Diet, not weight the key to longevity

Will Brodie

4 years ago

What we eat may be more important than the way we look, according to a new study.

It concluded that adherence to the Mediterranean diet (MD) is more important in lowering risk of death than whether a person is overweight or obese.

“Our results indicate that a healthy diet is a good measure (of health risk), independent of your body stature,” said study leader Professor Karl Michaelsson from Uppsala University in Sweden.

Australian dietitian Fiona Willer agrees. She told ABC News that body size and the measurement of body mass index (BMI) were overrated methods of assessing health.

“I think we really need to take our focus off BMI as some kind of ring to rule them all, because it’s really bad at any of those jobs that it tries to do,” says Ms Willer, whose PhD research deals with attitudes to weight and diet.

“It’s really not great at a population level, and it’s really damaging at an individual level when somebody goes to a health provider and they’re judged on the size of their body, rather being asked about what their health behaviours actually are.”

Body mass index is your weight in kilograms divided by your height in metres squared.

The 20-year study of 79,000 people following the Mediterranean diet examined links between BMI and risk of death.

Those in the ‘overweight’ category had the lowest risk of dying.

Those classified as ‘obese’ did not have a significantly higher risk of death compared to those who recorded a ‘normal’ BMI.

However, people in the ‘normal’ weight category who didn’t follow the Mediterranean diet had a higher risk of death than people in any weight category who did follow the diet.

The Mediterranean diet in the study consisted of “a variety of fruit and vegetables, legumes and nuts, unrefined or high-fibre grains, fermented dairy products, fish and olive or rapeseed oil”.

Previous research from the University of Bologna concluded the importance of having most of the population following a healthy diet such as the Mediterranean diet is hugely underestimated and adherence to the diet could help to tackle the obesity ‘epidemic’.

In 2017–18, the Australian Bureau of Statistics’ National Health Survey showed that two thirds (67 per cent) of Australian adults were overweight or obese (12.5 million people), an increase from 63.4 per cent in 2014–15.

The Italian researchers recommended a Mediterranean diet as a food model, but also “the most appropriate regime for disease prevention, a sort of complete lifestyle plan for the pursuit of healthcare sustainability”.

“The Mediterranean diet has been identified as having proved to be the most effective among many others in terms of prevention of obesity-related diseases.”

Prof. Michaelsson said his study’s most important finding was that the Mediterranean diet compensated the negative effect of (high) BMI on longevity of life.

“I assumed that some sort of compensation was likely, but I was a bit surprised to see the degree of compensation.”

His surmised that it is effective because it lowers inflammation and oxidative stress. Oxidative stress is “an imbalance of free radicals and antioxidants in the body, which can lead to cell and tissue damage. It occurs naturally and plays a role in the ageing process”.

Ms Willer agrees with the Italian researchers about the importance of promoting healthy diets to the entire population regardless of their weight.

“We really should, if we’re really interested in public health, be focusing on how to make a diet with the foods in this kind of dietary pattern more accessible for the population.”

Professor Gary Wittert, an endocrinologist at the University of Adelaide, is another who believes we should focus on health, not weight.

“People should not focus on weight; people should focus on health,” he said, “then you don’t engage in these diets where you restrict your nutrients, and where people get depressed because they regain weight, which is almost an inevitability.”

He endorsed a study that showed people who followed the behaviours outlined below had a similarly low risk of dying, regardless of whether they were classed as normal weight, overweight or obese.

How to live longer

regular exercise (more than 12 times a month)

diet rich in vegetables and fruit (at least five serves a day)

moderate alcohol intake

avoiding or quitting smoking

get enough good quality sleep

eat at regular times

eat in daylight hours

reduce stress.

A day on the Mediterranean diet (Source: ABC News)

breakfast: slice sourdough bread with chopped tomatoes, red onion, fresh herbs with crumbled feta and drizzle of olive oil and balsamic vinegar. Slice of melon. Greek coffee (or espresso)

snack: fresh fruit (pear, small bunch grapes, a couple of figs) or small handful of nuts (walnuts, almonds, hazelnuts)

lunch: Mediterranean vegetable bake with small serve of rice

afternoon snack: Greek plain natural yoghurt drizzled with honey and a few crushed walnuts

dinner: baked or grilled snapper (or other fish) with salad of cooked leafy greens drizzled with olive oil and lemon juice. Small glass of wine.

Do you worry more about how you look than how you feel?

If you enjoy our content, don’t keep it to yourself. Share our free eNews with your friends and encourage them to sign up.