There really ought to be a parallel food supply chain, for scientific/research purposes, where all ingredients are high-purity, in a similar way to how the ingredients going into a semiconductor factory are high-purity. Manufacture high-purity soil from ultrapure ingredients, fill a greenhouse with plants with known genomes, water them with ultrapure water. Raise animals fed with high-purity plants. Reproduce a typical American diet in this way.
This would be very expensive compared to normal food, but quite scientifically valuable. You could randomize a study population to identical diets, using either high-purity or regular ingredients. This would give a definitive answer to whether obesity (and any other health problems) is caused by a contaminant. Then you could replace portions of the inputs with the default supply chain, and figure out where the problems are.
Part of why studying nutrition is hard is that we know things were better in some important way 100 years ago, but we no longer have access to that baseline. But this is fixable.
I agree this seems pretty good to do, but I think it’ll be tough to rule out all possible contaminant theories with this approach:
Some kinds of contaminants will be really tough to handle, eg if the issue is trace amounts of radioactive isotopes that were at much lower levels before atmospheric nuclear testing.
It’s possible that there are contaminant-adjacent effects arising from preparation or growing methods that aren’t related to the purity of the inputs, eg “tomato plants in contact with metal stakes react by expressing obesogenic compounds in their fruits, and 100 years ago everyone used wooden stakes so this didn’t happen”
If 50% of people will develop a propensity for obesity by consuming more than trace amounts of contaminant X, and everyone living life in modern society has some X on their hands and in their kitchen cabinets and so on, the food alone being ultra-pure might not be enough.
Still seems like it’d provide a 5:1 update against contaminant theories if this experiment didn’t affect obesity rates though.
The main problem of nutritional research is that it’s hard to get people to eat controlled diets. I don’t think the key problem is about sourcing ingredients.
I won’t think that’s true. Or rather, it’s only true in the specific case of studies that involve calorie restriction. In practice that’s a large (excessive) fraction of studies, but testing variations of the contamination hypothesis does not require it.
Some of it, but not the main thing. I predict (without having checked) that if you do the analysis (or check an analysis that has already been done), it will have approximately the same amount of contamination from plastics, agricultural additives, etc as the default food supply.
The obvious objection to my comment would be, what if people who are really obese are obese for different reasons than the reason obesity has increased over time? (With the latter being what I assume jimrandomh is trying to figure out.)
I had thought of that counter but dimissed it because, AFAIK the rate of severe obesity has also increased a lot over time. So it seems like severe obesity would have the same cause as the increase over time.
But, we could imagine something like, contaminant → increase in moderate obesity → societal adjustment to make obesity more feasible (e.g. mobility scooters) → increase in severe obesity.
Studying the diets of outlier-obese people is definitely something should be doing (and are doing, a little), but yeah, the outliers are probably going to be obese for reasons other than “the reason obesity has increased over time but moreso”.
There really ought to be a parallel food supply chain, for scientific/research purposes, where all ingredients are high-purity, in a similar way to how the ingredients going into a semiconductor factory are high-purity. Manufacture high-purity soil from ultrapure ingredients, fill a greenhouse with plants with known genomes, water them with ultrapure water. Raise animals fed with high-purity plants. Reproduce a typical American diet in this way.
This would be very expensive compared to normal food, but quite scientifically valuable. You could randomize a study population to identical diets, using either high-purity or regular ingredients. This would give a definitive answer to whether obesity (and any other health problems) is caused by a contaminant. Then you could replace portions of the inputs with the default supply chain, and figure out where the problems are.
Part of why studying nutrition is hard is that we know things were better in some important way 100 years ago, but we no longer have access to that baseline. But this is fixable.
I agree this seems pretty good to do, but I think it’ll be tough to rule out all possible contaminant theories with this approach:
Some kinds of contaminants will be really tough to handle, eg if the issue is trace amounts of radioactive isotopes that were at much lower levels before atmospheric nuclear testing.
It’s possible that there are contaminant-adjacent effects arising from preparation or growing methods that aren’t related to the purity of the inputs, eg “tomato plants in contact with metal stakes react by expressing obesogenic compounds in their fruits, and 100 years ago everyone used wooden stakes so this didn’t happen”
If 50% of people will develop a propensity for obesity by consuming more than trace amounts of contaminant X, and everyone living life in modern society has some X on their hands and in their kitchen cabinets and so on, the food alone being ultra-pure might not be enough.
Still seems like it’d provide a 5:1 update against contaminant theories if this experiment didn’t affect obesity rates though.
Do you mean like this, but with an emphasis on purity?
The main problem of nutritional research is that it’s hard to get people to eat controlled diets. I don’t think the key problem is about sourcing ingredients.
I won’t think that’s true. Or rather, it’s only true in the specific case of studies that involve calorie restriction. In practice that’s a large (excessive) fraction of studies, but testing variations of the contamination hypothesis does not require it.
If it would be only true in the case of calorie restriction, why don’t we have better studies about the effects of salt?
People like to eat together with other people. They go together to restaurants to eat shared meals. They have family dinners.
there is https://shop.nist.gov/ccrz__ProductList?categoryId=a0l3d0000005KqSAAU&cclcl=en_US which fulfils some of this
Some of it, but not the main thing. I predict (without having checked) that if you do the analysis (or check an analysis that has already been done), it will have approximately the same amount of contamination from plastics, agricultural additives, etc as the default food supply.
Wouldn’t it be much cheaper and easier to take a handful of really obese people, sample from the various things they eat, and look for contaminants?
Wait, no.
The obvious objection to my comment would be, what if people who are really obese are obese for different reasons than the reason obesity has increased over time? (With the latter being what I assume jimrandomh is trying to figure out.)
I had thought of that counter but dimissed it because, AFAIK the rate of severe obesity has also increased a lot over time. So it seems like severe obesity would have the same cause as the increase over time.
But, we could imagine something like, contaminant → increase in moderate obesity → societal adjustment to make obesity more feasible (e.g. mobility scooters) → increase in severe obesity.
Studying the diets of outlier-obese people is definitely something should be doing (and are doing, a little), but yeah, the outliers are probably going to be obese for reasons other than “the reason obesity has increased over time but moreso”.