For too long, fat has been demonised.

Thankfully, experts are slowly unravelling the blanket ban on lipids.

Rightly so, for the real diet enemies are far more specific — and deadly.

• This is the best diet for losing weight

• Palm oil hides as ‘vegetables’ on food labels

• The sugary treat we all drink is ‘killing’ us

A committee of scientists who advise the US government on dietary guidelines this week asked for the ‘fat ban’ to be removed.

As a result, it is likely Americans will no longer be told to restrict the total amount of fat they eat, reversing a 60-year trend in nutrition.

Instead, US consumers will probably be told to eat healthier, unsaturated fats.

This is a wise move, something Australia has already begun, an expert told The New Daily.

“Fat was made out to be the big evil in the diet,” said lifelong nutrition researcher Professor Neil Mann, who recently retired.

“We were told that if you took fat out, or reduced it significantly, then all our problems would go away and everything would be hunky dory.

“The reality is, that’s not the case.

“As we’ve seen, the actual fat consumption in America has been dropping for 40-odd years but the obesity problem is getting worse.”

What to avoid

The real enemies are palm oil, white flour and refined sugar — the main ingredients in junk foods.

“When you think about junk food, particularly the processed-type foods, it nearly has all these same ingredients,” Professor Mann said.

In an effort to avoid all fats, many consumers replaced it in their diets with starchy, refined grains and sugar, both of which cause diabetes.

“I worry more about people’s carb intake than their fat intake.

“Particularly as people get older and heavier anyway, diabetes becomes the real, main issue.”

What to eat instead

The key is to eat unsaturated fats, whole grains and healthier kinds of sugar.

Acceptable kinds of fats include canola oil, olive oil, lean meat, nuts and soybeans. Dangerous fats are found in visible meat fat (the thick white bits), heavily processed cheese and fried food.

“Polyunsaturated fats are even positively healthy. In fact, you have a detrimental health effect if you don’t eat enough of them,” Professor Mann said.

“The most saturated fatty material you can eat is palm oil, which is dirt cheap. Most of our processed foods are absolutely loaded up with it.”

Sources of whole grains include brown rice, quinoa, rolled oats and multigrain bread.

The paleo diet says all grains are bad, but this is “extreme” and an oversimplification, Professor Mann said.

“Humans didn’t evolve eating lots of starch, but we can tolerate it.

“The trouble is, we refine it into this post-digested state that, as soon as it hits your intestines, it floods into your blood as glucose, as blood sugar, straight away.”

Meanwhile, sugar should be eaten as whole fruit, not juice, and definitely not in the form of sugary treats and soft drinks.

“The brown stuff still has a few minerals and vitamins in it, but the white stuff is purified.”

Vegetables are the ultimate super food, in that they are high in dietary fibre, vitamins and minerals and completely devoid of refined sugar, starch and saturated fat.

For more information on healthy eating, see the national dietary guidelines.