The main reason fat gets a bad rap is that much of the type we eat comes in less-than-healthy packages such as cream-filled biscuits and potato scallops. The fact we’re wired to crave the flavour fat provides makes it even easier to overeat. But back when woolly mammoth was still a menu staple, kilojoules were hard to come by. Humans evolved to seek out the most concentrated supply of them, and fat, with 37 kilojoules per gram (versus 17 per gram in carbs and proteins), was our best food source for survival.
Though we no longer rely on that primitive urge to stay alive, fat still plays a critical role: it delivers key nutrients to your body. “Vitamins such as A, D, E and K are called fat-soluble because they need to bind to fat to be absorbed,” says Taub-Dix.
“If fat isn’t available, the vitamins can’t be absorbed properly.” Top your salad with low-fat dressing and you could miss a lot of the benefits in those leafy greens – which can also leave you craving a snack later on. “Part of losing weight is being satisfied so you aren’t grazing all day on other foods,” says Taub-Dix. “Studies have found that foods with healthy fats, such as avocado and nuts, take the body longer to digest and therefore help keep you fuller, longer.”
The lowdown on low-fat
Approaching fat the way you do the limbo – how low can you go? – won’t send the scales plummeting. The Heart Foundation stresses that a reduction in overall kilojoule intake, rather than simply fat alone, is the key to weight-loss success. Their research shows while women reduced their average fat consumption by around 3g per day, overall energy intake increased by 350kJ. The result? Women added nearly seven kilos to the scales over 12 years. “The ‘low fat’ message was interpreted as an invitation to indulge without keeping kilojoules in mind,” says Taub-Dix.
Cutting all fat from your diet means you’ll also miss out on good fats that can help you lose weight. A study in the journal Diabetes Care found that a diet rich in monounsaturated fats (such as almonds) may prevent the accumulation of abdominal fat.“Fat is all about the source it comes from,” says dietitian Lauren Blaue. By combining fats and carbs in the same meal you’ll keep your blood sugar stable and help to avoid those hunger-inducing spikes and dips.
This isn’t license to gorge on a family-sized pizza, though. Spread your fat-carb combos throughout the day: natural nut butter on wholegrain toast in the morning; olive oil drizzled on your salad at lunch; guacamole with vegies for a snack. Yum.
The one to watch out for
For all the friendly types of fat, there is one you should keep as an enemy: man-made trans fats, which have been shown to raise bad (LDL) cholesterol and lower good (HDL) cholesterol. Unlike other unsaturated fats, which tend to have health benefits, these have been chemically altered through a process called hydrogenation to make the product they are in easier to sell (for example, some packaged biscuits contain hydrogenated or partially hydrogenated fats to make them last longer on supermarket shelves).Unfortunately, you may not even be aware they’re in a product, thanks to tricky labelling laws. According to
Food Standards Australia New Zealand, “It’s not mandatory to declare trans fats on the label, though they must be declared if the manufacturer makes a nutrition claim about cholesterol or saturated, trans, polyunsaturated, monounsaturated, omega-3, omega-6 or omega-9 fatty acids.” Keep an eye out for ingredients lists that include hydrogenated or partially hydrogenated oils.
Finally, always remember to watch your portions, even with good fats. Fat in any form packs more than twice the amount of kilojoules as protein and carbs. “Often, people eat the right foods but too much of them,” says Taub-Dix. Olive oil is the number-one offender among her clients. One cup has close to 8000kJ, and, unless you’re a stickler for measuring, it’s easy to pour on more than the recommended two-teaspoon serving. (See Size Matters, over the page, for healthy serving sizes.) The bottom line: fat’s like Russell Brand: best in small doses.