xep comments on Intermittent fasting no better than typical weight loss diets, study finds

[–] xep@discuss.online -2 points 8 months ago* (3 children)

You can question whether there is metabolic advantage to consumption of certain types of food

Yes, this is a much better question. Our bodies do not seek energy, but the substances that are required for our biological processes.

were warm blooded creatures

Yes, our body temperature is regulated by our biological processes and at the same time the converse is also true. It's much more complex than doing 'work'. That would again be an oversimplification. Thinking of the body as a thermodynamic system like a bomb calorimeter is silly.

What is the error margin when measuring food? To save you the trouble, it's about 20-25%. Unless we compensate by considerably under-consuming the amount of food we eat, the sheer amount of noise alone caused by this error margin makes it meaningless.

permalink

fedilink

source

parent

hideshow 3 child comments

[–] AliasAKA@lemmy.world 5 points 8 months ago (2 children)

Sure but then what is your alternative for easily assessing in a reportable way what the energy density of a food is? Bomb calorimetry doesn’t say “you will get this amount of energy from a food”, it simply says “a gram of this material has about this much energy density.” Evolution has done a remarkable job of maximizing energetic recovery from compounds, and it’s simply true that eating more energy in the form of food than is used by the body will result in the body storing said excess energy. Kcal is a convenient relative metric that does correspond to this phenomena. That is objectively true. Is it exact? No. Does it claim to be exact? Again no, but you can calculate the yield by looking at digestive and metabolic processes within constraints and the relative amount is still useful as a gross measure.

It’s fine to say that kcal aren’t what we eat. But then food isn’t really what we eat either. Food is simply compounds that our body can use to perform chemical work. You can quantify this work. And you can use a word other than work to describe chemical reactions, but the semantic point is conserved regardless.

A good proxy for this general capacity in a human body from organic digestible material is kcal. If you have an alternative to this that is easily calculated and also easily understood, I’d recommend writing it up and submitting it to a nutrition or medical journal, where it can be peer reviewed, and if it holds merit, published, to be more broadly examined, and perhaps adopted.

permalink

fedilink

source

parent

hideshow 2 child comments

[–] xep@discuss.online 0 points 8 months ago* (1 child)

A good proxy for this general capacity in a human body from organic digestible material is kcal.

What I'm getting at is that measuring the 'energy' of food is meaningless. It's a waste of time at best, and when someone is mislead into thinking that they can eat 100 kcal of sugar (if we can even accurately determine that!) instead of nutrients then it can even be harmful.

You can quantify this work

In the human body? How do you propose to do this?

food isn’t really what we eat either

I'm pretty sure we generally eat food. We surely don't eat energy.

If you have an alternative to this

Let's start by not talking about energy at all. It's biology and chemistry.

permalink

fedilink

source

parent

hideshow 1 child comment

[–] AliasAKA@lemmy.world 4 points 8 months ago* (last edited 8 months ago)

The oxidation of sugar, which is accomplished in our bodies, can be directly measured. The end products are CO2 and H2O. If you fully combust sugar in a bomb calorimeter, the energy release is equivalent. So whether your body breaks apart something, or fire breaks apart something, they are calorimetrically equivalent, which is why people even bothered with kcals for food in the first place.

Edit: I should note just to head it off at the pass, aerobic oxidation in the body is about 35% efficient. You can measure this by looking at the metabolites formed, and the remaining 65% of the theoretical energy can directly be measured as heat, so when I say that whether our bodies do it or a calorimeter does it, I mean that the total energy is conserved because the laws of thermodynamics apply. If you eat more sugar your body will oxidize it and yield the same stuff, or possibly store it as fat. If you eat protein you can do the same measures, it’s just a slightly different process to enter the metabolic pathways. Fire is just a chemical process and reaction, after all, it’s not special. Your body also does chemical reactions.

Whether you see value in it or not, kcals observe a physical reality which has value within human cells and can be used to describe how human bodies interact with food in an energetic landscape. It does not purport to solve all of human nutrition, and nobody sane uses it for that. It is used as a gross representation of energetic equivalence, for which it serves its purpose reasonably well.

So again, if you believe your interpretation of human nutrition and biology and chemistry is novel or more useful, then submit to a journal your recommendations. Journals even accept review papers which are simply syntheses of existing papers, you don’t even have to conduct experiments. You can literally just go on pubmed and synthesize a paper and submit it for publication.

Don’t submit to a predatory journal though that uses a pay to publish format. Submit to an established, peer reviewed journal.

Conversely, just publish it on bioarxiv or something and then post it here for people to go to and review, though this is not as good as getting it peer reviewed.