It’s the nutrition zombie that just won’t die.

A whopping 65 percent of people want to reduce the amount of fat in their diets, according to a recent Nielson survey, despite overwhelming research that shows low-fat diets may actually promote weight gain.

So how has this monster of myth lived for so long?

Because people still think fat makes them fat, says Donald K. Layman, Ph.D., professor emeritus of food science and human nutrition at the University of Illinois.

And because the government’s new Dietary Guidelines for Americans still tell them to cut down on fat intake, particularly saturated fat.

Apart from urging people to avoid ultra-processed trans fats (still a good move), the new guidelines recommend limiting saturated fat consumption to account for less than 10 percent of your daily kilojoule intake.

Uncle Sam also says to replace saturated fat with “healthier” unsaturated fats. So, basically, watch your intake of rib eye, full-fat cheese, and whole eggs. That’s because replacing saturated fats with unsaturated fats is associated with reduced risk of cardiovascular disease, they argue.

“These dietary guidelines on reducing fat intake are a hangover from an old philosophy,” Layman says. “Just like the recommendation to cut dietary cholesterol went away, I think that the recommendation to reduce fat intake will go away, too.”

Why Cutting Fat from Your Diet Doesn’t Mean You’ll Lose Fat

Yes, fat contains kilojoules (37.65 kilojoules in one gram, to be exact). If you eat a lot of fat, it may contribute to weight gain. But the same goes for any nutrient.

However, when you cut fat, you’re more likely to overdo it in the kilojoule department—upping your risk of weight gain, obesity, and related conditions like Type 2 diabetes and heart disease.

That’s because fat is the most satiating nutrient out there, taking longer to digest than either carbs or protein, he says. When you eat fat, your blood sugar levels stay stable longer and you prevent excess hunger.

And, in most guys, those extra kilojoules they consume don’t come from protein. They come from empty carbohydrates.

“The less fat people eat, the more carbs they typically eat, and people are already getting more than twice their daily recommended intake [of carbs],” Layman says.

After all, your blood sugar may dip more often when you cut fat from your diet, which can make you crave simple, often refined carbs for a quick-hit of energy, explains Florida-based nutritionist Jaime Mass, R.D.

Even worse, processed foods like low-fat ice cream and chips typically contain more sugar and kilojoules than their full-fat counterparts.

“When you remove fat from a food product, it must be replaced with other ingredients in order to provide a yummy, profitable alternative,” Mass says. “So if you take a food that had fat, remove it, triple the carbs, double the sugar, add extra ingredients to support the consistency and flavour, label it fat-free and consume it for years and years, you’re setting yourself up to be overweight and develop health problems, including abdominal fat, Type 2 diabetes, and cardiovascular issues.”

However, when people see a “low-fat” label, they automatically assume it’s healthier, according to researchers from the Cornell. They found when people eat low-fat packaged snacks, they wind up eating about 50 percent more kilojoules that they do if they had eaten the full-fat version.

In one Scandinavian Journal of Primary Health Care study of more than 1,500 men, those who consumed a diet high in dairy fat were at a lower risk of abdominal obesity, a marker of overall health, compared to those who consumed diets low in dairy fat.

Plus, since excess weight is the biggest factor driving men toward heart disease, adding some saturated fat back into your diet might prove best off for your heart, Layman says.

Reach for the full-fat options. Your waistline, heart, and taste buds will thank you.