Which of the 3 kinds of fat is good for you and which should you avoid?

Not all fats are made equal, and some may even be good for your health.

University of California, San Francisco (UCSF) Division of Endocrinology professor and sugar and obesity expert Dr. Robert Lustig explained at the “Fats and Sugars: Friends or foe?” forum in Makati Shangri-La that fat is so good, it was part of a normal healthy diet at some point.

“[It was explained to us] that dietary fat makes you fat, because fat was the bad guy, that's why we took all the fats out," he said.

"We now know that, in fact, since the brain is mostly fat, we were actually hurting our children by depriving them of the things they need. If you take out fat, it tastes like cardboard. So what happened? We added back sugar.

"Turns out that sugar was really a bad guy," he added.

According to Lustig, sugar is a direct risk factor for the development of metabolic syndrome, an array of symptoms that include high blood sugar, increased blood pressure, and excessive visceral fat or fat inside the torso that doesn't necessarily show outside the body.

These cluster of conditions increases the risk of developing heart disease and diabetes.

Lustig argued that diabetes is the real enemy as people who are thin on the outside, fat on the inside (TOFI) can get the disease while some metabolically healthy obese (MGH) persons don't develop diabetes. 

“It's not about obesity, it never was. It's about diabetes,” Lustig said.

“Everyone says 'you get fat, you get sick.' And it's the fat that made you sick and it was the dietary fat that made you fat. That is the standard mantra. Therefore, eat less fat because that would mean eating less, therefore you would lose weight, therefore you would get better...and it hasn't worked.”

Fat seen around the body and dietary fat are completely different things.

While the former can be negligible unless it's visceral, the latter can actually help improve health, as seen with all but one kind of fat.

1. Monounsaturated Fat

Per Healthy for Good, monounsaturated fat is found in olive oil, canola oil, peanut oil, sunflower oil, and sesame oil. It is also found in avocados and in many nuts and seeds.

Monounsaturated fat, as Healthy For Good notes, can replace saturated and trans fat in a diet and benefit the heart if eaten in moderation.

Aside from reducing bad cholesterol, monounsaturated fats such as olive oil can also contribute vitamin E and “provide nutrients to help develop and maintain your body’s cells.”

But, as Lustig pointed out, olive oil can turn into the bad kind of fat if it is heated at a certain temperature.

“The problem with olive oil is when you cook with it, people heat it too high. It's meant to be drizzled on a salad. If you heat olive oil, what happens is the excess heat causes the double bond in the olive oil to switch, to flip, to go from cis olive oil to trans, and now you got trans fat, which is dangerous,” Lustig said.

He added, “When you heat any unsaturated fatty acid, you can turn it into trans fat.” 

Under monounsaturated fats are omega-3 and omega-6 fatty acids.

Seen in advertisements for fish, omega-3 fatty acids are “heart-healthy, anti-inflammatory, anti-Alzheimers disease” and the “best thing you can put in your body.”

According to the Harvard T.H. Chan School of Public Health, omega-3 are essential fats that the body can only get from food including vegetable oils, walnuts and other type of nuts, flax seeds and oil, leafy vegetables, and proteins such as fish.

Being a type of polyunsaturated fat, omega-3 can lower LDL or bad cholesterol. This decreases the risk of heart disease by reducing the build up in arteries.

However, not all kinds of fish have this fat, least of all farmed, processed, and canned fish.

“Salmon don't make omega-3s. What makes the omega-3s? Algae. The algea makes the omega-3s, the salmon eat omega-3s, and we eat the salmon. But farmed salmon, what do they eat? They eat corn, omega-6s. So if you're gonna eat farmed salmon, you might as well eat steak,” Lustig said.

Omega-6 fatty acids are good for inflammation and killing off infections and while inflammation sounds bad, Lustig said “you need inflammation, otherwise you'd be eaten by the maggots."

“But you don't need so much inflammation,” Lustig cautioned.

2. Saturated Fat

Per Healthy for Good, saturated fat is found in fatty beef, lamb, pork, poultry with skin, beef fat (tallow), lard and cream, butter, cheese and other dairy products made from whole or reduced-fat (2 percent) milk.

Saturated fat is considered the "in-between fat", as eating too much can drive up LDL in the body but is described as Lustig as “cardiovascularly neutral”, meaning it neither causes heart disease nor helps the body prevent it.

The source of saturated fat also has huge implications for its effect on the body.

“There is dairy saturated fat and there's red meat saturated fat. We combine the two into one, and it turns out they have two different signatures in the body. For example, dairy saturated fat seems to protect against diabetes. Red meat saturated fat may or may not increase risk,” Lustig said.

Under saturated fat are medium-chain triglycerides that are metabolized in a different way; instead of going through they lymphatic system, it goes straight to the liver and is processed by different enzymes.

While Lustig is wary of its effects, MCT oil was a health fad as its processing in the liver supposedly led to greater energy expenditure or fat burning.

These fats can be found in macadamia nuts, coconut oil, and palm kernel oil.

3. Trans Fat

Per Healthy for Good, trans fat is found in fried foods like doughnuts, and baked goods including cakes, pie crusts, biscuits, frozen pizza, cookies, crackers, and stick margarines and other spreads. 

The worst fat of all with no redeeming features, trans fat is unsurprisingly the most common fat found in processed food.

“That's the one that the food industry synthetically made, put it into foods specifically so bacterium couldn't eat them, so that's why you have a 10-year-old Twinkie. If bacterium couldn't eat it, guess what, our mitochondria our cells are refurbished bacteria,” Lustig explained. “We can't digest them either.”

The NHS wrote that eating a high amount of trans fat can “lead to high cholesterol levels in the blood, which can cause health conditions such as heart disease, heart attacks and strokes.”

Additionally, Lustig said that carbohydrates are not truly necessary for a complete diet as glucose — the only essential kind of sugar — can be made from fibrous fruits and sources of fat and protein.

“All the other fats you can make from the essential fatty acids, all the other amino acids you can make from essential amino acids. Vitamins and minerals you have to consume. Everything else is not necessary. Carbohydrate is not on that list. There is no essential carbohydrate. You can make glucose from fat or from protein,” he said.

“You do not need sugar to live,” Lustig said, but fat is essential. — AT, GMA News