I was wearing a plaid shirt and Doc Martens, and Pearl Jam was playing on my Discman. It was 1993, I was just beginning to study nutrition at university, and my very-low-fat diet looked like this: cereal with skim milk for breakfast, a cinnamon-raisin bagel and banana for lunch, a fat-free muffin for a snack, and a skinless chicken breast with steamed vegetables and pasta with tomato sauce for dinner. "Fat will make you fat," my friend at the gym had told me. So I was rigid. No butter. No oil. Everything I ate was fat-free – cake, candy, Snackwell's cookies. Lucky me!

Along with most of the North Americans wrapped up in the fat-free craze of the 1990s, I hadn't yet learned the truth about fat: that it's essential. That replacing it with sugar contributes to heart disease. That olive oil and (gasp!) Cheddar cheese are part of a healthy diet. We had a lot to learn.

A rich history
Where did this "fat is bad" message come from? In the 1950s, Dr. Ancel Keys, a professor at the University of Minnesota, began a 15-year multicountry study on the relationship between diet and heart disease. His Seven Countries Study found a link between saturated fat, high cholesterol and heart disease. His work indicated that saturated fat should largely be replaced with unsaturated fat. Armed with this revolutionary information, public-health advocates began bombarding consumers with messages about the hazards of fat. Except the message wasn't clear. Health officials thought instructing the public to reduce only saturated fat would be too complicated, so they just advised us to reduce fat – period.

In 1982, Canada's Food Guide included its first-ever moderation message: "Select and prepare foods with limited amounts of fat, sugar and salt." Not saturated fat. Just fat.

The fat-free craze began
Suddenly, manufacturers were under pressure from consumers to produce low-fat foods. The trouble is, fat adds flavour. When fat is removed from food, it needs to be replaced with something that still delivers taste. And in the '80s and '90s, that something was sugar.

Ironically, this kept products' calorie counts the same, since manufacturers added so much sugar that it replaced the calories that were lost when fat was removed. We devoured bagels without cream cheese and ate fat-free cake. The low-fat message created what has since been dubbed "The Snackwell Effect," meaning people mistakenly thought it was healthy to eat large quantities of low-fat foods regardless of calorie content. The error? Calories add up and contribute to weight gain, whether they come from fat or not. Soon after the start of this calorie free-for-all, waistlines started to grow.

The fact is, replacing saturated fat with sugar is terrible for your heart, as it can lower HDL cholesterol (the good kind) and increase triglycerides (fat in the blood). Plus, excess sugar is a key player in causing obesity, and excess weight is linked to heart disease.

Even worse, some manufacturers who understood that only saturated fat was bad (as opposed to all fat), tried to substitute it with seemingly healthy partially hydrogenated vegetable oils, which were low in saturated fat. But we later learned that hydrogenated oils contain the worst of all: trans-fat.

Fat makes a comeback
Going fat-free was a major misstep, because fat is vital to our diets. We need essential fatty acids for brain development, vision, immune system functions and inflammation control.

In the late 1990s, consumers began to accept that fat was not one single nutrient and that some types of fats were better than others. Finally! Newspaper stories espoused the benefits of omega-3 fats from salmon, walnuts and flax. Nuts, once deemed a diet nightmare, became de rigueur for their beneficial mono­unsaturated and polyunsaturated fats.

In 2007, the newly revised Canada's Food Guide recommended consuming two to three tablespoons of unsaturated fat every day. Salad dressing, oil and mayonnaise were happily added to shopping carts again.
 
The future of fat
Just as Keys recommended years ago, it's still advised to replace saturated fat with monounsaturated and polyunsaturated fats, with an emphasis on foods rich in omega-3 fats (see Good Fat, Bad Fat, below). But is all saturated fat bad? Not according to the latest research. Once vilified, coconut oil may actually help raise HDL cholesterol levels, though the studies are too few to tell for sure.

And full-fat milk products, including cheese, may reduce the risk for cardiovascular disease despite their saturated fat content. Milk products contain protein, calcium, potassium and other nutrients that decrease the risk of heart disease, so their effect on heart health may go beyond the impact of their fat content. Interestingly, foods that contain both saturated fat and calcium, such as whole milk and cheese, don't produce the expected increases in LDL cholesterol (the bad kind) and may actually increase HDL cholesterol.

Time to embrace fat
Forget about focusing on the minutiae of different fatty acids and simply choose whole foods. You'll get better fats that way – and you'll naturally eschew artery-clogging trans-fat, found in partially hydrogenated oil and other processed foods. That's the same idea Keys had in the 1950s, but it was lost along the way.

As a result of his Seven Countries research, Keys discovered the virtues of the Mediterranean diet (two of the countries he studied were Greece and Italy), and, in the 1970s, he was the first to introduce the concept to North America. Now the Mediterranean diet – which focuses on vegetables, fruits, whole grains, milk products, legumes, and sources of healthy fats such as fish, nuts and olive oil – is recommended for people who have diabetes or high cholesterol.

The Mediterranean diet mirrors the way I eat now too. I enjoy whole foods – and the fat that comes with them. My taste in clothing has matured (though my Docs remain in my closet), Pearl Jam is now on my MP3 player, and my fat-embracing diet looks like this: cereal, berries, flaxseeds and milk for breakfast; Cheddar cheese and tomato on whole grain bread with vegetables and fruit for lunch; a handful of almonds for a snack; and grilled salmon, quinoa, vegetables and salad with olive oil vinaigrette for dinner.
Of course, the fat that's filling the deep fryer or baked into a cake is still a nutritional no-no, simply because it comes with little value and many extra calories, and it may contain trans-fat. But fats from whole foods should be staples in your heart-smart eating plan.

How much fat should you consume?
Between 20 and 35 percent of your daily calories should come from fat (that's equal to 48 to 75 grams of total fat in a 2,000-calorie diet). Ideally, your fat intake should be divided to contain:
• Up to 10 percent
polyunsaturated fat
• Up to 20 percent
monounsaturated fat
• No more than seven percent saturated fat
• As little trans-fat as possible

Good fat, bad fat
Choose monounsaturated and polyunsaturated fat (especially omega-3s) more often than saturated fat. Avoid trans-fat.

Types of fat and their common sources
•Saturated fat: butter, beef tallow, fatty meat, lard, and coconut and palm oils
•Trans-fat: processed foods containing partially hydrogenated oils
•Monounsaturated fat: canola oil, olive oil, avocado, almonds and peanuts
Polyunsaturated (2 kinds)   
•Omega-3 polyunsaturated: flaxseeds, walnuts, fatty fish, flax oil, chia seeds
and hemp oil
•Omega-6 polyunsaturated: safflower, sunflower, corn, soybean and
cottonseed oils

Learn more about healthy fats, including how it can help you lose belly fat.

This content is vetted by medical experts

                                          

This story was originally titled "Fat Matters" in the October 2013 issue.             Subscribe to Canadian Living today and never miss an issue!