Ask HN: Any weird tips for weight loss?

Not only will you drop a few percent off your daily calories, but we are conditioned as children that we cannot leave the table until we eat everything on the plate, which apparently damages our ability to recognise being full. Leaving a little bit each time does seem to help break down that conditioning over time. You don't need to finish it all.

Other tips to feel full sooner, take longer to eat something and precede meals with a glass of water.

Get a kitchen-scale, it makes tracking serving sizes/portions 20x easier & accurate

You can train yourself to go from 8 hours (sleep) to 16 hours pretty easily.

Once you get to a point where you can one-meal-a-day comfortably, then extending this to a 48hr fast once a week becomes relatively easy too.

When you switch air to 100% oxygen, the primary effect is that the gas you breathe in do not have any of the non-oxygen gases. For carbon dioxide, this is about 0.04%, which your lung increase during exhale to 4-5%. The gain thus is those 0.04%, which isn't significant enough to do anything.

When we breathe in a gas the exhale matches rather closely what we breathed in. If it is air, the exhale will be 78% nitrogen which matches the 78% nitrogen that went in. Out of the 21% oxygen, about 17% will go out, together with those 4% carbon dioxide. the remaining 1% will be mostly argon, neon, and other stuff.

If we take in 100% oxygen, 4% will be metabolized into carbon dioxide and ~96% oxygen will go out during exhale. There will likely also be a small portion of nitrogen, but I don't recall how much if a person is fully decompressed to begin with (ie no diving, no climbing, no air travel, no change in elevation). Metabolizeing of oxygen generally do not increase in any significant amount with increased pressure.

But not only won't it benefit weight loss, pure oxygen is dangerous. The more oxygen is circulating in the blood, the more it will react and creating oxygen radicals. Too much and some very nasty effects occurs to the central nervous system, lungs, and/or eyes. People trained to deal with elevated oxygen exposure need to closely monitor the pressure and the exposure time (hours, total for a day, total for a full week).

Oxygen is however a great tool for other uses. One can use it to decrease nitrogen uptake when people are under increased pressure, and also help decompression of inert gases. During disease and injuries, the increase oxygen in the blood increases the odds that the cells can still take in oxygen, reducing cell death and improving outcomes. Oxygen is also used by the immune system, through there is a lot of unknowns there when it comes to over 21% in 1 ATA. Great stuff during specific circumstances under the right management.