I know the calorie restriction work has been replicated in the lab with animal models, but of course a human study would face most likely insurmountable ethical challenges.
People who are now 75-80 had much better nutrition than generations before them. Life expectancy in Finland is projected to increase even more in the future.
Calorie restriction starts to make sense only after adulthood. Prenatal, natal and child nutrition and calorie availability is probably the most important thing extending lifespan.
Finland had a famine 1867-1868. After that expected lifetime started to increase. There was a dip in generations born around civil war and then again during the Winter War and WWII. After that life expectancy continued to increase.
Source: Expected lifetime of population by year of birth. https://www.stat.fi/org/tilastokeskus/elinajanodote.html
I think we have to separate the quality of the food (vitamins, fiber, protein, sodium, etc.) from the quantity that was available, and when. You can have the lack of food in certain periods in Finland in the last 75-80 years, e.g. due to WWII. At the same time it's possible to have better food quality in the same period, due to increased globalization, since Finland probably never had so much access to fruits and vegetables in winter as it does in the last 80 years.
So, it depends on what you mean by “youth”. If you include anything below the 20s or so, then the answer is a strong, emphatic no.
https://www.pnas.org/content/106/41/17290
>Population health did not decline and indeed generally improved during the 4 years of the Great Depression, 1930–1933, with mortality decreasing for almost all ages, and life expectancy increasing by several years in males, females, whites, and nonwhites. For most age groups, mortality tended to peak during years of strong economic expansion (such as 1923, 1926, 1929, and 1936–1937). In contrast, the recessions of 1921, 1930–1933, and 1938 coincided with declines in mortality and gains in life expectancy.
Must have been awkward as a child.
https://www.discovermagazine.com/planet-earth/the-worst-mist...
Sounds like it would be a trade-off then, not a clear favorite, depending on what you're optimizing for. Especially when we can afford to focus on maintaining health at an individual level too.
My grandfather is now over 90 years old, and his and my grandmothers diet has mainly been: 1) meats of different kind, sourced of course from grocery shops but also in a significant portion from nature (hunting) 2) fats, definitely of the saturated kind (animal + butter) 3) potatoes.
There were no salads, olive oils or anything deemed healthy by the modern standards on their plates. There were also no hamburgers, chips (or crisps if you're British), no coke (Coke arrived in Finland in the Olympic year 1952 - but it was deemed unhealthy VS orange soda, maybe by the benefit of the local soda company's marketing) and the main sugary treat was licorice candy and the occasional chocolate.
In summary, lower meal frequency would definitely be true, but also a diet with much more "close to source" ingredients.
(Yes, anecdata)