Atkins, keto, palaeo, gluten-free, low-carb, low-fat, high-fat, raw, vegan, vego, pescatarian – phew, that’s a lot of different diets!

And it’s by no means an exhaustive list.

The old adage ‘you are what you eat’ has come to be a mantra for good diet and health. It was originally coined by 19th-century German philosopher Ludwig Feuerbach, himself drawing on commentary by an earlier French gourmand Anthelme Brillat-Savarin.

Increasingly, science is finding new connections between diet and our overall picture of health. You may have heard how our gut microbiome acts as a second brain, or that avoiding unprocessed foods can lead to all-cause mortality.

Ludwig Andreas Feuerbach. Credit: Public Domain

But when it comes to many fad diets that promise quick weight loss or improved health, the science can sometimes be skimp. This can change over time as researchers test the influence of diet on general health, weight management and as a medical treatment.

The Mediterranean diet is probably closest to the mark as a lifestyle of choice, in terms of overall health, nutrition, and diet science. It emphasises fruit and vegetable consumption, with some wholegrain breads and cereals, legumes, nuts, seeds and fish, with olive oil as a primary fat source.

This diet is either explicitly endorsed by many health authorities around the world such as the American Heart Association, the Royal Australian College of General Practitioners as a diet for lowering cardiovascular disease risk, or used as a basis for other recommendations. The World Health Organization also advises on ways for the Mediterranean and similar New Nordic diets to be implemented as health policy.

But diet might be better considered about more than what goes in one’s mouth.

Dr Evangeline Mantzioris, Program Director of the Nutrition and Food Sciences Degree at the University of South Australia, says a truer interpretation of the world extends beyond merely food and drink.

“The word diet actually derives from the Greek word diaita, which means the way you choose to live your life,” Mantzioris told the Debunks podcast.

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“So it’s not just about the food, it’s about the exercise, it’s about the social interaction, it’s about the rest. It’s about the sleep. It’s all of that.”

The WHO’s 2019 Health Evidence Network Synthesis Report also acknowledges both social and sleep components of the lifestyle, noting shared eating practices, post-meal siestas and lengthy meal times all contribute to positive health effects.

In terms of the nutritional component, Mantzioris notes that adherence to the diet requires not just an uptake of olive oil, but cutting down on less beneficial foods and an active lifestyle.

Tomatoes, parsnip, radishes, brussel sprouts, squash, carrots, beetroot, and leaves
Credit: Sharon Pittaway, Unsplash

“It’s not just the olive oil, it’s dropping down the meat, it’s mainly a plant food diet, it’s purposeful exercise,” she says.

“I’m always a little bit nervous when people just talk about the diet and the food without considering the rest of it.

“In the 60s, when the health benefits of the Mediterranean diet were seen […] they were out there harvesting, growing their food, preparing their food, doing all that sort of purposeful exercise in the outdoor environment, often in quite steep terrain. So that is just as important.

“The Mediterranean diet continues to be shown to be quite healthy and beneficial in terms of improving chronic disease risk, even without weight loss.”

Mantzioris says that the diet has also been shown to improve cognitive and mental health outcomes.

Diet is the focus of the latest episode of Debunks from Cosmos and 9Podcasts, where we dive not simply into what makes a good diet, but the principles that dieticians and nutritionists look for when recommending one for a patient to consider.