Certain kinds of fat may actually be more harmful to your health than previously thought.

New research from Queensland University of Technology in Australia has demonstrated a link between consumption of saturated fat and the development of osteoarthritis.

In the medical community, saturated fat — typically found in meats and dairy — already has somewhat of a bad reputation, including its status in the federal government’s latest dietary guidelines.

Weight gain, obesity, and high blood pressure (a cluster of symptoms sometimes referred to as metabolic syndrome) are major health factors in the United States.

All of them are associated with diets containing too many saturated fats.

What researchers say now is that saturated fat may negatively affect health in ways beyond the scope of what we already know.

In particular, by affecting the body’s bones and cartilage.

“Saturated fatty acid deposits in the cartilage change its metabolism and weaken the cartilage, making it more prone to damage,” said study author Yin Xiao, a professor at Queensland University’s Institute of Health and Biomedical Innovation, in a press release. “This would, in turn, lead to osteoarthritic pain from the loss of the cushioning effect of cartilage.”

Read more: Are eggs, meat, and dairy bad for high cholesterol? »

Caution with replacement foods

As both the prevalence of obesity and osteoarthritis have increased in the world, it has become clear that there is some correlation between the two diseases.

Particularly in people 65 years of age and older, the pairing of these two conditions can be especially harmful because they both affect movement, increasing risk of cardiovascular illness.

If you think that passing on that next hamburger will do you some good, make sure you aren’t just replacing it with another fatty substitute.

That’s because researchers at the University of British Columbia (UBC) in Canada say that more common alternatives to saturated fats may also have a negative impact on diet and exercise.

Their findings, published this month, show that polyunsaturated fats caused lower energy and less movement in mice.

Polyunsaturated fats, which show up in fish, certain kinds of nuts, several common cooking oils (corn and safflower, for example), tend to be regarded as healthier options to saturated fats, but the research from UBC challenges that idea to some degree.

In an animal model, a diet high in polyunsaturated fats “results in loss of spontaneous activity with negative effects on whole-body metabolism,” the study authors wrote.

Sanjoy Ghosh, PhD, an assistant professor of biology and biochemistry at UBC's Okanagan campus, and a study author, told Healthline that we can think of “spontaneous activity” as the desire to exercise in humans.

“We always hear that exercise is hard and, more often than not, patients cannot sustain an exercise regimen long term,” Ghosh said. “This is the first data that shows that the type of dietary fats might make someone more or less prone to spontaneously move.”

Read more: Details on new dietary guidelines »

What is good to eat?

UBC’s research also highlights the need for a better understanding of not just what we regularly consume in terms of macronutrients (fat, carbohydrates, and protein), but the types of those macronutrients.

Not all fats are created equal.

It has been a popular topic for some time to classify fats into different categories. You may have heard the expressions “good fats” and “bad fats.”

Saturated and trans fats typically have been understood as “bad,” while monounsaturated fats and polyunsaturated fats are generally classified as “good.”

However, the research published this month from UBC complicates that classification somewhat.

You might wonder at this point, “Well, what can I eat without negatively affecting my health?”

Both studies offer some insight into that.

While the studies touch on polyunsaturated and saturated fats, that still leaves monounsaturated fats, which are found in olive oil, avocados, and a variety of nuts — as potentially healthy fats.

“Sustained spontaneous activity with [monounsaturated fats] could also be a hidden cause for established physiological benefits of the ‘Mediterranean diets,’” write the UCB researchers.

Sunder Sekar, a PhD student at Queensland University, said in a press release that coconut oil may also be a healthy alternative because it contains lauric acid.

“Interestingly, when we replaced the meat fat in the diet with lauric acid we found decreased signs of cartilage deterioration and metabolic syndrome so it seems to have a protective effect,” Sekar said.

Both studies come at an interesting time for many Americans as the ketogenic diet — one that encourages a high consumption of fat— and paleo diet, have both helped shift perception of dietary fat.

Read more: Is coconut oil fattening? »