There’s a scientific paradox in the world of nutrition about what the optimal diet is. A new theory may resolve the paradox. Oh, and help you live forever too.
The majority consensus is the “post-agricultural revolution diet” is best, which says that a majority of your intake should be vegetables and fruits, and that you should severely limit your animal product intake, especially red meats. Some proponents (like T. Colin Cambell of China Study fame) go as far as claiming that a strictly vegan diet is best.
The other camp argues for the “paleo” or “caveman” diet, which says we need to eat what our paleolithic ancestors ate: lots of foods high in animal fat and animal protein, and avoid industrialized grains altogether (some fermented natural grains are fine). Fermented foods in general are encouraged, honoring the fact that before preservation, refrigeration and pasteurization we evolved a symbiosis with bacterias that are critical for our digestion and processing of nutrients.
Both sides agree that processed foods should be avoided at all costs and that nuts, seeds and spices are great. The main point of difference centers around the amount of meat and dairy, and the amount/type of grains. And when you start looking into the evidence, what’s clear is, there’s no clear right answer. There are great arguments (epidemiological and etiological) on both sides, and there are well-respected scientists on both sides as well.
Evolutionary biologist and UC Irvine Professor, Michael Rose, suggests that both camps are right, it’s just that before age 35 or so we should be eating the plant-based diet, and afterwards the meat-based diet. The reason, he argues, is that this will most parsimoniously ease us into a state where biological aging slows down to a crawl and even stops(!)
The basic arguments are laid out here, but I imagine that like everything the devil is in the details. Before you go justifying a McDiet to yourself just because you are an old fart, remember that most of what we are told is meat (or chicken or fish) these days is really just a composite of the corn, hormones and antibiotics that are pumped into these poor creatures in the name of mass-production.
On a personal note…
As for myself, I’ve been self-experimenting recently to find a diet that agrees well with my digestive tract (since I’m otherwise healthy and have no symptoms of, or major risk factors for, chronic disease to worry about). Interestingly, as a 42 year old, in the last couple of years as I’ve moved to an 80% plant based diet and almost had eliminated meats, I found that I was having digestive issues and food sensitivity issues that I’d never had before. In recent months, I’ve added back more (grass-fed, hormone-free, antibiotic-free) meats, increased my pro-biotic intake (e.g. yogurt and other fermented foods), and the impact has been remarkably positive.
The other thing I did was drastically reduce my sugar intake because I found that it was the one item I was truly sensitive to (based on metabolic blood testing). This agrees with the consensus that we are not evolved for digesting highly-processed substances; i.e. we only ever get sugar in the wild when it’s paired with fiber, acids and hundreds of thousands of phytonutrients, all of which affect the metabolic processing of that sugar.
As a small case in point, if I have refined products sweetened with agave (high in fructose) it goes right through me; if I have too much raw fruit, it does not sit well the next day; if I have some fruit with almond butter, I feel great. Experts agree that in order to get the most benefit out of fruit, it should be paired with some form of fatty-acid, and the almond butter has that, plus protein, both of which act to slow down the digestion of fruit and thus the breakdown into sugars. And we know well by now that sugar spikes are what cause insulin resistance, metabolic syndrome and eventually type 2 diabetes.
My personal takeaway from all this is that medical science still has a lot to learn about “optimal health” and that there is clearly no one right way for everyone. Just because statistics show what’s good on average, doesn’t mean that any particular individual is best off following it (this mistake is known as the ecological fallacy, and most scientists and doctors I’ve talked to have no idea they are continually committing it in their work and thought process). As an individual, I am learning to listen more to my body, what it is telling me it wants, and weighing that evidence against both the science and the way my body reacts. When all three are in agreement, this is what I consider optimal to me. And one thing I know for certain is that it’s not optimal for you.