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Comment by JumpCrisscross | Hacker News Reader

> how the difference of a molecule of some protein is any different when it's processed?

Not a nutritionist, but I believe the answer falls into two broad categories.

One, chemical: processed foods frequently contain additives, e.g. preservatives, that less-processed food doesn't.

Two, physical: a peach smoothie is digested and hits your bloodstream differently from a whole peach. They're chemically identical but physically different, and that changes everything from how quickly you ingest it, how much of it you ingest, how it hits the stomach and how it hits your gut.

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But why does that matter? Assuming the caloric intake is the same, how does eating a peach smoothie differ from eating a peach? They are the same and get liquified the same. I mean technically when you eat you're supposed to have it mashed up enough that your stomach has to do little as little work as possible (so equivalent to a smoothie as possible). I still don't see how that makes a difference.

Back to the additives, what difference does it make if your body properly disposes of it because it can't break it down and it doesn't get absorbed by you? Or...does it get absorbed by you (which is what I'm partially asking)?

> Assuming the caloric intake is the same, how does eating a peach smoothie differ from eating a peach?

Increasing the number of masticatory cycles is associated with reduced appetite and altered postprandial plasma concentrations of gut hormones, insulin and glucose [0]

[0]https://www.cambridge.org/core/services/aop-cambridge-core/c...

TL;DR It's not just about calories, it's about what the food makes you do later.

If you made a peach smoothie out of nothing but pure peaches, it would be identical to eating the peaches, I'm sure.

I am also not a nutritionist, but from my reading processed foods are bad because (1) they just have far fewer nutrients, vitamins and minerals that our body needs to function, (2) the additives and chemicals that are added sometimes harm our body directly and/or require the body to dedicate resources towards removing, or (3) they harm our microbiome by feeding bad bacteria which similarly produce stuff that isn't good for your body and damaging the good bacteria which we need.

Chemistry occurs at the surface of the food - if you have lumps of peaches in your stomach then they have to be digested, ie broken down. If you drink a smoothie then the surface area available to chemical reactions is a lot larger, so digestion happens quicker. Quicker digestion of sugars causes a larger insulin spike, which is bad. Also commercial smoothies usually have a lot more sugar and fat in them than you'd think, I know you said just blended peaches, but in reality everyone adds stuff to it.

> If you made a peach smoothie out of nothing but pure peaches, it would be identical to eating the peaches, I'm sure.

Faster absorption means higher peak serum glucose levels and higher amounts of insulin released. More insulin translates into more promotion of insulin resistance. IIRC, high serum glucose is also not good for your arterial lining.

> how does eating a peach smoothie differ from eating a peach?

I think that eating a peach smoothie, one where you just take a peach and some ice - throw them in a blender and mix away, is no different from eating a peach[1] but ordering a peach smoothie at Jugo Juice is not peach in a glass, it's some peach and added juice (containing added sugar) and added sugar also some ice, probably with added sugar - all mixed together with some "healthy protein base" which is probably a bit of whey with added sugar - basically a smoothie ends up having very little relationship to the fruit.

Additionally if you slurrify raspberries you can drink them by the dozen in a single gulp - while eating them by hand you'll strike a more leisurely pace and stop once you're feeling full - often times with smoothies and the like we'll over consume because it takes a while for our body to actually realize we're full.

1. Maybe a slight loss of healthy stuff due to fibers separating out and not ending up in the juice but ideally that's negligible.

Often some additives may get absorbed by your gut.

A smoothie vs a peach may well have different glycemic indices. Few people chew their few up to the extent that a bender will break it down. Also, how many peaches go into a smoothie, and how much extra sugar via, say, yogurt, or smoothie mix?

We're not talking about a peach smoothie at jamba juice, we're talking about blending peaches vs eating it raw and chewing it with your teeth. The molecular makeup of the food is 100% the same, the difference is it's physical attributes of it as you ingest it.

and eating a peach means you consume the juice and non juice components of one peach.

if you juiced one peach you get the calories of one peach minus the non juice components. which I'd estimate to be approx 100mls

if you drink a peach smoothie you consume the juices of many peaches minus the non juice components.

> Assuming the caloric intake is the same, how does eating a peach smoothie differ from eating a peach?

Your body has regular teeth. Most people don't chew even 30 times per bite.

A blender has mega-ultra-turbo teeth that are both way, way sharper than a person's and also they never get tired because they're powered by electricity not muscles.

How much chewing do you think is equivalent to blending? My very unscientific guess is that blending is something like 1000 chews per bite or more given that our teeth aren't as sharp as blender blades.

Eventually quantitative differences (number of chews) become qualitative (sugars and starches encapsulated in small bits vs chemically liberated). Blenders do a lot of the work of digestion mechanically well before your body has a chance to do it chemically.

Of all the things that are different about processed foods that have been mentioned in this thread, this is probably the least important, but yes, there is still a difference... they don't "get liquified the same", because when you eat a whole peach you chew it, and when you chew it your mouth is mixing the pulp with digestive enzymes (in your saliva) and also priming the digestive juices in your stomach to adjust for the pH of the incoming matter! This turns out to be important enough that many nutritionists for over a century have emphasized the importance of eating slowly and chewing thoroughly. You can't really do that with a smoothie.

Extracting energy and nutrients from food is highly optimized by evolution for obvious reasons, even in the case of omnivores such as ourselves. Modern "ultraprocessed" food is not adaptive.

Processing can also mean separating out parts of foods to exclude them from the product. Take fiber for example. Processing an ingredient to reduce or remove its fiber doesn't change the molecular make up of the remaining portion of the ingredient. The molecules in = molecules out (minus the fiber).

However, fiber lowers cholesterol levels by preventing cholesterol from being absorbed, and slows the absorption of glucose. When we examine the modulating effects of ingredients and couple that to biological non-linearities, it's not too hard to see how processing can affect how food interacts with the body. Reduced fiber foods, can affect the body in ways different from non-processed food even if the molecules being ingested are identical to those in the original ingredients.

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