I think you hugely overestimate the amount of energy used for brooming. It's not like it's a crossfit workout. I don't eat more on the days I clean. My diet with and without a broom will stay the same so brooming is basically free when it comes to energy. People don't use vacuums because they save money on food this way. They use them for their convenience. Vacuums let you save time, not energy. So yes, if you spend the time you save planting trees it's great but we're getting pretty far away from the broom vs. vacuum discussion and we're starting to talk about imaginary people and their imaginary lives.
I think we did not really estimate here, there is just intuition. I made these estimates before for electric bikes vs human powered, and found that, somewhat counterintuitively, electric bikes may quickly become less carbon-consuming.
I do not accept the idea that brooming comes for free. If you add 15 min moderate activity of brooming per day, you may spend, say, 100kcal. If you add it to your daily routine, you need to compensate with food or loose weight. Energy balance in humans is tricky, which is one of the reasons people find it hard to control their weight. But things like replacing a 15min couch sitting with brooming make a difference for weight. Because they consume energy.
Or do you continue to propose that replacing the couch sitting with brooming has zero energy and diet difference activity, is "basically free"? To be clear.
Vacuums help to save time. Carbon impact of vacuums and replacing human-powered activities with solar-electricity-powered ones is not especially studied. Which is why I think intuitive understanding here is lacking. Someone should develop it, maybe write a blog post or a paper.
This is not imaginary, growing replacement of human work at scale has a real impact on carbon consumption. My point is that in some cases, e.g. with electric bikes or vacuum cleaners, human power, even plant-supported, can be more vastful.
Sure, it's also just my intuition but trying to lose weight myself and watching friends try to lose weight and 15 minutes of light activity per day does nothing to your energy balance. To actually use weight I have to cycle hours spending like 2000kcal couple times a week. The 100kcal is 5% of your average daily intake. If you're very active it will even less. Depending on your diet you can excrete more calories then that. Your body will just compensate by adjusting metabolism and you will not have to eat more not to lose weight. With electric bike it's definitely possible to get in the range when you will have to adjust your diet but I don't think it's the case with brooming. Average person will be able to swipe couple days a week without actually eating more, that's why I think it's 'free'. But maybe we have to do some experiments. Do you have a broom?
My weight goes up and down by some 10% every couple of years, I cycle and run (ultramaraphons) and climb and more, and I track and analyse both food and spending with common tools and myself. Which is why I am acutely aware of how at least my body behaves in this respect. And I see people around me who do similar things.
Your point seems to be based on the idea that if it is 5%, it is the same as zero, because metabolism compensates (?). I do not know if this is the case at all or if this is relevant enough to change this 5% number. If this is the case, it is a factor, but it is something peculiar.
Instead, I find, that while a single 10hr trail run spends days worth energy of usual activities, several 5% factors each day, which grow from habits like brooming or taking a walk instead of taking a bus, quickly exceed, or at least strongly contribute to, extreme individual spendings. Also while a long event seems to cause immediate weight loss, it is almost entirely water. So it is a bit hard for me to believe these small spendings are zero. In fact, I find that people often underestimate how simple habits change weekly calorie spending. At least for me, these things make much of a difference in the weight change.
And yes, I have some brooms, and I broom for some 15min a day probably, plus maybe 1h per week.
So now you're taking about 'several 5% factors each day' which is completely different than 5% per day. Of course that if you keep adding those 5% activities up and get to 20-30% more calories burned daily you will start noticing it. But single 5% activity? I highly doubt it. Metabolic adjustments is a real thing: https://pubmed.ncbi.nlm.nih.gov/15044180/ You can excrete as much as 20% of the calories you consume. Burning 5% calories more can just mean you will shit less often or you will sleep better and use less calories during the night. I really think that the idea that 15 minutes of swiping daily will cause to eat more or lose weight is just silly.
I am talking about the fact that 5% add up, both over a single day and over multiple days, which cannot be neglected since it makes a significant impact over enough time.
You seem to be saying that there is a threshold of spending below which the spending is equal to zero and does not accumulate, right? That would mean that MR adjustment is exactly compensating small increases in energy spending.
Thanks for the link! I read the paper to the best of my ability, I am not a biological kind of scientist, but I do not find an indication in it for this kind of adjustment you are talking about. The main conclusion seems to be that MR adjusts after major weight loss. Even after this adjustment, I would deduce, adding 5% would help to limit weight loss.
Do you have a reference which would support your idea that there is a threshold (I guess you are saying it is somewhere between 5% and 20%?) below which energy spending is exactly compensated by MR and hence does not accumulate?
Seriously, maybe it exists, I just never heard of it.
My statement is based on energy conservation, which is also a clear assumption in the article. The net effect on the intake-spending balance can be modified by MR adjustment, but it just does not seem to work the way you propose it does.
So all I'm saying it's not just energy conservation. Human body is not a machine where input=output. Some of the food you eat is excreted unprocessed and your metabolism can just slow down. So if you're just using 5% more energy per day your body can speed up digestion a bit and get more colaries out of the same food or it can slow down more during the night and you will get a better sleep. There's a limit to it of course but your body will deal with 5% change without using it's energy stores.
I hear you, but scientists specifically study how metabolism adapts, for example the study you quote. And, as far as I see so far, they find that the adaptation just does not work like you think it does. You may choose to insist on your intuition despite empirical evidence against it. But I hope you realise this can lead to your expectations, based on this intuition, clashing with reality.
How does it work then? As I understand it depriving body of calories causes it to be more efficient with the calories it gets. What I'm missing? Maybe what you are still missing is that this effect will change depending on amount of calories we're talking about? I doubt there are studies measuring the effect of 100 calories deficit because it would be negligible. Of course if we get into real diet/moderate exercise the effects will change. Is this why you think the effect is different overall?
Sorry for the long silence.
The adaptation works in reaction to large persistent changes, not small 100 restriction as you are proposing.
This also makes sense intuitively, large changes cause reaction while "slow and steady" achieves long term goals.
There are, apparently, discussions referencing just the 100 reduction effect:
Maybe you're right, maybe the metabolism changes will not kick in with 100 calories reduction.
Stil, even if all this is true (I mean, no need to get into the paywalled details) we're taking 4kg over 3 years which in many cases will be totally insignificant. Many people will not start eating more because they lost 4kg. But even if they will then, as this article says, eating 100 calories more doesn't require actually eating 'more' food, just a different one. Get a potato instead of a salad, get different type of bread, or a normal butter instead of 'diet' one. Figuring out if those changes are carbon negative or positive would be incredible difficult as they would depend on the specific products you're changing, where do you buy it and so on but my bet is they will be close to 0. I still think it would take way more than that to offset the carbon footprint of a Rumba.