Contribution of processed foods to lower lifespans

Life expectancy in the United States has not gone up in two consecutive years. Robert Lustig uses an apparent decline in 2019 as support for his assault on processed food. The 2020 report showed a major drop in the statistics. Do these numbers support Lustig’s contention? Or is it a smokescreen? 

2020 is not a good year to use to draw conclusions. COVID-19 became the third leading cause of death obscuring other causes. Deaths were up for accidents, homicide, diabetes, chronic liver disease, and cirrhosis. Deaths went down due to cancer, lower respiratory disease, heart disease, and suicide. Some metabolic diseases went up. Others went down. We do not know the full extent of underlying conditions affecting the chance of death due to COVID-19. Without definitive numbers, we could argue either side. My reading: inconclusive.

Coronavirus made no impact on the country in 2019. That might be a better year to study. Preliminary reports showed a decline in life expectancy. The final report showed a slight increase. No major shifts in any of the chronic diseases appear in the data from the year. Increased numbers of suicides and drug overdoses drove lifespan numbers lower. Case and Deaton describe these causes in Deaths of Despair and the Future of Capitalism. The effect on metabolic dysfunction: inconclusive.

The period 2014 to 2018 presents a clearer picture. Deaths due to accidents, drugs, firearms, and suicides were up. Another cause of death was due to alcohol considered a derivative of processed food. Deaths from Alzheimer’s disease were up 5%. Deaths due to stroke and diabetes were up less than 1% each. Heart disease as a cause of death was down 3% and cancer down 12%. Life expectancy remained stable during this period. My reading: deaths due to metabolic dysfunction were down. What could be the cause of this decline? Less processed food and less ultra-processed food? I don’t think so. Less trans fats. No, they didn’t disappear from processed food until after 2018. The most plausible reason for the decrease is better medical care.

Life expectancy in the United States rose in my lifetime from 67 in 1950 to 79 at the end of 2019. Deaths due to heart disease rose from 525,000 in 1950 to a peak of 750,000 in 1985. It now has decreased to about 600,000 per year. The US population grew from 152 million in 1950 to 328 million in 2019. Heart-disease deaths have declined from 345 per 100,000 people in 1950 to 315 in 1985 to 185 in 2019. Again, give credit to advanced medical care. Using heart disease as a marker, medicine is saving us; processed food is not killing us.

Then there is cancer, the second leading cause of death in the US. Deaths due to cancer rose from 210,000 in 1950 to 460,000 in 1985 and to 550,00 in 2019. Cancer claimed 140 lives per 100,000 people in 1950 up to 195 in 1985 down to 170 in 2019. Anti-smoking campaigns may be the single-most contributor to the slowing of cancer. Estimates suggest that diet accounts for 30-35% of cancer deaths. Tobacco accounts for 25-30% of cancer deaths, and infections for 15-20%. Lung, colorectal, pancreatic, and breast cancers lead to the most deaths.

Robert Lustig would counter that lifespan might not be the best measure. What about healthspan? It is a new concept. By one definition healthspan is “the length of time one is at optimal health.” How optimal does that need to be? Does that differ from peak health? Is it adjusted for age? Does our healthspan end with the first major health incident such as a heart attack or lung cancer? The idea intrigues me. I have downloaded several recent review articles on the topic. I will report on healthspan and the implications for processed food in a later post. I need time to digest the concept. 

Not every study looking at chronic disease and diet focuses on ultra-processed foods. One report looked at a greater range of food classes. Risk of heart disease increased with too much salt, cured meat, and sugared sodas. Risk decreased with more nuts, seeds, vegetables, fruits, whole-grains, and polyunsaturated fats. Healthy dietary changes do not need an avoidance of all processed food.

breakfast cereal
Do these whole-grain, ultra-processed breakfast cereals contribute to or help prevent heart disease?

As scientists we must be careful to avoid reliance on a single statistic. Processed food is not the sole variable affecting American lifespan. More well-rounded approaches give us a better perspective on dietary risks.

Have we reached the ultimate lifespan in the US? No. Lifespan in the US is below that of 45 other countries in the world, six years behind Hong Kong and Japan. Is part of that due to metabolic dysfunction? Yes. Is part of that metabolic dysfunction due to diet? Yes. Is it all due to consumption of processed food? I don’t think so. The data do not support it. Eating too much food and the wrong kinds of food can lead to premature death. Not all ultra-processed food is junk food. Not all junk food is ultra-processed. Processed foods can be a part of a healthy diet.

Next week: How specific food processes change ‘real’ food

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