Best diets for longevity

Many studies have looked at cultures and areas where there are a high proportion of centenarians (people over 100) and looked at their eating habits. There have also been longevity and health studies to see if these cultures have a lower occurrence of certain diseases. ALthough no direct causal effect has been found a correlation had been made between diet and longevity. At the core of each of these diets, are some common themes; reduce calories, increase fibre, healthy fats, plant based foods and decrease processed and sugary foods.

“There’s so much debate about what type of diet is better – low carbohydrates or fat, increased protein, intermittent fasting, etc. – and I think time will tell which of these are important, But CALERIE is a very well-controlled study that shows a simple reduction in calories, and no specific diet, has a remarkable effect in terms of biology and shifting the immuno-metabolic state in a direction that’s protective of human health."

Reference: VD Dixit CALERIE study

Detailed below are the pros and cons of some of the most popular diets, depending on your food preferences, lifestyle choices and genetic propensity for specific illness may determine which would work best for you.

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Mediterranean diet

A diet rich in olive oil and healthy fats from nuts and grains, rich in omega3 oils from fish and vegetables.  A low intake of processed food, red meat and sweets. 
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What are the findings?
A range of studies have found the risk of heart disease and stroke is reduced by up to 35%. Also the Mediterranean diet is seen in 'Blue Zones', where many centenarians have been found.
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Risks?
That people eat too many calories and gain weight from over indulging in the healthy fats and misinterpret the diet as pasta and processed meats that they may eat in the Mediterranean on holiday.

DASH diet  - Dietary Approaches to Stop Hypertension

A diet that was devised to reduce blood pressure it advocates, fruit, vegetables, lean protein and low salt intake.

What are the findings?
It was created when it was noted that people who were vegetarian and vegan had far lower overall blood pressure. There have been clinical trials that have backed up the findings that blood pressure is reduced, in addition to a decrease in heart disease, obesity and diabetes.
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Risks?
Outside of clinical trials it has been found hard to maintain, therefore there are no long term studies of it. Reducing salt intake is good but eliminating it totally could be dangerous. 

There is also the MIND diet, which combines the Mediterranean and the DASH diet to combat the onset of alzheimer's, like both diets it encourages varied plant based foods at its centre. It differs on the fruits it suggests which are mainly berries and also focuses on green leafy vegetables and avoiding butter and cheese.  There have been studies on Mind but they are not as extensive as the Mediterranean and the DASH diet. 

Japanese diet

A  diet high in fish, vegetables, grains with small amounts of meat and soy with a minimal intake of dairy and fruit. They drink matcha and green tea known for its antioxidant properties and consume seaweed, fermented and pickled vegetables. They also believe in the philosophy that you should only eat until 80% full. 
‍What are the findings?
Okinawaya, an island in Japan has the highest number of centenarians, which in part is attributed to the Japanese diet.  Overall mortality rates from cardiovascular diseases were lower from those who followed a Japanese diet. 
‍Risks?
Ecologically it will be increasingly hard to eat a diet so dependent on fish.

Plant based diet/ Low protein diet

A diet that is rich in fruit and vegetables, with very low meat intake. It should also include low processed food otherwise the benefits are significantly reduced.
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What are the findings?
Overall mortality rates are not lowered (or not proven) yet, however healthier outcomes are seen with less instances of age related diseases. Brain volume has also been seen to increase with a plant rich diet, which in turn is said to be an indicator of lower dementia risk. The newest study out 2022 has stated that plant based diets can increase life span by 10 years.
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Risks?
They need to be well planned and balanced with nutrient rich food, otherwise they can conversely be worse for you than a conventional diet. 

Fasting and calorie restricted diets  

Limiting your food or calorie intake on certain days or at certain times. Two of the most common fasting regimes are the 5:2, eating normally for 5 days and then have a considerable reduction in calories - some say as low as 500 calories a day for the other 2. The other is the 16:8 diet only eating within 8 hours of the day. 
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What are the findings?
The scientific theory is that by reducing your calories intake for periods of time you put your body into a metabolic state which will help our bodies restore and repair. Studies have shown this being effective only in animals up until 2022, but a new study has been published that looked at calorie restriction in humans over a 2 year period and did find a reduction in inflammation, which is the major cause of disease.
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Risks?
The calories you to do intake must still follow the basic rules; balanced diet with not too much sugar and processed food and consuming vegetables and fruit. 

Key components of a healthy diet

• Eat healthy fats; olive oil, oily fish, nuts and grains. 
• Lower your red meat intake
• Eat a large proportion and variety of fruit and vegetables
• Eat less processed and sugar based foods - high sugar diets can lead to gum disease which in turn can lead to an inflammatory state. 
• Have periods where you reduce calorie intake or the hours in which you eat