Low Fat Diets Don't Work
A few years back, Michael Pollan, a US food writer and journalism professor, distilled his years of interviewing experts and researching nutrition into his simple rule for health: “Eat food. Not too much. Mostly plants.” We were reminded of this recently when Michael spoke at the Sydney Opera House.
His philosophy is now so well known, you’ll even find it on t-shirts. People like it because it cuts through the ever-changing nutrition landscape. Eat low-fat … low carb … high protein … sugar free … no fructose … the list of the latest one-food-group-wonder-diet goes on. When it comes to weight-loss and heart disease, one philosophy that was so well-ingrained in us during the 70s, 80s and even into the 90s, and one that even some nutritionists find it hard to move on from, is the low-fat diet mantra.
We’ve taken it to heart, because we were told so often, and by such respected health organisations, that low-fat was the answer to everything. Overweight? Don’t eat fat. Diabetic? Don’t eat fat. Worried about your heart? Don’t eat fat.
But as science moves on, we gather more evidence and do more experiments. We ask questions. Get answers. Ask further questions. And we learn. As a result, what we now know is that low-fat eating isn’t the best approach to reducing heart disease risk, and there’s increasing evidence that low-fat diets could be part of the reason for the obesity epidemic.
A recent study showed that a kilojoule is not just a kilojoule. When it comes to maintaining weight – what really matters is where each kilojoule comes from – fat, protein or carbohydrates 238. The study, published in the Journal of the American Medical Association, showed that after people had lost weight, the most effective diet for keeping that weight off and at the same time protecting their heart wasn’t the low-fat, high carb diet, it wasn’t the low-carb Atkins-style diet, it was a diet that was similar to the Mediterranean diet – high in plant foods, nuts and legumes, plenty of fish, using lean meats, and focusing on low glycemic index (GI) carbs. More importantly, it was a diet with saturated fat kept low, but with plenty of healthy fats included.
This study isn’t the first to show that including healthy fats in a weight control program has real benefits. Another study 240 which compared this approach to a low-fat diet for weight loss found that after 18 months, people lost more weight on the healthy-fat, Mediterranean-style diet than the low-fat diet. The study also found that the healthy fats made it more enjoyable and easier to stick to.
Other studies have also shown that low-fat diets aren’t the answer to heart disease 239. Including healthy fats is an important part of keeping cholesterol levels in check. Reducing saturated fats reduces bad LDL cholesterol, but replacing them with healthy mono and polyunsaturated fats stops good HDL cholesterol from falling at the same time 239. So it’s not low-fat you’re after, it’s ditching the unhealthy saturated fats for healthy unsaturated fats, like those found in avocados, nuts, seeds and oily fish and olive oil.
So including a serve of avo a day not only gives you valuable fibre packed with vitamins, minerals and antioxidants, it’s also a great source of healthy monounsaturated and polyunsaturated fats, to help manage your weight and look after your heart. Great news for all us avocado lovers out there!
Author: Lisa Yates, Consultant Dietitian Adv APD
Lisa Yates is an Advanced Accredited Practising Dietitian with 18 years experience in nutrition, communications, clinical practice, as well as marketing strategy development and implementation.