Dietary Choices And Life Expectancy

Thousands of studies have been published on the risks and benefits of individual foods and health outcomes. For example, red meat has been shown to increase risk of colon cancer. Another example is that whole grains have been shown to decrease risk of coronary heart disease. This type of research is extremely useful and can help guide our dietary recommendations. Now and again, a study is published that looks at the bigger picture and gives us an idea of what happens when you get everything going in the right direction with your diet. 

The Study

This investigation was published earlier this year in PLOS Medicine (Reference #1). It is a meta-analysis of nutrition research that uses life table methodology to estimate how dietary changes impact life expectancy. 

Here are some of the more interesting results from this study:

-An optimal diet was found to be one high in whole grains, fish, fruits, vegetables, legumes and nuts and low in processed meats, red meat, sugar sweetened beverages and refined grains. No big surprises here.

-Switching from a typical Western diet to an optimal diet at age 20 would result in a 10.7 year increase in life expectancy for women and a 13 year increase for men.

-Making this switch at age 40 would result in a 10 year increase in life expectancy in women and 11.7 years in men.

-Making this switch at age 60 would result in an 8 year increase in life expectancy in women and an 8.8 year increase in men.

-Making this switch at age 80 would result in a 3.4 year increase in life expectancy in both men and women.

-Following are the foods most associated with improved life expectancy:

1) Legumes

2) Whole grains

3) Nuts

4) Less red meat

5) Less processed meat

Conclusions And Recommendations

This is a very powerful study that shows just how important that dietary choices are to our health. The main mechanism driving the results of this investigation is that a healthy diet reduces risk of the major chronic diseases, such as heart disease, stroke, type 2 diabetes and cancer.

Another thing to note is that these results only focus on diet and likely underestimate the true effects of an overall healthy lifestyle. In other words, if you don’t smoke, exercise regularly and maintain a healthy weight in addition to eating well, you would likely see even further increases in life expectancy.

As far as recommendations, this study illustrates the benefits of a Mediterranean diet. It is pretty simple to follow: For proteins, focus on lean meats like chicken and turkey, seafood, low fat dairy and vegetable sources of protein such as black beans, lentils and hummus. For fats, focus on vegetable oils, nuts, nut butters and avocados. For carbs, focus on fruits, vegetables, whole grains and legumes.

Limit sugar, bread, pasta, white rice, red meat and processed meats. If you are looking for a great book on the many benefits of eating this way, pick up Dr. Willett’s Eat Drink And Be Healthy. He was the Department Chair at Harvard when I got my doctorate and his book is an unbelievable resource.

References

1) Fadnes LT, et al. Estimating impact of food choices on life expectancy: A modeling study. PLOS Medicine 2022; 19:e1003889.