiated after a meal." Still, satiety is subjective, so this isn't a guarantee.

What about low-fat diets?

The low-fat approach is one nutrition pros are more open to, as long as you're not going *too* low. "Dietary fat has many important functions in the body," notes Yawitz. "It helps insulate the body against cold and is important for healthy skin and hair. Unsaturated fats have also been found to promote brain health, reduce inflammation, and ward off depression and other mood disorders. For optimal health, you need at least 20 percent of your calories to come from fat."

There are some legit benefits to keeping your fat intake in the lower range (20 percent of your daily calories or slightly above), though. "A low-fat diet approach is an effective method of calorie control, as fat has 9 calories per gram versus carbs and protein, which have 4 calories per gram," explains Walsh. There is also positive research pointing to a plant-based diet as beneficial for preventing cancer and cardiovascular diseases, she says.

"I typically recommend that women with a family history of heart disease or abnormal cardiovascular labs follow a lower-fat diet that includes a variety of plant foods," says Yawitz. "For these women, 20 to 25 percent of calories from fat is a good starting point. It's also important to limit saturated fat to less than 7 percent of daily calories." (Related: Can Saturated Fats Help You Live Longer?)

Remember: When in doubt, listen to your body and practice healthy eating habits that you think you can stick to your whole life, says Walsh. "The best nutrition plan is the one that works for you and incorporates the foods you love."

Comments (1)

December 17, 2018
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