[jonathan920]

I actually lived in Japan for 2+ mths , ate like how I ate more than what I ate in Singapore , literally lost 5kg. I was remote working there but do travel out and walk during weekends.

I actually miss the dirty oil fried food from Singapore , it’s much nicer when it’s greasy. Japan cooking oil is very clean , food quality is much higher too, less processed.

[Aurornis]

> but do travel out and walk during weekends.

Traveling somewhere where you walk more and then losing weight is such a common story that it has become a meme.

People also don’t accurately judge how much they eat. The portion sizes were likely smaller and the food composition was different than what you ate in Singapore, even if you thought you were eating the same. A lot has been written arguing about hidden factors in food, but in actual studies it always comes down to eating fewer calories. Eating less calorie dense foods and smaller portion sizes will do it. Even the GLP-1 studies revealed that the magic of their weight loss is directly proportional to reduction of calories eaten, even if patients eat exactly the same foods (but in smaller quantities or less frequently)

[throwaway2037]

    > Japan cooking oil is very clean

I'm confused by this. Is there any science behind "clean cooking oil"? I hear this phrase used often.

[graeme]

A bunch of stuff can go wrong with oil:

* You can use cheaper types that are nothing but omega 6

* You can heat them too high for their smoke point

* They can oxidize and go rancid

* You can use an enormous amount of it

Likely one of the main reasons a lot of restaurant food may not settle as well as home cooking. But in principle a restaurant could do the reverse of these four points.

[majkinetor]

Yes there is.

You can use rancid oil, seed oil, high and long temperatures on polyunsaturaded oils etc. All very unhealthy. Not sure what Japs use though.

[mitb6]

The two most common oils in Japan are canola and soybean, and that's also historically been the case, not a modern change. They definitely do not believe there's anything wrong with seed oils.

[sfjailbird]

> The two most common oils in Japan are canola and soybean, and that's also historically been the case

Umm, canola oil has only been available since the 70s. Even rapeseed oil has only been used since the 50s (it is toxic and unpalatable without modern industrial processing, as are many seed oils).

[mitb6]

Rapeseed oil has been used for cooking in Japan for hundreds of year. The 1950s saw a shift to non domestic production.

https://www.tokyofoundation.org/research/detail.php?id=241

I shouldn't have used canola to refer to both.

Mustard oil is traditional and still very common cooking oil in South Asia that is even higher in erucic acid than rapeseed. People have used high erucic acid seed as good for a long time.

[adamors]

Seed oils being unhealthy is a recent meme I keep seeing, besides health influencers talking constantly about it, the science just isn’t there.

[majkinetor]

It's not recent at all, it's there for decades.

Polyfats are unstable by definition, so when you cook with them, they go rancid pretty fast. That is all very well known.

Besides, seed oils usually produce imbalance of w-3 vs w-6 fatty acids which is also deemed to lead to pro-inflamation effects.

This is all very well known and not a hype. Here is a review from 20 years ago:

https://www.sciencedirect.com/science/article/abs/pii/S09523...

[throwaway2037]

    > they go rancid pretty fast

How fast is "pretty fast"? I assume that most restaurants change their fryer oil at a max once per week. And after cooking, the (underlying) food is more likely to spoil before the oil on the food going rancid.

[majkinetor]

You should assume the worst. Even if oils are not smelly, they can be spoiled and nobody will give a damn at the restaurant.

Fast like you use it once or twice, it goes rancid.

I witnessed restaurants in the Meditterian that keep oils on the tables for salads, and they are rancid due to hot temperatures.

Cook on coconut oil or palm oil, they are the most stable ones. If you go with plant oils, use olive oil as it seets in between poly and saturated oils.

[comice]

it's definitely increased recently. despite it being at best inconslusive and at worse, false.

https://www.bbc.co.uk/future/article/20250530-are-seed-oils-...

[rsynnott]

Huh, I actually thought this particular piece of woo had mostly died out at this point; haven't heard much about it for a few years.

I'd vaguely assumed that it was bored anti vaxers looking for a new Big Bad, but apparently it was Joe Rogan in 2020. Per Google Trends, it seems to have peaked early 2025, which is _much_ later than I thought. Maybe this is a consequence of dumping twitter; I'm missing out on important Oil Discourse.

[throwaway2037]

Well, if you are going to stay open for long, you had better not use rancid oil! Let's ignore that concern for now, as it generally applies to all food products.

"seed oil" -- What is this nonsense that I keep hearing about on social media? Literally, RFK Jr. (US Secretary of Health) says (amoung other crazy things) that seed oils are "poisoning Americans". Is there any peer-reviewed science behind this "seed oil is bad for you" movement? I have not seen it. Also, Japan uses a wide variety of cooking oil. Probably, olive oil is the least used (only in southern European restaurants). I guess that soybean, canola, peanut, cotton seed, rice bran, and sesame seed oil are the most common oils here -- pretty similar to most of the highly developed world (except rice bran and sesame seed).

Google tells me that soybean, canola, peanut, cotton seed, and sesame seed oil are all considered "seed oils".

"high and long temperatures on polyunsaturaded oils": Japan eats more fried food that people realise, but the portion size is quite small. As I understand, to fry food, you need to have a pool of it that is constantly heated to cooking temperature. That seems to qualify as "high and long temperatures". In fact, wouldn't all fried food suffer from the same? I don't understand the science behind this comment. Can you explain it to me like I'm five? (Other people may be interested to learn more.)

Final small thing: It is best to avoid the term "Japs" in English. It has a historical discriminatory meaning in the United States.

[majkinetor]

Who cares about RFK. Even if person X talks nonsence most of the time you can't use that as anrgument for every single thing he says.

The toxicity depends on temperature and length of time. So yes.

Not all fried food suffer, as saturated fats are stable. Coconut oil or palm oil.

For ELI5 you ask AI.

[SenHeng]

I gain around 5kgs each time I’m in Singapore, even just for a week. Singaporean food is incredibly unhealthy. Slurp down that laksa yo.

[okdood64]

I gained weight during my last 2 weeks in Japan. Was eating 4 meals (although relatively light) a day.

[rtz121]

On my last Japan vacation I actually managed to gain weight

[pezezin]

I moved to Japan 7 years ago and managed to gain 10 kilos. It is nowhere as healthy as people say.