Diets high in healthy fats are all the rage, but you can have too much of a good thing.

More people are eating fats, especially "good" fats like avocados and eggs, due to the increasing popularity of the ketogenic diet, Kim Kardashian's lifestyle of choice which cuts down on carbs in favour of more protein and, of course, "good" fat.

Studies have even shown there are many health benefits including improved memory and a longer lifespan.

However, speaking with Daily Mail Online, registered dietitian-nutritionist Vanessa Rissetto warns this new trend isn't all that it's cracked up to be, and there are some rules you need to play by to reap the benefits.

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What is the difference between 'good' and 'bad' fats?

Not all fats are created equal.

People are told to avoid trans and saturated fats, which are often found in french fries, cake mixes and margarine, because they raise low-density lipoprotein levels, or 'bad' cholesterol, which increases the risk of heart disease and heart attacks.

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Low-density lipoprotein collects in the walls of the arteries, causing them to harden and narrow, or atherosclerosis.  People with this condition are vulnerable to heart failure, heart attack, stroke and other problems caused by clogged arteries.

Meanwhile monounsaturated fats and polyunsaturated fats, which are found in avocado and salmon, respectively, are dubbed 'good' fats.

This is because they reduce low-density lipoprotein levels and raise high-density lipoproteins, or the "good" cholesterol.

Saturated fats can also raise high-density lipoproteins, but American Heart Association recommends limiting these fats since they also raise "bad" cholesterol.

According to the American Heart Association, this form of cholesterol protects against heart attack and stroke. Experts believe it acts as a "scavenger" by seeking out and carrying "bad" cholesterol away from the arteries and back to the liver where it's broken down.

This is why many believe these types of fat are better for the heart.

Too much 'good' fat is bad for you

However, Rissetto said this doesn't give people a license to overindulge on healthy fats.

"Fat is fat is fat," said Rissetto, explaining that fat, whether good or bad, can be incorporated in a balanced diet. "There's nothing wrong with eating fat, it's all about proportion."

This means eating a lot of fat, regardless of whether it's "good" or "bad" can lead to weight gain and clogged arteries.

"If you're overeating any fat, that is not good," she warned.

She said plans like the ketogenic diet, which is beloved by celebrities like Kim Kardashian and Megan Fox, only works because people are eliminating other foods while on this high-fat diet.

"If all you're eating is fat and you're omitting other food, of course you're going to lose weight," said Rissetto, adding that when people start incorporating other foods int heir diet they tend to gain the weight back quickly.

According to Dr Josh Axe, a clinical nutritionist, a typical ketogenic diets consists of dietary fat being 70 to 80 per cent total calories, with protein making up 10 to 20 per cent and carbohydrate taking up a mere five to 10 per cent.

Just how much 'good' fat should you eat?

Because "good" fats are labeled healthy, many people think that makes it okay for them to consume as many of it as they want.

"If I'm eating three avocados a day then I'm turning that healthy fat into an unhealthy fat," said Rissetto, adding that people should only be eating a quarter to a half an avocado per serving.

To reap the benefits of "good" fats, people should be mindful of their proportions.

Rissetto, who eats one serving of fat in each meal, said the recommended amount of fats per day is five servings, but she said many people unknowingly overindulge in healthy fats.

"When I tell people they should only use one tablespoon of olive oil per serving, they feel like they're being deprived of something," she said.

A serving of cashews and peanuts is equivalent to 15 whole pieces respectively, according to Rissetto. Meanwhile, a serving of pistachios is 52 nuts.

Nutella and peanut butter consist of two tablespoons per serving, but Rissetto said some people eat a whole container in one sitting.

For breakfast, Rissetto said she eats either two soft boiled eggs, which "contains enough fat and protein for a meal," or a slice of high-fiber bread with a tablespoon of PB fit.

During lunch, she generally eats chicken with vegetables with rice or quinoa.

One of her dinner options is Turkey Taco soup, which includes turkey meat, tomato, sour cream and avocado.

Since her rule is to consume one serving of fat per meal, she opted for non-fat sour cream so that she can eat an avocado.

"I make concessions where needed," she said.