Rates of overweight, obesity and associated conditions like type 2 diabetes are increasing around the world. There are literally hundreds of potential reasons why we are gaining weight as a species, but the quality and amount of foods and drinks that we consume habitually tend to be scrutinised the most, perhaps because we think we understand them the most, or possibly more importantly we think we have some control over them.

In recent years, it is becoming increasingly clear that focusing on single nutrients, ingredients, foods or even food groups is not a recipe for long-term health and well-being, because overall dietary patterns are more important in the long run. For example, there is strong evidence that both the traditional Mediterranean diet and certain traditional Asian cuisines like traditional Japanese diets are associated with longevity and a lower risk of developing chronic diseases like type 2 diabetes, despite being composed of very different ingredients and foods, with very different macronutrient profiles – Mediterranean diets are relatively high in fat whereas most Asian diets are very high in carbohydrate and low in fat. Principles from these tried-and-true dietary patterns like eating minimally refined vegetables, fruits, grains, nuts, seeds, legumes, lean meats/fish, yoghurt and other fermented dairy products, and oils (olive/peanut) can be adapted to suit most people’s personal, familial and cultural backgrounds.

Despite this, most purveyors of popular diets continue to focus on single nutrients or ingredients (e.g., fats/oils or carbohydrates (starches and sugars)) as the cause of all our current lifestyle-related ailments, and most state of course that all you need to do to solve the problem is to avoid them. If only it was that simple …

We have a really good example of the lack of success of the one-nutrient-at-a-time approach – the vast variety of low fat diets contrived in the latter half of the 20th century. Low fat diets (in contrast to traditional low-fat eating patterns as enjoyed by certain ethnic groups for hundreds of years) have not delivered the improvements in health that were expected by their original proponents.

Present day narrative suggests that in an academic showdown spanning several decades and both sides of the Atlantic, “anti-fat” scientist Dr Ancel keys defeated “anti-sugar” scientist Dr John Yudkin, and the low fat message got enshrined in Dietary Guidelines around the globe, paving the way for low-fat variants of all of our favourite foods for the next quarter of a century. In the mean-time we all gained more weight and developed type 2 diabetes. Again, if only it was that simple …

Despite the current narrative, not everyone agreed with Dr Keys hypotheses, and as characteristic of scientific research, academic debate continued. Mindful of this, the very first edition of the Dietary Guidelines for Americans published in 1980 included a range of practical advice to help people choose a healthful pattern of eating. There was a Chapter on how to “Avoid too much fat, saturated fat, and cholesterol” and also one on how to “Avoid too much sugar”, addressing both Keys and Yudkin’s concerns. Dietary Guidelines from 1980 onwards have always included practical advice on reducing saturated fat and added sugars. The problem is, the average person would not likely have known about the Dietary Guidelines as they were a government publication in a pre-internet world. Needless to say, they would not have been on the best seller list in the local bookstore …

However, low-fat diet books were. One of the best sellers at this time in the USA was Nathan Pritikin’s The Pritikin Promise: 28 days to a longer healthier life, and in Australia Ross Horne’s The New Health Revolution. Notably, these very popular authors were not scientists, but well-meaning laypeople who personally experienced dramatic health improvements when they started consuming a low-fat diet. Sound familiar?

Devout followers of these and similar authors sought low fat foods in their local supermarkets and food industry quickly caught on, producing low-fat versions of all of our favourite foods, often replacing the fat with dietary fibres (e.g., gums), maltodextrins, starches, added sugars and refined proteins. The rest, as they say, is history …

Sadly, history has a bad habit of repeating itself. Carbohydrates (in particular sugars) have replaced fats as the nutritional bad-guy in recent years, and low-carb (starches and sugars) books are selling exceptionally well. The current rationale is that high carbohydrate foods stimulate insulin more, leading to fat gain – unfortunately it’s not quite as simple as that – fats and protein also have an effect on insulin levels. But never let the facts get in the way of a good story … low carb foods brimming with refined fats and proteins are filling our supermarket shelves, covered with low-carb/sugar, high protein/fat claims providing them with that all important health halo. The diet industry is once again rubbing its hands with glee … when it comes to sales, any fad is a good fad after all …

It’s time we stopped the nutrient blame game – it will only make matters worse. Diets don’t work in the long run. Enjoy a healthful pattern of eating that suits your cultural, familial and personal food preferences. One size does not fit all.