As the tide began to turn in the early 2000s and the claims for low-fat diets grew more dubious, new dietary culprits were called into question, such as refined carbohydrates and gluten. Meanwhile, more research emerged exploring the benefits of diets rich in healthy fats. These days, Flynn is noted for seemingly having known before others that low-fat diets were not optimal for health. “I constantly hear from people now ‘How did you know low-fat diets were unhealthy?’ ” She laughs this off remarking that she would simply always read the references supporting dietary guidelines and was a critical reviewer of the evidence. “I constantly tell my students to not take dietary guidelines at face value; look into the evidence.”
In 2017, Drs. Kevin Hall and Juen Guo published a meta-analysis of controlled feeding studies that compared diets of equal calorie and protein content with variations in carbohydrate and fat content. By designing the study in this way, the researchers could finally find out whether restricting carbs or limiting calories is more important when it comes to weight loss.
The second reason is arguably more important: Vegies taste better with olive oil, so people are likely to eat more. “My rule of thumb is one tablespoon of extra-virgin olive oil to one cup of veg,” Flynn says, adding that sautéing them or roasting are tasty options, plus these methods maintain much of their nutrient value. “Eating veg like this fills you up and stops you being hungry.” An added bonus, she says, is fibre from the veg also improves bowel regularity.
The study looked at more than 7000 participants who were divided into three groups and were tracked over five years. The first group was asked to follow an unrestricted-calorie Mediterranean diet supplemented with additional extra virgin olive oil; the second group was asked to follow an unrestricted-calorie Mediterranean diet supplemented with additional nuts; and the third group was asked to follow a low-fat diet. More than 90% of the participants were overweight or obese at the time of the study and were between the ages of 55 and 80 years of age.
However, this diet is gaining considerable attention as a potential weight-loss strategy due to the low-carb diet craze, which started in the 1970s with the Atkins diet (a very low-carbohydrate, high-protein diet, which was a commercial success and popularized low-carb diets to a new level). Today, other low-carb diets including the Paleo, South Beach, and Dukan diets are all high in protein but moderate in fat. In contrast, the ketogenic diet is distinctive for its exceptionally high-fat content, typically 70% to 80%, though with only a moderate intake of protein.
Looking for that quick burst of energy? MCTs are an especially beneficial supplement for fueling physical exertion, given their high energy density content, rapid rate of absorption and quick metabolic conversion into cellular energy. Additionally, MCTs can be quickly mobilized in the post-exercise recovery phase to rebuild muscles and prevent the breakdown of protein that can occur when the body is putting a maximum demand on the body’s energy reserves.

While it’s delicate and not necessarily the best oil for cooking, cold-pressed or expeller-pressed oil hasn’t been refined so it holds all of its natural vitamins, essential fatty acids, antioxidants and other nutrients better. While unrefined oil is separated without high heat, hot water, solvents and left unfiltered, on the flip side some oils are heated to a high degree, which reduces their benefits.
The cyclical diet is another one that focuses on more carbs. This is more of a cycle—hence the name. You’ll get five days where you follow the standard diet and then two days where you get more carbs. This sort of diet could be perfect for those who struggle to stick to a plan or just know they wouldn’t be able to last without any potatoes, bread or pasta at all. Think of this like your 5:2 diet, where you get two days off.
Jackie Eberstein agrees: “Measure your success by a loss of inches, rather than the scale.” She advises that you accept that weight loss in middle age will be slower than when you were younger. “Remember that you are in this for the long haul. It is an investment in your health as you get older. Have patience. Your long-term goal is to make a permanent lifestyle change as well as lose the excess fat.”
Therefore, consuming a lot of olive oil (or any other fat) can easily lead to weight gain and obesity, which leads us straight to poor heart health. That’s because weight gain increases insulin resistance in many people and leads to a variety of metabolic changes that promote heart disease, including higher levels of cholesterol and triglycerides, as well as higher levels of markers linked with chronic inflammation, like inflammatory cytokines.
Unsaturated fatty acids, whether monounsaturated or polyunsaturated, can lower your levels of "bad" cholesterol (which decreases your risk of heart disease) if you eat them instead of saturated fatty acids, Hughes says. Saturated fat -- found mostly in animal products and in palm and coconut oils -- is the main dietary cause of high blood cholesterol, according to the American Heart Association.
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