You probably subconsciously downregulate your physical activity when you reduce calories, due to lower energy levels. If you wear a fitness tracker and equate number of steps to high calories you should see a difference even with slight reductions in caloric intake. Even the amount of fidgeting you do during the day can change your base caloric expenditure.

another thing is to measure total calories intake and spending weekly.

Daily metrics can vary wildly without affecting overall result.

Is spend even relevant to measure versus weight on the scale? Assuming you work out consistently?

That was my exact personal diagnostic, until 2018. My weight very slowly drifted upward, but you start adding 0.5kg-1kg per year over a couple of decades, with a few dips here and there on dietary effort, and the result was a health disaster.

My solution, and mine alone after trying oh so many different diets and strategies, went through regular aerobic exercise, at a rate of 3-4 hours per week. In my case it was swimming, because I like it; cycling or running would have had the same effect, I believe.

It worked. I lost almost 30kg over about 2.5 years. Why did it work? I don't really know. I can tell you that basal expenditure certainly has gone up, as I had to get into shape to swim 4-5km a week. Of course, swimming a few km introduces some expenditure of its own. However, I had already tried gym and other sports, which should have the same effects, with far worse weight control outcomes.

So, for me, regular aerobic sessions of longer than 45min did the trick. I don't know why, so I can't promise it will work for anyone else, but you might as well try it for a few months. Don't expect huge, rapid, losses in weight, just a very consistent downward trend.

I can't say I seriously tried anything else, but the same approach worked magic for me. I started running and swimming, slowly ramping up to four hours per week (previously zero active exercise for the past 20 years) and have been consistently losing weight for 20 months now. About 15kg down from the starting point and no signs of stopping (though rate is slowly decreasing).

At current trajectory I'll be at normal weight by summer. Two years ago and for many years before I was balancing on the edge between overweight and obese.

I had periods in my life when I was very seriously athletic. 8 hours per week of serious martial arts, and maybe 6 hours of cycling.

I *still* had to really starve myself to lose fat. My aerobic fitness was excellent, as was my flexibility. My core strength was awesome. Fat was another matter.

I'm not the only one like that.

I know people for whom cutting down eating works, and people for whom exercise works. I'm not one of them.

As a footnote, I couldn't lose 30kg without seriously injuring myself. I'm overweight, but not deeply obese. Losing 15-20kg would put me at an ideal fat level.

Conversely, you could increase your caloric intake and still lose fat if you ate only beef, which is the diet I recommend.

Rabbit would be even faster but you do have to supplement fats to avoid dying.

You have to eat the fattiest cuts of ribeye steak to really make the "lion diet" work. (Yes, I know that Michaela Peterson named this diet and she and her father are morons, but the diet definitely works in spite of them.)

> but I think the conclusions one draws from it fail to take into account how much the body can control expenditure.

Yes, this is has been observed and studied. From this page: https://physiqonomics.com/constrained-energy-model/ the relavent source materials are:

https://pubmed.ncbi.nlm.nih.gov/26832439/ https://pubmed.ncbi.nlm.nih.gov/34453886/ https://pubmed.ncbi.nlm.nih.gov/34519717/

So, yes, it seems that the body "compensates" and controls expendeture as you've suggested.

Speaking in general, there are a lot of details to consider for CICO. When people count calories to below their TDEE, their estimate of TDEE is just that, an estimate, not their actual TDEE.

When calories are counted, how accurate are calories being counted? FDA regulations in the US call for the nutritional information on packaging to be +/- 20%, and when audited, the information is often found to be outside that ranges.

Every gram of glycogen stored in your muscles, the body also stores 4 grams of water. The cycle of exercise, fasting, caloric restriction, and refeeding and glycogen storage are going to cause large swings in weight that can make it hard to pull out trends until several weeks/months have gone by, but frequently people are micro-focused on daily weight flucuations and draw their conclusions about diet and weightloss from what is effectively changes in glycogen storage/water weight.